73 Magazine February 1974 (#161)

most of them are pretty well standardize d also , I und erstand. Fo r normal repeater workon these points. The lin e I use is in northern you won't need that many anyway .New England. Talk BackPower Supply You can modulate th e lin e very easily, to This ca n get a little t rick y . First o f a ll it is listen to a receiver o n the air, o r whateverperfectly po ssible to use the telephone line use you may wish. Figure 7 sho ws th e ea syas the po wer su pply because y o u can find a way to do it by simply includ ing anice 4 2V waiting for you acro ss the red and Lafayette , or similar, AR-1 76 transformer ingreen wires. However, as soon as th e con- series with the line. This has ab out 62n acnection is made to the desired number and impedance o n the line side and 8S1 on th eeit her the line is term inated by the 220n modulation side. This 8S1 is because myresist or , or the handset is picked up , the favorit e small af amplifier at th e moment ispolarity reverses with a bang. This is called the Amperex TAA-300 , which has an 8n\"tipping\" by telep hone co mpanies. This in transformerless outpu t impedan ce.it self is not to o bad as the diode quad switchauto matically gives yo u plu s o n o ne o f it' s The bypass across the termination resistorde o utpu t wires, and a 4K resistor brings this avoids audio lo ss when modulating . You candown to l OY, and the zener diode hold s it use a medium power transistor for th e loadthere. However, there is o ne little fly in the resistor and modulate it , but your powerointment, if the telephone company checks supplies get more involved then . As sho wn inthis line and finds a resistance o f so me thing Fig. 7 you can take the voltage for the aflik e 5 to 10 thousand n across yo ur lin e and amplifier right o ff of the termination resist ora merry little 10 mils draining o ut o n a because o f the isolation provid ed b y theste ady state basis? I have been told that they modulation transformer.may have a slight aversion to this state o faffa irs , so don 't say I didn't warn you . It just Overall System Usemeans you might have to furnish your o wnlOY . At a te nt h of a watt a 100 amp ere hour The main body o f t he amplifier is o necharged battery would last 10 ,000 h ours ,unl ess my arith metic fails me (which is quite thing, which is a good tuned job for tele-easy) . So that's abou t 400 days. phone work . The input and o utpu t circuits are sho wn as a particular example o f o ne Also , mo st rep eaters have an ac linearou nd any way. If you have to run one up particular system that can be made up usingto a mountain , be prepared fo r a lot o f hardwo rk. I did this for 1/ 2 mile u p th e last 1000 this ampli fier. Fro m there on you can figurefeet of elevatio n of a 3 000 fo oter in 19 50, o ut (if yo u're lucky) what system yo u mayand I know. need fo r your particular use.Bandwidth For insta nce, y ou can use a power transis- On this parame ter depends the number oftone code channels y ou can build into a tor to key o n a single relay or a ste ppingproposed system. Here are th e figures Ifound fo r the finished unit exactly as shown relay. This transistor will not latch-up likein Fig. 7 : 10 dB d own at 280 Hz (140 each the scr and is thus easier to use in certainside o f ce n ter) , and 25 dB down at 600 Hz.Granted , y ou are hemmed in o n the low cases. On the other hand it must be keyedfrequency side by the increasing size of the on all the time , whil e the scr does nottuned circuits, and on the high frequency require this. Also the scr can be keyed andside by the inherent cu t-o ff of a normal you can talk o ve r the circuit. As mentioned ,telephone vo ice circuit. However, y ou cou ldget ten cha n nels in between 50 0 and 4000 this article is essentially about a low costHz, with luck . Some lads go lower than 50 0 I - 4000 Hz tuned amplifier. .. .K I e L L Critical Supply Items Cup Cores . Arnold Engineering Co., Marengo , IL or Stackpo le Carbo n Co. , St. Marys St. , St. Marys, PA . SCR. G .E. No . 2N877 , Gerber Electronics, 85 2 Providence Highway, Dedham, MA. Quad Recti fier Stack. No . 18DB4 A-e. Int er- national Rectifier Co., 233 Kansa s s r., El Segundo , CA. AR -176 , AF tra nsfo rmer. La fa yette Radio.

Ralph J. Rom;g WA0KHV Box 16 3 Assaria KS 67416 -\"\ r ' \' '-,\.r \"\ - - / \ \'\.. ,I \ ,T he new Heathkit GC-l 00 5 digital read- Emitting Diodes on a small pie ce of per- o ut clock makes a nice addition to the forated fib erglass board and wiring themmodern harnshack , since y ou can use it to into the low vo ltage B+ circuit , via a pair ofindicate 24 hour time , lo cal or GMT , and limiting resistors. This assembly was thencan sy nchro nize it with WWV quite easily. inserted into th e space between the display tubes fo r the hours and the minutes. However, the read abil ity o f the faceleaves so me thing to be desired , since there is The result was 12: 34 56 instead of 12 34only a narrow space betwe en the h ours and 56.minutes, and another space o f th e samewidth between minutes and seco nds . That is, The P200 I LED is ra ted by the manufac-an indicated time of 12 :34 plus 56 seconds turer at a maximum curre nt o f 40 rnA , andwould be displayed : 12 34 56. What is emits a reddish light at an intensity depend-need ed , obviously, is so me me ans of se pa-rating the hours and minute s from the , -- ,LEO BOARD ,---- -- ,RESISTOR BOAROseco nds. I \"'-'\" I I 2200.1\ 1/2 W I It would be a maj o r p roject , and probablysomewhat doubtful o f success, to try to I { I HEP 2 200;\ 112 W Imove the display tubes apart any appre ciable I '\::: I P2001dist ance to achieve this condition . I II The problem can be so lved, or at least Iimproved upon, by attacking it from another II Idirection with a relatively simp le modifi ca- I 1 HEP I I P20 01 IL -,I_tion. I It was done in my shack by mounting apair o f Motorola HEP ty pe P200 I Light L __ -' 2 4 vee Fig. 1. Schema tic use d in ad ding th e LED's to th e clock.50 73 MAGAZINE

The LED board is visible between the dis- play tubes for the hours and minutes. The resis- tor board is visible at the lower right hand corner of the chassis, directly underneath the right side of the seconds display tu be.ing upon the amount of current p assmg dress. The positive leads can be simply runthrough it. along the back of the top of the minute and second display tubes and down to the floor After experimenting with different values of the clock, where they are connected toof limiting resistors I finally settled on a the resistors.current of about 9 m A, flowing through a The resistors are mounted on a piece of2.2 kn half watt resistor. This combination circuit board about 2.5 em by 2.5 em in sizeyields a light intensity approximately equal which is secured to the same bolt whichto that of the numerals on the clock, holds down one end of the power transfor-although slightly redder in color, and is well mer.within the ratings of the LED. From this point a single lead runs to the The LED's are mounted on a piece of Source of voltage, about +24 V de, which isperforated fiberglass circuit board approxi- tapped by connecting directly to the ex-mately 2.5 cm long by 0.75 ern wide, and posed positive lead of the 1200 J1F filterare offset slightly so they assume a slantedattitude of about the same angle as the c apaci t o r.numerals. They are mounted vertically about Be Sure you connect to the right capaci-0'.75 ern apart. tor, as 230V is present on the other one. If The edges of the board were carefully in doubt, use a voltmeter.shaved down with a small file until it couldbe pressed into place between the adjacent The ground lead from the LED board isedges of the hour and minute display tubes. dressed with the positive leads until theyA drop or two of epoxy glue was used to connect to the resistor board, at which pointsecure the board, once positioning was satis- it separates and goes back along the top offactory. Be sure to position the board so the the chassis to a ground ·po int. Any exposedLED's are vertically centered with respect to ground point can be used, but I groundedthe numerals. the wire by connecting to the negative lead of the filter capacitor, since it is also The cathode leads of the diodes are exposed and convenient to solder to.connected together, and a single wire runsfrom this point to ground. In addition, a In use, the two LED's are lit at all timeslead runs from each diode's anode to its the clock is in use, and form a double dotlimiting resistor, both of which are mounted between hours and minutes. Their intensityon another piece of circuit board . is approximately the same as the numerals, but the color is slightly redder, although not Since this is entirely a de circuit , there is enough to be objectionable.nothing critical about the layout or lead ... WA\JKHVFEBRUARY 1974 51

Walt Pinner WB4MYL 7304 Lorenzo Lane Lcuisviile KY 40228 COOK A BETTER C RCUIT BOARD,. .one that fits YOUR parts!S o yo u saw a swell article in 73 ancies, the original drawi ng may be altere d Magazine yo u would like to b uild'? Of befo re t he board is coated wit h the resist course . being consistent with today 's tech- pai nt (airplane dope, fingernail polish. nology, most of these fine articles incor- etc.). Ho wever, if many of your parts just porate a print for an etched circu it board . wo n't fit, as mine often do n't, then design If you have never made your o wn board, you r own boa rd as fo llows.read on. If yo u have etched yo ur ow n, you have then probably enco u ntere d th e fol- Step #2'lowing d ifficulty - my parts WOll 't fi t theau thor 's board #*@%¢$ @. So read on Take a flat piece of styrofoam, available anyway . everyw here nowadays (packing mate rial, hobby or dime stores, or borrow the picnic Over the past several years I have used cooler lid). On the styrofoam lay a plain t he fo llowing procedure for alte ring circuit sheet of paper. Using the schematic of your boards o r even creating a completely new project, build the circuit by inserting the layout. It 's ' simple, does not req uire any co mpone nt leads th rough th e paper and special eq uipme n t and in many cases d e- into the styro foa m, in th e same manner signing a new board takes li ttle o r no more you woul d moun t parts o n th e board it sel f. tim e t han using the one suggested , T he end In most insta nces the physical placemen t result is a project to be proud of, no of the parts and the schematic layout will bunched up components, no messy lead be very similar. The major advantage of extensions and the darn th ing really lo oks this o peration is you may alter the size or pro fessional. shape of the final board to fix a box you already have o r fit a particu lar space Step # 1 requirem ent. Having selec ted a project, assem ble all Figu re I shows a flat schema tic ty pe the components befo re you. Compare your layou t which is not only neat, but should parts with the space allotted in t he author's you at some future date wish to modify it , circuit board layout. Most layou ts provided all parts are accessible . Should you wish to are fu ll size an d this comparison is simp ly a mi niaturize a circuit , the vertical mount ing matter of laying your pa rts o n t he d rawing. of pa rts may be utilized. As you are Assum ing t here are o nly minor discrep- construc ting yo ur circ uit, should an area of52 73 MAG AZ IN E

Clf'CU t- *MlS and remove the template. Check over the board for any unwanted spray or runs. If WITH l\"£LT P!:N any are noted they are easily removed with the wood portion o f a broken pencil. Do lWIAIRT!H< FsEcL.T. \"P\"E'N\"' no t attempt to use so lvent, as a fine film will remain and incomplete etching willFig. 1. Typical lay out on styro foam and paper, as oc cur.described in Step #2 above. Once the paint has dried completely , about 30 minutes (or hurry it along with athe boa rd become ja mmed, at th is stage it hair dryer), etch your board with any ofis a simple matter to remove the compo- the solutions commonly available at mailnents involved and reorient them to elimin- order houses. I etch in a Pyrex glass dish ,ate the problem. borro wed fro m the kitchen , and heated o n t he range to abou t 1500 • A co mb i na t io ~ of heat a nd gentle rocking will cu t the etc hing tim e by ab out 50%. Using su rplus board which generally has rath er heavy co p per , takes about 20 to 30 minutes.Step # 3 Step # 6 Now that yo u have simula ted the circuit No w that your custo m board is etched ,on the paper covered blo ck, usc a felt tip remove the remaining paint with a Brillopen to circle all the areas where part s are to pad and hot water. This clean-up takesbe soldered. Draw in the connecting foil only seconds and leaves a nice shiny circuitruns and any islands where leads from parts to go to work o n. In the interest of keepingnot mounted o n the bo ard are to be the board 's appearance new , before solder-connected. Should fo il runs have to cross ing I give the co m plete board a light coatmerely break o ne run and mark it for a of clear Krylon spray. No problem solder-jumper to be inst alled later. An alternate ing will be en countered as a result o f thisbut somewhat more co mplica ted method is spray and should you desire to markto etch the reverse side of the board to connec tio ns, values, o r o ther identificationsupply these crossing foil runs. o n the bo ard with a felt pen , these will also be protected.Step # 4 There is really nothing sacred abo ut Remove all the co mpo nents from the circuit boards, and no o ne ever said yo uboard and, using a hobby knife o r razo r must riddle it with holes for compo nentblad e, cu t out all the marked islands and mounting. I generally mount the parts o nfoil runs, as though y ou were makin g a the foil side, eliminating all the drilling. Ittemplate. As a matter o f fa ct you are looks just as neat and now you don't evenmaking a template. Take the paper tem- need a chassis. Several of my projects areplate and steam one side over boiling water circuit boards laying flat as a base with auntil it is limp, but not really wet. Imme- front panel made from the same sto ck (nodiately lay th e template o n th e blan k need for hardware as the panel may becircuit board stoc k. Ste aming allo ws it to so ldered in place) and a wrap-around coverlay flat and gives some degree of adhesio n. with front panel o verhang. Thin aluminum covered with stic k-on vinyl make s an at-Step # 5 tractive and inexpensive cabinet. Spray a light coating o f clear Krylon o r Well , that's the story. If you can sweet-similar material o n the template covered talk the XYL into letting you use her hairstock. Common spray enamel may also be dryer, range, dish , and nail polish, let'sused , but any notes you may have made o n make a board .th e template will no longer be legibl e.Allow 2 or 3 minutes for the paint to set . ..WB4MYLFEBRUARY 1974 53

Charles Townsen d WA4DCN 1440· 1 N o. Meridian Rd. Tallahassee FL 32303 A VARIABLE Q AUDIO FILTERT he selectivity of modern amate ur re- Q3. Since there are no w two out-of-p hase ceivers has beco me quite good in re cen t signals feedi ng amplifier Q3, its net outp ut isyea rs but there is still ro om for improve- severely reduced. The degree of cancellatio n,ment, especially with the bands as crowded therefore the selectivity, can be controlJedas the y are . The fo llo wing audio filt er was by the selling of R4 , whic h determin es thedesigned and built to imp ro ve the selectivity amo unt o f inverte d signal reaching the baseo f my Heath SB-303 , but ca n be used with o f Q3 . This pro ce ss occurs at all frequenciesany re ceiver provided it is reasonably stable. e xce pt the chose n resonant fre quency. AtT he filter' s bandwidth a t -6 dB, fera ce n ter resonance no inverte d signal will be passedfreque ncy o f 1 kHz, is variable from ap- by the twin-T network , allo wing the o riginalproximately 40 0 Hz to less than 50 Hz. T he in put signal to be amplified by Q3 . T hee ntire unit is solid state. requires no bulky filtered o u tput is then boosted by am plifiersL-C com pone nts, and is built as an external Q4 and Q5 to drive a small speake r orrece iver accessory. Cost of the project using p h o nes.all new components is abo ut $35 . Since it is possible to overdrive Q3. it isThe Circ uit necessary to have so me way to know when The filte r is a tuned amplifie r usin g the input level is correct. This is accom-inverse fee dback. Audio from the re ce ive r plished by sampling a portion of Q3's outputenters through e mitter follo wer Q I and is with meter amp lifier Q6 and rectifying it topassed o n to amplifier Q3. which inverts the drive a I rnA meter. The meter is calibra tedsignal's phase. Part o f this inverted signa l is by t he selli ng of R5 so tha t 4 V Pop at th ethen fed back to twin-T network , R I , R2, collector of Q3 read s 0.4 o n the meter. ThisR3 and CI , C2, C3. The particular network is just belo w the overdrive point o f thepresents high imp edance to ground at all tuned ampli fier.frequencies excep t its resonant frequ en cy,similar to a series tun ed L-C circ uit. T he Construction Not esunatt enuated signal next enters emitter fol-lo wer Q2, and witho ut fu rt her phase shift, is Mo st of the circu it (excl udi ng tra nsfor-added to the uninver ted inpu t at the base of mers) was constru cted on Vectorboa rd using press-fit terminals , but could be built o n a PC board with the accompanying reductio n • .• • .- ,-. -~-:\"l\"\" ~\"\":~r\"I'~ •• •••••••••••••••••••••••••••••• •••• • •• • • •• •• • • •• • •• •• • • • • • • • • • •• . ..... ... . . ..•'••••••••• •• • • •• • • • • • • •. ..' ., .'.,• • • ••• • • • .• • . ..... ... ' • • • '. , •• •• • •• . ' •• • • • The filter can be assembled [or rack m oun ting as sho wn or in its o wn box as a receiver accessory.54 73 MAGAZIN E

. - FEEOS ACK ,- <Iy ec4 701( ,. 22< , ,390 561( lOO K 8.2 K , \"¢)\" SE~LEC- TIVITY c: 02 02 41.U \" \" 0'.r 00' 00' , \" \". \".1 '\" '.'25v zov\"\" - LI NE TO JI ,iHONES RI 50 1( R2 50 K 0' 20< v.c . ., R'UU ',\" '\" \" 5OOl\"F ~K '\" \"0 lOO K ca 220 IOVDCR' voc 1.5K YO or'\" ,0< ~ j, .I~ •I? ' M'5.6KMET E R 115VAC en S\"R 25VAC '.' I \" \" .,3901( 330K 4 70 1( • 25V 0)f oz PO WER 5VQC lOO K SUPPLY lOOK ~fl r ~I st , / 1. 0 l' F ~\" INPU T ' .. 1\ 25V 0 6 Im A ,0< 680 1( '\" '\" y-~.n.~ r¥:.' '\"\"O ~~ ~08 ; IK 220 500/,: • V 2 ~ ~02 2 50V '00 \".e- ~~sOoIv'F - SET AT +15Fig. 1. Schema tic o f th e Varia ble Q Audio Filter. A l th ough i t: is designed aro un d a cen ter fre quency of1000 Hz, in forma tion is given in the text to mo dify the freq uency to suit any need. Q1 through Q6are GE-20 transistors, an d Q7 may be a GE- 14 or GE·28.in size. The circuit board and o utpu t tra ns- o ut to be just wide eno ugh to mou nt all theformer were h oused in a 7 x 11 x 2 in ch co n tro ls, me ter, and a sma ll speaker. T hechassis, whi ch was to o small to acco m- 150011 outp u t of the amp lifier was matchedmodate th e power transformer too, so it was to the speaker by using a 70V line transfor-mounted o u t board o n t he rear o f the chassis. mer co nnec te d at t he SW tap. T he heat sinkThe front panel is a ra ck pa ne l, which turned fo r the regulator transistor in the power • •Thi s vie w shows the assem bly on a piece of Vectorbaord. Th e size can be re duced considera blywith miniature com ponen ts and denser packagin g.FEBRU AR Y 1974 55

supply was later found to be unn ece ssary. the way may res ult in a regenerative ho wlThe use o f poorly matched capacito rs in the due to excessive feedback in the circ uittw in-T net wo rk will! result in a low-Q filt er. it self, even with no in put signal. This isCapacitors should be 1% silver mica for CI, normal, and the selectivity is too nar-C2, C3 , or th ey should be rnatched on a ro w to be useful anyhow (40 Hz or less).bridge. Do not atte mpt to substitute ceramic Under the right conditions the circuit willcap aci to rs . narrow down to a ridiculo us II Hz at -6 dB.Ca libration When tu nin g th e twi n-T, you will prob ab- ly find that the circu it will peak almostA scope is best for making fin al adjust- any where near 1 kHz, whic h mayor maymen ts but a VTVM will do . Disconnect the , not be the point of best selectivity. T he re-p ower sup ply o ut put an d switch on th e ac. fore, rock the receiver or generator dial asSet th e out pu t voltage at + 15V dc . Rip ple you tune for a peak in the outp ut. T here willsho uld be less th an 6 m V POp. Reconne ct the be o ne frequency which gives a significantlypo wer sup ply and disconnect the selec tivity larger output than any other. This frequencycontrol. Fee d in a I kHz tone from the is the one to adjust to.receive r or a genera tor and adjust the inputlevel co ntrol for 4V pop ou tp u t a t the Operationcollector of Q3. Adjust the meter amplifier Tunc in a signal in a noisy , crowdedto read 0.4 rn A o n the me te r . Preset th e t wo portion o f a CW ba nd wit hout using thepots in the ar ms of t he t win -T to 32K. filter. Set the filter's vo lume at 3 o ' clock andReconnect the selectivity co ntro l, set it at the selectivity at abou t 12 o'clock . Now tum12 o'clock, and alterna tely tri m t he pots in up the input level on the filter and retunethe t win-T for a peak at or near I kHz. In the receiver until the desired signal suddenly • peaks up in the filte r an d reads 0.4 rnA onmy filter the peak occ urred at 95 0 Hz asmeasured o n a GR 11 91 freq uency counte r. the me ter. Set the selectivity as desired, 100Advance the selectivity and repeak the Hz (2 o'clock) being a good sta rting place.t win-T , retuning the receiver o r genera tor to While peake d o n a signal, switch off thekeep o n the nose of the filte r's selectivity rece iver's speaker and listen o n the fi ltercurve. Turning the selectiv ity control up all instead . Tuning is quite sharp, peaking the desired station and severely attenuating allo r'\ ot her noise and adjacent QR M. To resume normal operatio n, reduce the filter's volume • -.I I\. - -6db ' 5 B- 3 0 3 setting and switch the regular statio n speaker BANDWIDTH' 4 OOHz\"0 F ILTER back on. This syste m will allow for switching BANDWIDTH ' 7 , H,., T WIN-T FI LTER rSB -303 I·F F ILTER fro m \"norma l\" to \"sharp\" selectivity with a 0 ( 400HZ CW) min imu m of effort . ..-, , ~ N O OUTPUT ZONE • Some operators may prefer a diffe rent EXCEEDS RECEI VER'S -, CW FiLTER WIDT H\"0 - aoee frequency of filter responses, such as 900 Hz inst ead of I k Hz. Or, perha ps filters fo r two· . 0 different frequencies are needed , as in RTTY conversion. If this is the case , the values of· 00 C I , C2, and C3 mu st be alte red using the foll o win g method .,J \ , -·60 -- , .,0 <0 2 0KHz Let R3 equal 16K. R 1 an d R2 are th en t wice this value. C3 is calculated so that at the frequen cy of resonance, its reactance -'.0 -.5 ,0 . ~ ,'0 , equals R3, o r 16 Kn. \" FR EQ UEN CY IN KHz C = 1/2rrfXc where Xc = 16 Kn , or more simp ly C = 1/0 . 1f where C is in mi cro faradsFig. 2. Graph showing the filter 's effect on the and f is in Hz. C 1 and C2 are each half of thebandwidth of a receiver wi th an internal 4 0 0 Hz value o f C3.fi l ter. . ..WM DCN56 73 MAGAZ IN E

ANOTHER BLOWN Joh n A . Carroll K6HKB /lFUSE INDICATOR 18 Ferguson Road Malden MA 02148FOR LOW VOLTAGEI n the March '72 issue of 73, W\lEDO th e resistan ce is R = (E - 1.2V)jl and the d escribed a method o f using in cand escent power dissipation is P = 12R . In an ac circ uit,lamps to detect blo wn fuses in low-voltage a ca pacito r or inductor may be substit ute d,equip men t. Light emitting diodes can do the with a reac ta nce equal to th e resistance given ab ove.same thing, using the circuit shown. T he The reverse d diode across the LED ismain ad vantages are small size, very lo w need ed in an ac circuit to short it during theindicato r curren t after the fuse blows, and reverse h alf of the cycle and prevent reversehigh reliabili ty . The d isadva n tage is cost. voltage from ap pearin g across the LED . While it isn 't necessary fo r de, it does se rve Sin ce LE D' s haven 't been heard fro m as insuran ce in case the circ uit is initiallyvery mu ch in ham gear, a few words abo u t installed backwards. In the rare case of a detheir charac teris tics are in orde r befo re sup ply o f unpredict able or changeable po-lo oking a t the circuit ry. larity, it would be possible to use another LED for th e protective diode , so that eac h Like rectifying diodes, LED's have a wo uld protect the o ther and one wouldnearly co nstan t fo rward voltage drop across always light , o r else place a single LED in aa wid e range of curre n ts (ty pically abo ut 4-diode rectifying bridge .1.2V). This means that an ex ternal resisto r isnecessary to con trol the curre n t when FR OM LOGICopera ting from a constan t voltage sup ply. POWER SUPP LYThe safe reverse voltage is genera lly o nlyabout 3V. Light is emi tte d on ly wh en \"\"LED +forward curren t is ap pli ed , so po lari ty must SEE TEX Tbe observed . T he negative termin al is usuallymarked with a wide lead , a color d o t , o r a Fig. 2. L ogic r eadout.notch in the rim o f the case. I' ve fou nd that3 mA will produce just abou t enough light Most industrial electro n ics deal ers carryto see when lo oking closely at the LED , suc h LED 's as the Monsanto MV50 or itswhile 20 mA will make a bright eno ugh glow pan el-mounting equivalent the MV5020.to draw atten tion in a well-lit ro om . T he These are priced in the 75 ¢ to $ 1.5 0 range .ma ximum safe cu rren t is in th e range o f Almost any inex pensive red-emitting LED50-100 mA. The operating cu rren t should sho uld work eq ually well . As for the reversebe ch ose n some whe re within th ese limits, pro t e c tion diod e, practically anythingcon sistent with th e needs of th e sit uation sho uld be satis fac tory, though a small siliconand the ma ximum safe cu rrent und er blown diode would have the smallest leakage. I fuse conditions . No socket is used . prefer th e 1N4 148 b ecause it 's availab le for as little as 8¢. The voltage ac ross the series resistor is thesu p ply voltage less the LED fo rward drop, so Ano ther use fo r LED's worth ment ioning is read out from logic circuits. They will run :- LED dire ctly fro m a logic gate and ne ed no special driver or po wer supply . +- -+ . . .K6HKBflFROM + MONITORED FUSE LOADPOWERSUPPLY _Fig. 1. Blown f use indicator .FEBRU ARV 1974 57

WHEN YOU BUY KENWOOD ...YOU BUYPRIDE, PLEASURE & PERFORMANCEPride in knowing that you own today's ultimate in state-of-the-art tech-nology ... pleasure in operating a rig whose day in, day out performance will----show you why the Kenwood name is world-fa-mous for reliability and value. Kenwood's superb • •':1• •solid state SSB transceiver i -;'~fi- 1S·900 - -~...•• • the ultimate transceiver. The promise of the too numerous to list. Its specifications are superb•transistor has been fulfilled. Here is the transceiver The TS-900 is unquestionably the best transceiveryou will want to own •.• whatever you have now, of its kind ever offered. The price •..• $795.00get ready to trade up. Its important features are far PS·900 lAC Supplv) $120.00. the DS-900 $140.00 18 520 Kenwood's go every place • . .. do everything transceiver The new TS·520 is the transceiver you have wanted. but could not buy until now. It is a non-compromise, do everyth ing, go everywhere 5 band transceiver for SSB or CW that performs equally well at home, in an automobile, airplane, boat or trailer. The TS-520 features built-in AC power supply. built-in 12 volt DC power supply, built-in VOX with adjustable gain delay and anti-VOX. The price ••••••••••••••••••••.. $599.00 AM.N and FM. The price $439.00 The T·599A Is mostly solid state ..• only 3 tubes,The R·599A Is the most complete receiver ever has built-in power supply, full metering (ALC, Ip,offered. It is solid state, superbly reliable, smalland lightweight, covers the full amateur band RF output and high voltage), CW·LSB-USB-AM••• 10 thru 160 meters, CW, LSB, USB, AM, operation. The price $4S9.00See the Kenwood line at the following dealers: CALIFORNIA Communications Headquarters, San Diego• Gary Radio, Inc., San Diego • Ham Radio Outlet, Burlingame. Henry Radio, Anaheim. Henry Radio,Los Angeles. Sequoia Stereo, Arcata. Webster Radio, Fresno. FLORIDA Amateur Electronic Supply,Orlando. Amateur-Wholesale Electronics, Miami. IDAHO United Electronics Wholesale, Twin FallsILLINOIS Erickson Communications, Chicago. Klaus Radio, tnc., Peoria. INDIANA Graham Electronics,Indianapolis. Hoosier Electronics, Terre Haute. Radio Distributing Company, South Bend. IOWA HobbyIndustry, ccuncu Bluffs _ KANSAS Associated Radio Communications, Overland Park _ LOUISIANA Trl-ontcs, rnc., New Orleans _ MARYLAND Electronic International Service corc., Wheaton _ Professional Elec-tronics, Baltimore _ MICHIGAN Electronic Distributors, Muskegon _ Radio Supply & Engineering Company,Detroit _ MINNESOTA Electronic Center, Minneapolis _ MISSOURI Ham Radio Center, St. Louis _ HenryRadio, Butier _ MONTANA Conley Radio Supply. Billings _ NEW JERSEY Simon Side Band Company, OakRidge _ NEW YORK Adirondack Radio Supply, tnc., Amsterdam. Harrison Radio Corp., FarmingdaleNORTH CAROLINA Vickers Electronics, Durham _ OHiO Amateur Electronic Supply, Cleveland _ Commu-nications World, Cleveland _ Queen City Electronics, Cincinnati _ srepco Electronics, Dayton _ OKLAHOMADerrick Electronics. Broken Arrow • Radio, tnc., Tulsa. OREGON Portland Radio Supply, PortlandPENNSYLVANIA JR5 Distributors, York. Kass Electronics, Drexel Hill. SOUTH CAROLINA Accutek,tnc., Greenville. SOUTH DAKOTA Burghardt Amateur Center, Watertown. TEXAS Douglas Electronics,Corpus Christi. Electronics Center, rnc., Dallas. Industrial Distributors, Dallas. Ed Juge Electronics, rnc.,Fort Worth _ Madison Electronics, Houston. UTAH Manwlll Supply Company, Salt Lake City _ WASH-INGTON Amateur Radio Supply Company, Seattle _ WISCONSIN Amateur Electronic Supply, Milwaukee Prices subject to change without notice.58 73 MAGAZINE

o o• IS Ine..u~~ finest qualit~.u~~ best valueTempo 's Commercial Line VHF transceiv- - •ers offer commercial performance atamateur prices. Compare these transceiv- TEMPO /6N2 -ers with any other available. Comparetheir performance, their quality of con- The Te mp o 6N 2 meets th e demand f o r a h igh po wer s i xstruction, their ease of maintenance, and mete r and tw o me te r po we r am plif ier. Us ing a p ai r ofthen compare prices. Your choice will Ermac 8874 t ubes if provides 2000 w atts PEP i nput onhave to be Tempo. ~SB a nd 1000 w att s in put on CW and FM . Completel yTEMPO/CL146 s-t t-co ntatneo i n one small desk mount cab inet wit h in-The CL-146 offe rs ope ratio n on the 146 MHzamateu r ba nd. The price includes a mic ro- te rnar soli d sta te power su pply , b u ilt in bl ower a nd AFphone, power cord, mountin g bracket and on epai r of c rys tals. A full line of accessories is also rt; iative p ow er i nd icalor. $695.00ava ilable.• 12 c ha nne l ca pa bility . 13 wa tts or a power TEMPO/bubsaving 3 watts . All so lid sta te, 12 vac • 144 So m uch l o r so lillie ! 2 walt VHF /FM ha nd he ld . 6 Ch a nnel c a pa bili ty, so li d sla te, 12to 148 MHz (any two MHz wit ho ut retunin g) VDC , 14 4- 148 M Hz (a ny tw o MHZ) , incl ud es 1• Supplied wi th one pai r of c rysta ls . RF out-put meter, S-mete r, re ceiver detecto r meter p a ir of c ryst a ls, b uilt- in chargi ng termi n als fo r• Provisi on s for externa l osci llator • Monito r nr-c ao c ells, g-mete r. battery level me te r.feature. Audio output at fro nt panel. Internal te le sc op ing whi p an tenn a , interna l s pe a ke r &speaker . The Price : $299.00 microphone $199 .00TEMPO/ TEMPO/TPLCLZZO high po_e..As new as tomorrow! The superb CL-220 em-bod ies the same gene ra l specifications as th e liD BlDpIlUe...CL-146, but operate s in th e frequency range of .POWER220-225 MHz (any two MHz without retuning). MODEL POWER OUTPUT (m in) \",At $329.00 it is undoubted ly the best value NUMBER INPU Tavailabl e today. T PL 100 2 -3 510 2 E>W 10 0 · 13 E> W 2M 2M TPL 1002·3B 1·3W BOW 2M BOW 2M TPL802 5W BOW 2M 2M T PL802B 1 to 3W 35-55W 2M T PL 502 5 10 15W 45W 440MHl 25W 440MH l TPL502 B 1 to 3W T PL 2 52·A2 lW 12W 440 M H l 3 0W T PL445·10 1 102. 5W 30W T PL4 45-30 4W T PL4 45 ·30B lW rcp 1:: \ Control Head Prices subject 10 change without noticeAV AILABLE AT SELECT DEA LERS THROUGHO UT THE U.S. 59FEBRU AR Y 1974

-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --1 Bud M ichaels WB2WYO 71 3 High Street Victor NY 14564 BUILDING WITH TEN -TEC MODULES A 40/20 METER QRP CW TRANSCEIVERW hat's this - an other QRP trans- pa t ie nce to o pe ra te low power successfu lly. ceiver'! The magazines are full of So , if yo u are jus t gett in g starte d in hamthem these day s. What's the sudden interest radi o , o r if y our frus tra t io n level is low,in flea -power o pera tio n? perha ps yo u had best leav e QRP alone for a wh ile. QRP has indeed mad e a strong co me bac k.And there are good rea sons. Simple but T en-Tee Cor po rat io n o f Sevierville , T en-efficient transistor circ uits mak e po ssible nessee , offe rs a lin e o f so lid-sta te modulesco mpac t rigs that appeal to the traveler a ndcam pe r. Stable vfo's are replacing th ose Complete QR P station in a box. Key, headph ones,o ld-t ime ro ckbound peanut whistles we used an tenna an d logbook fi t in to deep cover on au thor'sa whil e back. ( Re me mbe r the 3V4 and a transc eiver. T wo lan tern ba t teries fi t alon gside lo ud-handful of crys tals? For every ro ck you h ad , speaker, un der bottom panel.th ere were a dozen guys o n the sa mefre q ue ncy. eac h running a gallon !) And there is another rea son. More andmore fellows a re fin ding that y ou ('anco m mu nica te wit h o nly a fe w watts. Andwhat's more , it 's fun an d challenging. Whenthe band is o pe n, and y ou get a 589 fromthat OH in Helsinki, and y our input power iso nly 2 W, well, wha t more is there to say ? But QRP isn't fo r everyone, and be fore Ilead you astray , it's o nly fair to p oint ou tthat th e calls-vs-con tac t ratio can be prettylow, especially during the cro wd ed eveninghours. It takes skill , special te chniques a nd60 73 MAGAZINE

that le ts yo u put to gether QRP CW tran s- PARTS LISTce ivers cove ring 80 thro ugh I S me ters. Yo uca n buy their MR I kit wit h whic h you ca n Transceiverma ke a 2W rig coveri ng 80, 40 , 20 or 15me ters. O r you can buy their basic modules M O D U L ES: (O rder from T en-Tee , tn c ., Sevierv illeand build a 5 walter for 4 0 and 20 meters. TN 37B62)Eit her tra nsceiver ca n be powered from 12 V VOl Oscillatorlan tern , moto rcy cle or auto ba tte ries. Of MX 1 Mixercou rse, you can also buy these rigs alrea dy AA 1 Au dio Amplif ier A C6 20 meter d oubl e & sidetone osci llato r • T X 2 40/20 m eter tr ansmitterbuilt a nd in a hand some cabi ne t , but if you Tl - 1000 ohm to 8 ohm rmnrature ou tp utlike t o tailo r your rigs to your o wn particu- transformer (R adi o Shac k N o.1380)lar sty le, the modul es are th e way to go . R1 - 220 o hm %W R 2 - 33 00 ohm %W For my ca mp ing trips I chose to build a R3 - 25,000 vo lu me con t ro l with on /off swi tc h5W transceiver t o cover 40 and 20 meters, (Radio Shack No.0941but th e general co nst ruc t io n tips a nd acces- R4 - 6 .800 ohm %Wsories described h ere ca n be ap plied to the C l , C3, C4 - 365 pF vari ab le (R adi o Shacko t h er rigs possible u sin g th e Ten-Tee No.1344. Lafayette No.110341modules. My rig features o ne-k nob band- C2 - 560 pF mi caswit c hing, CW side to ne , a b uilt-in an ten natu ner a nd SWT bridge (a must fo r those C5 - .22 IlF 3 5Vra ndo m le ngt h ante n nas), dial lamp s for C6. C7 - . 1 IlF 35Vn igh tt ime operatio n and a loudspeake r. Ina d dition , I selec te d a cabi ne t wit h enough C8 - 82 pF m icaro o m to house the batte ries, headphones, Speake r - 2 \" diamete r 8 ohm (R adi o Shac kkey , logb oo k , scra tc h pad a nd o th er o dds No.2451a nd e nds, tru ly giving me a \"sta tio n in a Dial - R adi o Shack N o.3 88 (5\"), Lafay ettebo x. \" No.25660 14%\") Cabi ne t - Gle nwood Sales, 594 H agu e St. ,Circuit Description R ochester N Y 14609 5 1 - 5PST (part of R31 A blo ck d iagram of th e transceiver is 52 - Fi ve p ole, two p o smon rotary (M all oryshown in Fig. I . The re ceiver utilizes the 3 263J o r 4M2323 usabl e)sy nchro dy ne principle , a lso kn own as dire ct 53 , 54 - DPDT rocker swi tc hes (R adi o Shac kco nversio n. A b fo, o pera ti ng at th e receiving No.030 kit of two)freq ue ncy, b eats with th e in coming signa l in LMP1 , LMP2 - 6.3V panel lamps, No.47a p ro duc t d ete cto r. The resu lta n t freq ue ncyis a n audio signa l which is processed by a o u tp u t of the produ ct detector estab lish eshigh-ga in audio amplifier to d rive the lo ud- th e selec tivit y o f the receiver , which isspeake r or head phones. A filter in the a ro u nd 2 kH z. The se nsit ivity of this simp le receiver is surprisingly good , an d it ap pears PRODU CT AUOIO .-J to be co mparable in perfo rma nce to medi- AMPL ifIER u rn- p rice d co m mu nica tio ns receivers.r-r- OE TE CT OR --, In the tra nsmi tter po rtio n, th e bfo fu nc- Rev 20hlETERS .'0 tions as a vfo, and you tra nsrnif o n the sa me fre q ue ncy you rece ive on . A buffer stage '\"T o\ 8 \" FO isola tes the vfo fro m th e driver an d power a mp lifie r. ( For 20-me ter o perat io n, a doub- OF 4 0ME TEAS ler circ u it is switc he d in between th e buffer a nd the driver.) The o utput co mprises aA~PL IF IE R COUBLE R push-pull power a mp li fie r feed ing a pi n et- wor,k de signed to work into 50- 75!J. loads. F j g. 1. Block djagram The antenna tuner and swr bridge circuits were taken fro m various articles in recent magazines. The tuner com prises a tapp ed t oroid coil an d a single 365 p F variable ca paci tor. The swr bridge also u ses a t oroid coil t o boost t he sensitivity t o provid e ade qua te meter deflection at these low po we r levels .FEBRUAR Y 1974 61

I\" a , , ~u •6 0 -If- •• i1 ,~ L -u• •- Ti ,.,- = >0 \" ,w•~ r*+ > u~ N •~ ··'I~\"'\" u ~ L , •\".~\" ~\"\"~ • ••- w G~'i\"\" ~ (f ~:.- • L -~• •• -t''- a • ~ 0 \"0 - •\"w • •N •0 u L [@• •0 w •u• • 0 N N N 0 w ------I1L- •\"u % -0 ~•f- 0 \"•N L U [@ L •• •N • hL -.~••- • u- , 0 W w ~ L 0 •U • 00 u ,. ,~•~ ~ ••N \"u • rOO . <w. , >- •\"-, •\" ~Q m -, N iii \"~t. - •~l •w%%%W< •\"% ~ Fig. 2 Widng diagram for transc eiver.62 73 MAGAZIN E

CONCORD Y2\" VIDEO TAPE RECORDERS NOW Exclusive sale to licensed Amateur Only $350 $400-While they last- $ 10%\" VTR (was $1050)%\" VTR/solenoid operated (was $1295)Service ManualSPECI FICATlONSRECORDING SYSTEM: Helical Scan, dual rotating heads (long-life pressuresintered ferrite), 12in.lsec., 30 frames/sec., 2 fields/frame. VIDEO INPUT: 1volt POp, 75 ohm unbalanced, composite video, sync neg. VIDEO OUTPUT: 1volt POp, 75 ohm unbalanced, composite video, sync neg. HORIZONTALRESOLUTION: Better than 260 lines. VIDEO AMP. FRED. RESPONSE: 2MHz at higher than -6 dB . SIG/NOISE RA TlO: Better than 40 dB. AUDIO FRED. RESPONSE: • 50-12,000 Hz. POWER CON- SUMPTION: 80 watts. RE- CORDING TIME: 40 min. DIMENSIONS: 16%x16%x10 :. WEIGHT: 60 Ibs. ACCESSORIES INCLUDED: Empty reel, monitor cable, power cord, splicing tape.CONDITIONS OF SALE:These video tape recorders are sold as new or factory reconditioned. Shouldany operating failure occur during the first 60 days after purchase due tomanufacturers' defect, the VTR will be repaired or replaced at no cost to thepurchaser (except shipping charges), by Concord Communications Systems ofJacksonville. Check with order. Shipped freight collect.CONCORD COMMUNICATIONS SYSTEMS OF JACKSONVILLE 869 Townsend Blvd. Jacksonville, Fla. 32211 Attn: Jerry Anderson W41QTWatch for our ad next month featuring limited quantity specials on thefamous Concord vidicon cameras including their hand-held 2/3\" separatemesh view-finder camera. If you can't wait, call Jerry at (904) 724-6844FEBRUARY 1974 63

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -1 Reference s to articles con tammg details co rrec ted by su bstit u ting a 365 pF o r 4 0 5o f the sy nch ro dy ne principle , basic Ten-Tee pF capa cito r th at o pe ns clo ckwise.tran sceiv ers and th e o ther circuits are provi- A wire is wrapped arou nd th e MOSFETd ed at th e end of the article. lead s o n th e mi x er bo ard fo r prote cti onConstruction against voltage spikes which may occur dur ing co nstruc tio n. Be sure yo u leave this Connectio ns are made to so lder pins o n wire in place while you construct the rig. Remove the wire prior to opera tion, afte r allthe boards, which are coded for easy identi- soldering is co mplete .fica tio n. T he boards come packed with In retrospect I fou nd the dial lam ps to bespacers fo r mounting, aligning to ols ( whe re a nonessential additio n. Howe ver, shou ldrequ ire d) and data shee ts giving the schema-tic of the board and signal spec ificatio ns. you decide to use lights, keep in mind th ey It is do ubtfu l t hat you will want to draw mo re curre nt than do es the receiver !duplicate my cabine t layout , so I won't go For th is reason I inclu de d an on /off swit ch just fo r the ligh ts, to keep fro m de pleti nginto t he nitty-gritty details of chassis d imen-sio ns. e tc . - the photos give you a good idea the lantern batteries. I had never wound to roid coils before , soof my particular constructio n . Placement of it was an interesting learning ex perienceboards with respect to o ne ano ther is not makin g the coils for the ante nna tu ner andcritica l, bu t co mmo n sense sho uld be used to the swr bridge. It' s really very simple. Take a prevent unnecessarily long lead s, especially short length of wire of th e size you will be from the boards to th e ba ndswi tch. The vfo usin g for th e coil, and wrap o ne turn arou nd bo ard must be mounted as rigidly as po ssib le the co re. Unwind the wire and flatten it o ut , for frequency sta bility . then measu re its length. Multi ply th e length The variable capacito r that co mes moun- by the number of turns, and add a few ted o n th e VO I board o pens co u nterclock- inches for safe ty. Place the toroid co re in the center o f this length o f wire and begin wise. If you couple it to a vernier dial of th e winding the turns, carefully forming each typ e sho wn in th e photo s, the lower fre- turn around the core snugly by hand. When quencies will be at the right hand side, and you have wrapped one-half the number of the higher frequencies at the left , contrary turn s, begin with the o the r end of the wire. to normal practice . If you want the frequen- cies to be in keeping with the \"logical\" Be careful not to kink the wire. This rotation o f th e kno b, this can be easily technique redu ces th e number o f twist s and- Two fron t views of the transceiver, one showing battery compartmen t behin d loudspeaker panel. No te how panel space is conserve d by placing SWR meter with in dial assem bly .64 73 MAGAZ INE

turns on the wire , and makes the o verall job ante nna to serve as a dummy antenna and,easier. In th e case of the an te nna tune r , taps with the swr meter co n trol at mid range,are made to th e coil using stiff co p pe r wire close the key and adjust the tune and lo adwhich is solde red to th e l l-p osition rotary con tro ls for an ind icatio n o f rf on the meter.switch. T his p rovid es th e mechanical mount- If you get an indication , fin e and dandy.ing for th e coil. Leave th e t ransmitter for now, and let 's calibrate the little fellow. The parts fo r th e swr bridge should belaid o ut as sy mme trically as possible fo r Calibrationaccurate results. The toroid transformer pro-vides more th an su fficie n t drive fo r the You can use a commu nicatio ns receivermeter, which in my rig is a 500 jJA move- for calibratio n - o ne whose calibra tion youment. Once th e brid ge is built and wired in ca n trust - or a signal generato r. The follow-pla ce, it mu st be nulled ; this is covered later ing calib ratio n procedure is based o n using ao n in the article. r ec e iver.Testing Chec k th at the tuning capacitor o n the vfo board is fully meshed wh en th e vern ier Once WIfing IS comp lete, remove t he dial pointer is at zero. Pla ce the transceivershorting wire from around the MO SFET.nn bandwit ch to 40 meters, then set the cali-the mixer board. Co nnec t th e battery and brating receiver' s dial to exactly 7.0 MHzante nna and pla ce the band switch , to 40 and turn on th e transceiver. Using th e plasticmeters. With the mode switch In RECEIV E, alignment to ol that came with the vfo board,turn th e unit on and peak the receive co ntro l care fully place it in th e metal can on thefor best reception . Swit ch to 20 meter board , down past the first slug (there areoperation and repeak the receive con trol; t wo slugs - the top o ne is for 80-me ter use).yo u will notice it is a bit tou chy o n .i this Slo wly adjust the bottom slug until you hearband , but you should have no problem in the bfo signal in th e co mmu nicatio ns receiv-getting good recep tion on 20 meters. er's speaker. You will be amazed at how stro ng th e radiatio n o f this little oscillato r is! Sin ce you are probably itching to see Adjust th e slug for zero beat and mark thewhether the transmitter sec tio n works, co n- dial face with a pencil.nect a 5 watt non-inductive load to theSWR BRIDGE VOl (VFO) MXI 10101 Ace ANT. TUNER -----(MIXER) _..-(AMP) (DBLR) , ~ ,.\" 20M TRIM 40M TRI SIDETONE CONTROLSTwo views sho win g placement of Ten-Tee mo dules in th e author 's un it. Thumbn u t above external 1 2 Vjack is groun d term inalFEBRUARY 1974 65

TO AN T. peak the coil with the transceiver set at 14..)50 MHz; t he setting will hold for theFR OM LI Cl CW po rtio n of the ba nd .XMTR To null the swr bridge , use the dummy DE DIRECT TO ANTENNA load , and tune th e transmitter. Adjust t he bridge for full-scale deflec tio n in FWD.Fig. 3. Sch ematic of an tenna tuner. Switch t o REF an d adjust the trimmer capacitor at the inp u t end of the bridge (C l) PARTS LIST for a null on the meter. Temporarily un- solder the input and output to the bridge Antenna Tuner and reverse the m, then null C2, with theL 1 - 30 turns N o.20 ename led w ire over Am id on switch in FWD. (Don't lose any slee p if you can't get a perfe ct null; reme mber you areT-1 30·2 toro id co re (A midon A ssocia tes, 12033 looking for relative fron t-to-back read ings.)Otsego s r .. N . Hollywood C A 9 160 71. Taps every 3 Power Suppliesor 4 turns. Space t urns evenl y . The transceiver requires a 12V powerS l - 11 p ositi on rotary switc h (M allo ry 4 M 21111) supply. Current drain in receive is abou t 30C l - 36 5 pF varia ble (A adi o Shack N o.1344, rn A, and in tra nsmit , can run 480 rnA. YouL af ay ette N o.ll034l can use a pair of 6V lantern batteries in Now, by moving the calibrating receiver's INPUT TI OUTPUTdial, a divisio n at a time (the increment is up TO ANT.to y ou - I u sed every 10 kHz), and position- FR OM \" #; ~ CI VJing the transceiver dial until you get a zero xMTRbeat in the calibra ting receiver, yo u can \" CRI CR2 R2mark the transceiver dial from 7.0 to 7.3MHz. Repeat th is operatio n fo r th e 20-me ter .band, keeping in mind that the frequencysprea d is one-half o f the 40-meter display \"1 1• eRFC = C 04(you're doubling the fre quency, re me m-ber?). If you are lazy , you can transfe r the IBRQE I . / FWDcalibratio n marks from the 40-meter dial tothe 20-me te r dial, kee ping in mind that 7. 0 1 51will be 14.02 and so on. (METER] R3 ~~Tuneup and Adjustment Fig. 4. Schematic of SWR bridge. With the dummy lo ad in place , switch to PARTS LIST20 meters and tune the transmitter formaximum rf output using the TUNE and SWR Br idgeLO AD controls (make sure the anten na Tl - 6 0 turns No.3 0 enameled wi re over Amidontuner is out o f the circuit ). Don 't keep thekey down fo r p rolo nged periods o f time ; just T -68-2 toro id core . Cr o se wi nd the t urns . Prima rye nough to ge t a reading. Adjust the trimmercapacit or nearest to the output transistors is two turns N o.2 2 or 2 4 hook up wi re wound overon the transmitter b oard (TX2) for ma xi- cente r of secondary .mum rf outpu t on the meter, maintaining C l C2 - 1.5-7 p F cera mic trimme r ( Lafayetteresonan ce with th e TUNE an d LOAD con- N o.68386 mi ca u sabl e)t ro ls. Switch to 40 me ters and adju st the A1 , A2 - 120 ohm Y2WTUNE an d LOAD contro ls for maximum rf CR1, C A2 - 1N 3 4 A or equivalent (Radio Shacko ut put, then adjust th e trimmer on T X2 No. 8 21 for p ack of 10; se lect tw o t hat matc h th efarthest from th e output transistors fo r closest) .maximum rf. C3, C4 - .0 0 5 J1F disc type C5 - 330 pF cera mic or silver m ica Switch back to 20 meters and adjus t the AFC - 1 mH chokeslu g in the coil o n the AC6 d ou bler b oard Sl - SPOT (U se OPOT Radio Shack rocker;for maximu m rf o utput. For CW opera tio n, N o. 0 3 0 for kit of two) A3 - 25,000 ohm li near ta per con t ro l ( Radio Shack No.0941 Mete r - 50 J1A to 1 m A movement (Lafayette 500 /lA N o. 5036 1 a good size)66 73 MAGAZINE

R-X NOISE BRIDGE -.-• '\" Mo torcycle batteries make good portable powe: • Learn the truth about your antenna. supplies. Two 6 volt, 2 amplhour units such as thi: • Find it s resonant frequen cy . can fit into case along with a small ba ttery charger • Find R a n d X o ff- resona nce . Care must be taken to keep batteries upright tc • Independent R & X d ials greatly simplify prevent' acid spillage. t uning beams, arrays.series or a 12V lantern battery and get • Com pact, li ghtwei ght , battery operated .pretty good performance from t hem. But it • S im p le t o us e. Self co nta ined.is highly reco mme nd ed that you use a power • Br oadband 1-1 00 M Hz.source t hat presents a \"stiffer\" lo ad to t he • Free broch ure on requ est .rig, such as an automobile battery or motor- • Order direct. $39.9 5 PPD U.S. & Ca nadacycle storage battery. These sources will go along way in preven ting un wan ted deviatio ns (add sa les t ax in Calif.lin supply voltage and th e possibility ofchirpy signals. You can buy two 6V 2 PALOMARarnp/hr batteries for a sma ll Honda motor- ENGINEERSbike from Sea rs or Montgomery-Ward fo raround $4 each. T he batteries are sma ll BOX 455, ESCONDIDO, CA 92025enough to fit into the cover of the cabine t Iused, along with a small charger. SUPER CRYSTALAntennas THE NEW DELUXE DIGITAL T he built-in anten na t uner will let you SYNTHESIZER-!!-F.RO-M, FPload a varie ty of radiators. I often use just a65 ft long piece of wire, tying o ne end to a MFA·22 DUAL VERSIONlength of nylon builder's twine and a rock, Also Available MFA·2 SINGLE VERSIONand tossing it in to a t ree . By tu ning thetransmitt er , watching the FWD and RE F • Transmit and Receive Operation: All unitsreadings, and adjusting the La nd C, a bit at have both Simplex and Repe.ter Modesa time, you can usu ally get a good rna tc hand make worthwhile co ntacts. But you may • Accur.te Frequency Control: .000 5% ac-find the rig is \"hot\" with rf, and to uchingthe case may detune the rig! curacy • Stable Low Drift Outputs: 20 Hz per degree A better solutio n to the ante n na problemis to use a simple trap dipole covering 40 and C typical20 meters. The imp rovemen t over the longwi re justifies t he extra wo rk involved in • Full 2 Meter Sand Cover••e: 144.00 to 147.99setting up such an antenna. Of course youcould also use a vertical, such as the 14AVQ. MHz. in 10KC step'sas long as you use a good ground ro d or • Fast Acting CirCUit: 0 .15 second typical set-make a set of radia ls. t1ing time FEBRUARY '974 • Low Impedance ( SO ohm) Outputs: Allow long cable runs for mobiles • Low Spurious Output Level: similar to crystal output • PRICES R- P.. Electronics M FA -22 $27 5.00 M FA-2 $2 10.00 Box 1201 B S h ip pi n g $3. 0 0 Champaign, IL 61820 SEND FOR FREE DETAILS 67

MORE RANGE .•• Operating Tips with NO NOISE You will learn very quickly that it takes a ~o\l. ~\.\. bit o f p atience and a slightly different operating techniq ue t o be a successful Q RP tIIO~\\.~ \"l\\1S man. Experie nce has proven it's better to answer a CQ than to call one yourself. You CU STOM SYSTEMS will usually do b etter wh en the band isn't KITS' ACCESSORIES too cro wde d, and before the noise level gets up . My best operating has been early mo m- / ing through late aft ernoons. And with so many transceivers o n the air th ese days , if ELIMINATE IG NITIO N NOI SE you tune to th e high-frequency side of the other fellow 's signal, y ou will establish the ELECTRO· SHIELD ~ correct freq uency offset so he will be able to hear you without having t o re t une his,..-,:;;;:~YO~UR ENGINE receiver. FROM On 20 meters, y ou may hear foreign broadcast statio ns all over the band, regard- For less o f the position of the main tu ning dial. This is due to overloading of the simple FREQ. receiver front end. and ca n be reduced bv care fu lly pe aking the RECEIV E co ntrol. If STABILITY t hey still lea k t hro ugh, and adjus ti ng the ante nna tun er doesn't attenuate them in to 0'Depend on JAN Crystals . th e noise level , yo u ma y need a trap in the antenna lead to the receiver. I've been able Our large stock quartz t o peak up t he con tro ls so that whil e thecrystal materials and components assures Fast BCI is st ill t he re, it is far e no ugh d own in dBDelivery Irom us. so as not to bother my o peratio n. CRYSTAL SPECIALS One last co mme n t. Please use tact wh en you rece ive better signal reports fro m fel-2·METER FM for most Transceivers ea . $3 .75 lo ws running 100 times the pow er you are, 144- 148 MH z - .002 5 T a l. t ha n you give them. They'll most lik ely call 4.50 you a liar whe n yo u repe at for t he third tim eFrequen cy St andard s that you are o nly running a few watts in put. 4.50 It's just that they haven't learned yet that 10 0 KHz ( He 13 lU l y ou can get o ut wit h you r little flea power j ob almost as well as they can ! 1000 KH z (He 6/ U) A special th anks is in orde r to Mr. J ackAlmost all CB Set s . Tr . or Re c . 2.50 Birchfield o f T en-Tee, Inc. , fo r his invaluable (e e Synthe si zer Cryst a l o n requ est) tec h nical assista nce, and to Mr. Cou rt Packer for his photo graphy .An y Amateu r Band in FT -243 1. 50 .. .WB 2WYO(80·meter . $3 .00 - 160- me te r n ot ; p... .1d) 41 0r 5.00 ReferencesFor 1st cla ss ma i l. a d d 20c p er c rys ta l. For Equ ipment Report - Ten-Tee PM 2, J une 1970Airmail. add 251: . Send che c « or m on ey orde r. QST (DeM aw)N o deal ers . pl ea se . Direct Co nvetsion - November 1968 QST (Hay- ward, Bingham) CRYSTALS Division 01 Bob Whan Synchro dy ne De tectors, April 1969 QST (DeMaw) & So n El e ctr oni c s . In c . Antenna Tuner - Windowsill Vertica l, Jun e 1967 2400 Crys ta l Dr ive QS T (McCoy) Fl. M yer s . Fl ori da SWR Bridge - QRP Console, September 197 0 QST 33901 (De Maw) All Phones (813) 936-2397 Toro id Coils \"The Whole o f the Doughnut\" , JuneSe n d 10e fo r ne w ca talog wi th 12 OSCill ator 1967 73 (Klein)ci rc uits an d li sts of tr eq u en ci es In sla ck 73 MAGAZINE68

Bob Banin gton W6JDD 1087 Hewitt Drive San Carlos CA 94070 r'\ '\I .JIncrease y our average talk-power with this simple device.L ike a \"Mini- Linear\" for u nder te n Where d o you star!'! Comb through th e bucks? That would be almost some- past two o r three years of articles in t he various ham publications if you like. But ifthi ng fo r nothing, now, wouldn't it? Of you'd prefer to make it a little easie r oncourse you can't build a li near for that price yourself, an d inexpensive. play arou nd wit hbu t you ca n dramatically increase the effec- the circuit shown below. It has wo rkedtive ness of you r single sideba nd signal at low won de rs wit h Swan's, S BE's and many o thercost , wit h a li tt le care fu l experime ntat io n, t ra nsceive rs.How? With speech processin g - ca ll it pre-amp lification with clipping, co m pression - The basic circ uit is prett y simp le andwhatever yo u will, the name of th e ga me is stra igh tfo rwa rd: the correct use an d adjust-higher average level, increased in telligibil it y me nt of it, not ne cessaril y so. Here are theof commu nica tio ns. There have bee n allkinds of circuits publishe d fo r accomp lishi ng guide ru les: whe n the unit is properly aidi ngt his . The secret though, whatever approachyou use, is to do p lenty of experimenting for your average talk -power level. an rf b rid gebest results tailore d to y ou r part icu lar voice, on forward power o r a wattmeter will clearlyyour microphone, your exciter. \"ha ng up,\" like d elay ed A VC actio n o n the \"S \" mete r reading of a strongly received You can 't do this blind folded, any more signa l. Your \"Ch rist mas t ree\" pattern on athan y ou could expect to repair a co mp li- sco pe will demonstrat e th e difference, to o.cate d piece o f elec tronic gear with a wad o f And a brother ham can co n fi rm th is o n hischewing gu m. But t he k ind of tools youneed are not t ha t diffi cult to come by . . . .,\"S\" meter at a distant receiving p oint.and yo u may have so me of them already on YOCh and in the shack : a go od output meter (rfbridge or wa ttmeter); a mo nito r scope; and a 2 .8Kpair of good ears, prefe ra bly be lo nging to anunprejudiced frie nd in the ama teu r frater- t---, OR' 0.1 JlFnity. Better y et, ins tead of so mebo dy else'sears, why n ot a tap e recorder? You d on 't ~:j-1f-14M f) ,22 eR' '\"have to argu e with it . .. it is up to y ou to .01 )IFacce pt or reject t he reco rder's co m p lete ly HEP ~4 \"\" E--o0.1JlFunbiased ju dgme n t ! AUDIO 1~ OUT CRI, CRi!-IN34 (PREFERRED) or CO2 IN270, IN~38. HEP 1~6. Fig. 1. W6 JDD's au dio preamp comp ressor .FEBRU AR Y 1974 69

CFP ENTERPRISES You can control the degree of compres- sion to some extent by setting the mike level 866 Ridge Ro ad into t he circuit through adjustment of the l OOK input potentiometer. Then compen- Lansing, NY 14882 sate for the overall level by readjustment of you r exciter's own mike level control. T he Central Upstate New York's o utboard circuitry ends up wit h passive Mail·Order Headquarters diode com p ression. T he number of dB's of co mp ressio n will vary here if you ex peri- Specializing in Two-Meter FM ment wit h vario us types o f diodes. Since the and Quality Used Gear time consta nt is controlled by the 50 IlF capacitor and the 5K resistor, some ex peri-O f fice a nd Salesroo m Hours by Appointment O n ly me ntation here too will provide some differ- ent and measurable results in the output. 24-Hour Phone: 607·533·4297 Regardless of what the output meter Send SASE\" for Bi-M on thly Listing of: says, the acid test is how it sou nds. Distorted compression is worse than no comp ression at Used Eq uipmen t and Bargain Goodies all! Here's whe re your frie ndly tape record er is better t han your friend ly \"friend's\" ears. T r ade- i ns accepted o n bot h new a n d used If you hanker fo r some of t hat o ld D· I04 eq u ipment. Cash deals get prepa id shipp ing in pe netrati ng quality with high talk-power pu nch for mowing down the DX, you can t he Continental USA plus a 15 % discount on get it. Depending on your mike and your voice , experiment with input coupling capa- t he items o n our regular listing!l1!! citors ranging from .0 0 1 to .1 IlF. Run a test through a tape recorder . .. you'll knowCLEARANCE SALE when it's right. The .0 I is just right for my voice; it may not be for yours .Send for FREE list of select usedequipment at a spec ial discount This ty pe of circuit will perform withof 40% off regular prices. Savings almost any kind of an audio transistor at voltages ra nging fro m two penlight cells to agalore!! T.T. Freck, W4WL sta ndard 9V transistor battery. Germanium diodes are p referred to silicon diodes due to FRECK RADIO & SUPPL Y CO. operating ref'erence levels . 40 Bi ltmo re Avenue One final word of caution. Always shield P.O. Box 7287 such a circuit well in a suitable minibox. An rf choke and small bypass filter is desirab leAsheville, North Carol in a, 28807 in the hot input mike lead. If you run aTelephone: 704·254·9551 linear kee p an eye o n a scope fo r \"fuzzing\" of t he pa ttern as an indicato r of rf leak ageFM Schematic Digest into the unit. Circui ts like t his lend them- selves idea lly to perfboard lay ou t and con- A CO L L ECT IO N O F struct io n. MOTOROLA SCHEMATICS If you possibly can, play with matchingAlignment, Crystal , and Techni cal Notes the critical components to your custom tailored requirements, utilizing the tape re- covering 1947·1960 corder as the judge . Then put it on the 136 pages 11 Y,' x 17\" ppd S6.50 air .. . and better yet . . . don't use a linear. That will prove to you (if you have done S. Wolf your homew ork right) tha t you rea lly have Box 535 gotten so met hing - almost - for no t hing ! lexington, MA 02173 WORLD OSLBUREAU5200 P.Nma Ave., Richmond CA USA 94804THE ONLY aSL BUREAU to hendle ell ofyour QSLs t o .nywh\". ; next door, the \" • • tstete the next county . the whole world. Justbund'ie t h e m up (p lease arr ange alphabet ically)sc:and send t hem to us with p ayment of each. . . .W6JDD7!1' 73 MAGAZ INE

Gerald &y WIGQG 47 Rockspring Rd. Stamford CT 06906AN INTEGRATED , CIRCUIT S L RECEIVERM any hams received their introducti on The receiver described in the following to radio t h rough listening t o the sectio ns met these objectives and has pro-international short wave listen ing (S WL) vided many hours of pleasant listening tobands. T he t hrill of sitting in your own stations in fo reign lands.home listening to a broadcast by a sta tion ina foreign land was only exceeded by the The Integrated Circuitrealiza tion that one could become a ham andconduct an international two-way conversa- Upon review of the numerous analog oftion. ICs available, the Amperex TAD-IOO was selec ted. This device provides all the active The trends to SSB and all ham band components needed for a complete AMtransceivers increased the effec tiveness and broadcast receiver exce pt for the comple-pleasure of hamming. However , the capa- mentary pair audio o utput transistors. Thebility to browse the intern ational broadcast internal oscillator is only o perable to aboutbands is often missed. Building a simpleconverter ahea d of a SS B receiver is no t 3 MHz but the mixer gives go od results to 27sufficient since the bro adcast stations use MH z when driven by an exte rnal o scillator.AM. T he circ ui t of th e TAD-IOO is sho wn in In addition to the construction of a Fig. 1. Q I an d Q 2 comp rise a long-tailed-pairreceiver converting the SWL bands, I wanted mi xer and Q3 is a d c cou pled oscillator. Into build a receiver using integrated circuits the SWL receiver, Q3 is prevented fromto the maximum exte n t possible. Design oscillating and the external oscillato r injec-objectives included: covera ge of the 9, 11 , tion is applied t o th e emitters of Q I and Q2.and 15 MHz bands plus WWV at 10 and 15 An ex te rnal ceramic filter provides selec-MHz; Sufficient selectivity to adequately tivity be tween the mixer and i-f amplifier.separa te sign als o n the o ften crowded bands ;good sensitivity without the use of an A three stage i-f, consisting of Q4, Q5,ex ternal antenna; reasonable fidelity and and Q6 provides amplification. A de feed-stability : and simplicity and low cos t. back circuit (pins 10 and I I are de connec- ted ) aids st ability. Q7 is the AM detector and Q8 a nd Q9 fo rm a long-tailed-p air audio preamp lifier section. A Darlington circuit , Q10 an d QII , drive a 2N4107 complernen-FEBRUARY 1974 71

MIXER OSCI LLATOR IF AMPLIFIER DE TECTOR o AUDlO ~E -AMP AUD IO DR IVER STAGECD \"0 e CRO CR' 4 .7K 0 @@ $CR' 0' 1.8K 0' 0 10 ~ @ \ ) I~ 07 080' 0' '\" IO~ ~~ b ~ d QI~i7' -' 0 7 '\"0 \" (\"0 680 • 6.8' 0 0' 70 ~ 2.7K o Fig. 1. Internal circuitry of the TAD-100.ta ry pair to 0.7 watt au dio outp ut with a 6 A ferrite rod an te nna gives the receivervolt su pply. some degree of portability. This also allows an increased Q of th e coil to improve Ex te rn al circuitry provides 20 dB nega- sele ctivity. The ferrite rod was scroungedtive fe edback fro m the external audi o out- from a transistor radio so its characterist icsput stage to the audio preamp to ensure are unknown. Some experimentation withconsistent performance and to reduce the the number of turns may be required toeffec t of supply voltage fluctuations. The achieve proper coverage with different rods.age voltage derived from the emitter of the If the receiver is used near a transmitter,detecto r co ntrols th e gain of the mixer back-to-hack diodes should be connectedthro ugh an exte rn al d ecoupling network and across Ll to prevent damage to the IC.gives approximately 60 dB of age range . The receiver tunes from 9.3 to 18 MHz. The cerami c i-f fil ter has a 3 dB band- The elimination of bandswitching reduceswidth of 5 kHz and is 33 dB d own at +9 circuit complexity. An imported dial fromkHz. Ultimate attenuation is 90 dB. Audio Allied Radio Shack serves as the main tuningdistortion is under 2% at 0.6 watts output. dial. Bandspread is a little marginal using thisSen sitivity for a 10 dB signal-to-noise ratio is approa ch but it takes only a few minutes tojust under I j1V into 50n at I MHz . This develop the necessary skill.figure will degrade so mewhat at the frequen- C 1 is a surplus variable which has 3cies covered by th e SWL receiver. The sensi- sections of 50 pF per section. Only twotivity is quite adequate and signals from all sections were used. Similar capacitors can beover the world are easily received that are substitu ted. CI A tunes the antenna circuitwell ab ove th e no ise even though an external while CI B tunes the high frequency oscilla-antenna is not used. tor. C2 is a trimmer which achieves tracking between the antenna circuit and the oscilla-Circuit tor. Figure 2 shows the circuit of th e SWL The oscillator uses an RCA 40240 tr ansis-receiver. Where possible , junk box or surplus tor. T his inexpensive unit has a high betaparts were used to hold down cost. The and a high jt. Numerous oscillators havevalu es shown for the components in the been construc te d with this device and itaud io and age circuits are the recommended always performs flawl essly. To cover thevalu es from Arn perex's Report No. S-144. In wide frequency range, a Hartley circuit wasmy receiver , su bstit u te values were often designed. The tuning capacitor comprisesused which close ly ap pro ximated re com- almost the entire tuned circuit capacitancemended values.72 73 MAGAZINE

The F.M. Transceiver •Here it is. the FMer's dream. a fully synthesized transceiver that'll cover the entire twometer band, PLUS a built-in scanning receiver that'll locate any repeater frequency inyour area that's in use.And get a load of these other features that make the ultimate rig:• Operates on FM, AM or Modulated CW• Built-in DC and AC power supplies• Frequency Range of 143.5 to 148.5 MHz in 5 KHz increments• Autoscan in 5 KHz steps across entire band, with adjustable speed and frequency limits.• Synthesizer flexibility that offers choice of 600 KHz up or down, 1 Meg up or down, simplex,frequency split, or any nonstandard split (programmable) all from a single function switch.• Receiver Sensitivity of 0.35 My for 12 db SINAD on FM• Dual power output of 20 watts or 5 watts across entire band• Adjacent channel rejection 130 KHzl 100 db minimum• Image spurious and intermodulation lElA) 80 db minimum• 10 pole, 13 KHz crystal filter• Receiver Superhet, single conversion• Frequency stability of 0,0005%• Built-in tone burst and PL encoders and decoders• Built-in touch tone pad• Full LED Digital readout• Built-in S Meter also serves as VSWR bridge, power output meter, battery indicator, deviationindicator and discriminator meter.• Audio output 4 watts @ 10\"10 THO• Speaker built-in to left side of cabinet for maximum mobile reception• Headphone jack for noise-free mobile operation• Independent selectable priority channel $995.00• Built-in Auto CO $100 deposit will insure• Temperature range from _200 to 170° Fahrenheit ea rly delive ry an d guarant ee• Size: 4\" H x 8\" W x 10\" 0 Weight: 10 pounds pnce• One million channels (1000 Rec. x 1000 Trans.IYou owe it to yourself to go first class. Try an EBC 144 - You deserve it ! ncy n15V River Street (914) 235-9400New Rochelle. NY 10801 AMA TEUR PRODUCTS DIVISION

and thus permits the coverage of the wide Parts Listfrequency range. The oscillator operates at C1A ,e Dual-section variable capacitor, 50 pF per455 k Hz higher than the desired signal. This section.places its harmonics within the range of an C2 1.5-7 pF trimmer.aU ham-band receiver at critical points toassist in receiver calibration. FL 1 Ceramic filter, Amperex part No. 8222410 42010. A curious problem developed in the L 1 11 turns no. 16 spaced over 2%\" of a 5\" xinitial receiver design. L2 approaches self-resonance in the commercial FM band . 1/4\" ferrite rod.Harmonics from the oscillator were strong L2 1 tum link wound over the cold end of L 1.enough to produce FM signals aU over the L3, L5 19 turns no. 24 close wound on %\"dial. A simple low pass filter , consisting of diameter form (use an old resistor 1 megohn orL3, L4, L5, L7 and C8, eliminates the larger!.problem except for a few weak spurious L4 Ohmite 2·144.signals outside the SWL bands. My location L6 27 turns no. 24 wound on 3/8\" diameteris within a few miles of some very high slug-tuned form.power commercial FM stations. If yourlocation is less severe, the filter may not be L 7 4 turns no . 24 wound over the cold end of L6.needed . La 1 turn no. 24 wound over L7. The signal input is applied to the base ofQ I and is mixed with the oscillator signal 012, 13 2N4107 (consists of one each 2N4105applied to the emitters of Q I and Q2. The455 kHz i-f signal is taken from the collector and 2N41061.of Q I and passed through the ceramic filter,FLI. C26 must be a high quality bypass and 014 40240.should be connected directly between pin IIand pin 7 of the T AD-lOa using short leads. 015 Any NPN transistor in TO ·5 can.Some i-f instability was present using therrianufacturer's recommended circuit. This Sl On-off switch on R6.was cured by using an additional bypass,C 17, connected between pins 11 and 7 of T1 117 V .A .C . to 6.3 V.A.C . transformer, Olsonthe i-f filter using short leads. T·76. After i-f amplification and detection byQ4, Q5 , Q6, and Q7, the audio and age U1 Amperex TAD·l()O integrated circuit .voltage are present at pin 8. R I, R2, and C4comprise a decoupling network with the Also, the quiescent operating point of theseproper age time constant. The age voltage is transistors did not appear to be critical so afed back to the mixer through L2. Bypass fixed resistor was substituted.capacitor C13 is connected to the dc linerather than grounded to avoid i-f feedback . The power supply circuit is standard withR5 and C 18 form a decoupling network to the exception of the filtered supply to theprevent the 455 kHz i-f signal from entering oscillator. The audio stages draw fairly heavythe audio stages. peak current causing the base-emitter im- pedance of Q 15 to vary. This leads to The audio stages are fairly straight for- enough change in output voltage to causeward. The RC networks are designed to the oscillator frequency to vary if it isprovide proper bias for the stages, to provide connected to the same line. Thus, voltage fornegative feedback for improved stability, the oscillator is taken from the zener diode,and to limit the frequency response to about D5, which is much steadier. QI5 is an 12 kHz. Amperex recommends the use of a unmarked NPN junk box transistor. Thepotentiometer in parallel with a thermistor requirements are not critical and nearlyfor R 13. The author found no heating of anything in a TO-5 can will suffice. If Q 15QI2 and QI3 under normal operating con- does not overheat when testing the receiver,ditions so the thermistor was eliminated. it is probably good enough. Construction A homemade \" L\" shaped chassis and panel was formed from an aluminum cookie sheet. A surplus walnut cabinet from a small stereo receiver housed the unit. The tuning variable, CI, is mounted in the center of the chassis. The TAD-lOa and its associated parts are mounted on one side of CI, and the oscillator and power supply are on the other side. The ferrite rod antenna runs parallel to the front panel on the rear lip of the chassis.74 73 MAGAZINE

Oil 60 05 06 ~2C0204}IF SPEAKER 6:4 V ' 90 5 K ./ 3.2.{\. CI2 l U;\" (;7CI3 <, 6.4:J;0 1 200J~\" \" : '7 00 10 K 8.2 I( JI ~~ =- t;1~;J;C4 ~ 07 0 12 0 12 ± C25 • IK ' 902IO5V)lF 2N4 10!5 320 J,lF 02 _ 0I1 fC , ? ± 0 13 6.4Y 47 ~ 8 .2 1< 0 013~I~I U:CI' I ..... R9 2N410600 >L- 2 4 7: 10K i7\ UI 1frrr r7/1 ~~ I, 0 14 TAO-IOO •II ; ~~12 3 .9t< 10 015 - 14 C26 4 .7 K 12 .47 rh 04:+C!5 ,... 3 14 10 ~3l2J1l-/4 V ~1 OlD C6;:!::: R4 FL I 27 .0 05 rr-r- 7I _L. ,If ;;;.1O\",C17 I, >-L >- ' C7+ >>--L' 4 47,J; ~~;t >- 014 crJ~ >-L. 40240 CI O 0 016 .0 4 7 r-. 22K L6 L >- 1C),\".FM ~ 01 7 015 0, ~ 50 .... >-L7 LB- >- I '9K ./BOTTOM VIEWS , FLO rL I00 0 Ria _ ~ C914 7 \"10 10~7 JOOO~ 0 Sl I 11 0 1-4 't' HEP I 7 !5 TAD- IOO 0' 331 234567 C14 ~ +~ + Cl~ -. r± ,J141312/110 9 3 00 J,lF CIO < i\" ~O IIF D. 300\" HEPIO 10V IOV V I Fig. 2. Circuit diagram of th e SWL receiver incorporating the TAD-100 Ie chip. 75FEBRU AR Y 19 74

Layout is not particularly critical but hookup wire antenna from the ham receivergood rf practice should be followed. Be sure to a point near the SWL receiver. With thenot to enclose the unit in a metal box or plates of Cl fully meshed, tune the slug insignals will be prevented from reaching the L6, L7, L8 until the third harmonic of theferrite rod antenna . oscillator is received by the ham receiver. The Amperex application note suggestsmounting the components on a printed This corresponds to an incoming frequencycircuit board and the use of small transistor selling of the SWI. receiver of 9.3 MHz. Ifradio parts. In the interest of simplicity, no signal can be heard, check the polarity ofdirect wiring was used with components the windings on the oscillator coil. 1.6 andphysically larger than the recommended 1.7 must be phased properly or the circuitparts . No unusual troubles were experienced. will not oscillate.The T AD-lOa is turned on its back with its\"legs\" in the air. Connections are made Next, place your fingers on LI to de-Qdirectly between the pins (use a minimum the circuit. As you tune up the dial, the 9 MHz shortwave band should be present overamount of soldering iron heat and applica- the first 20% of the dial and WWV should be heard at 10 MHz.tion time) and several nearby terminal strips. All ground connections should be made While listening to WWV at 10 MHz, adjust the spacing of LI, by compressing or spread-as directly as possible to pin 7. This is ing turns, until the signal strength is maxi-especially important for C26. CI3 should be mized. Continue tuning up the dial until, ata small size ce ramic capacitor and is about the midpoint , the II MHz shortwavemounted as close as possible to pins 8 and 9 band is received. Picking a strong, steadyof the TAD-lOa. signal, adjust C2 for a peak in signal strength. This is only a temporary adjust- The ferrite rod is mounted several -inches ment of C2 to get it into the proper range.from other components to avoid feedbackproblems. In my receiver, a short piece of Next tune further up the dial to the 15shielded cable connects 1.2 and the IC MHz shortwave band. Finally, peak C2 on acircuitry. A small vertical shield is mounted strong signal. The trimmers in FLI can nowbetween the ferrite rod antenna and the be adjusted for the best sounding signaloscillator circuitry to prevent oscillator har- quality. After rechecking these adjustments,monics from reaching the antenna circuit. the receiver is properly tuned. The dial can be calibrated using combinations of oscilla- The oscillator and harmonic filter com- tor harmonics as received on the ham bandponents should be securely mounted. The receiver, WWV signals, and received short-requirements are not too critical, however, wave signals.sin ce the received signals are AM. Severalhundred cycles of drift will not cause any Conclusionsnoticeable change in the received signal. The receiver performs remarkably wellTesting and Calibration considering its simplici ty . Sensitivity is more than adequate to fill the dial with signals and All semiconductor devices are unforgiving the ceramic i-f filter ensures good selectivity.of wiring errors and it is always a good Not surprisingly, the lack of image rejectionpractice to recheck your WIring job against on the higher frequencies is noticeable. Athe schematic . Also inspect carefully for very weak image on the 15 MHz WWV signalso lder bridges between pins on the IC and can be received for instance. Within the SWLshorts between components. Apply power bands, however. few problems exist.and check for approximately 6 volts at theemiller of Q 15. Some noise should be heard The TAD-lOa is a remarkable device andfrom the speaker. certainly should have broader applications. For example , by using the internal oscillator Calibration can best be accomplished at and tuning the input frequency to 1.5 -2night when plentiful signals are present on MHz, an excellent back end for a portablethe bands. The oscillator calibration is the two meter AM set could be constructed.first task to be accomplished. Tune a hamband receiver to 29 .265 MHz and place a . ..W1GQG76 73 MAGAZINE

FINAL ASSEMBLY Bill Hoisington KICLLAND FIRST Far Over FarmNIGHT ON Peterborough NH 03158THE AIR •[with the 432'er) \'/ ••A t last into the home-stretch with o nly a Figure I shows the d etails which by now fe w trials and tribulations ahead. You wit h t he use of lumped circuits constit u tewo uldn't ex pect a complete station to go p rac tical ly a sta ndard schematic fo r 4 32together just like that would yo u? It almost MH z. At least th ey all work well,did , Nothing really se rious, b u t it might hityou too, so here are the details. Now we. have a t riple r crystal exciter and three rf stages, but we also have increased My only 54 Mll z rock , left o ver from drive and more o u t pu t.dry-cell battery tube work o f ten y ears ago , Another knotty one , Or rather t wo to-has always had a big \"w\" in ked o n it. This is get her. When runnin g high gain lo w freq uen- cy selective circuits, nuisan ce feedback ismy sy mbol fo r weak, and it was, Worse th an easy to come by . T his is o ne you may wellthat it d evelo ped a particula rly viru len t form encou n ter, so we'll wa rn you no w, andof nastiness, You co uld n't exactly call it furnish th e remedy also . The 135 i-f stri pintermittent , it just fad ed awa y or would n't and uf were running fin e, but as soon as thecome on at all . 1.6 5 MH z i-f was plugged in , zilch ... S meter dr op ped near ze ro, and t he d arnd est I plugged in a good 53 MHz crystal and lo w af rumble and wa rble you ever heardthe out put power ju mped as did th e exciter came out of t he speaker wit h a hashed-u pmils as th e multiplier stages go t plenty of signal also. With separate batteries - fi ne -drive. This was fine, but of course th e last but that's no sol ution . Inclusion of a lOond oubler was now on 4 24 instead of o n 4 3 2 resistor in th e plus batt ery lead to the B plus bus in th e st rip did the j ob, excep t fo r th e There re mained the tripler exciter, wh ich second part of the trouble which was thesho wed an insufficient amou n t of driver, as resistance o f t he o uter cond uctor of somementioned before . The obvious answer was old thin braided micro phone cable beinganother rf stage, a \" pre-dri ver \" as it is called used to connect the two i-f strips. The outerin solid-sta te circles. There are fo u r rf stages conducto r ac tually measu red I/lOthn, soin th e shack now, so o ne was t ried out and beware o f that stuff. Eve n a good piece ofworked even better t ha n the d o ubler exciter new RG-58 ca ble when used with co nnec to rsalone, like over 150 m W ou tp ut on the fina l. whi ch were not ab solutely new and shinyAll fo u r of these little planks are in usehowever, so I had to throw another o netogether for this pre-driver stage.FEBRUARY 1974 77

PRE - DRIVER Fir = __,--c II FOOT STAGE , 4 32 ER cAaRe a COPPER12 VOLTS SlOE '\" co cII( 33POT OI-lMNOTES ' C2 Cl o JOHNSOt<l ~PLATE 16 0 -102 . ARea ct.C4 THRU DIPPED \"'leA, 150pF, \"\"eas Uo :5 t URNS COPPER NO. 16, 2N360 0 _(C}em 1/4\"0 0, li Z\" LONG . , J2 TAP 1 TURN, COLL ECTOR AT 2: TURNS . Fig. 1. Pre-driver rf stage, 432'er.caused trouble. I mean the connectors, of noise figures were obtained with these, ascourse. A good short ground between the well as less confusion in circuitry and bat-two strips did the job right. When you want tery polarity. A negative ground can now besmooth, trouble-tree operation of high gain used throughout, and you can forget aboutstages, you must take certain precautions. PNP transistors except possibly for high power modulators later on. There is something fascinating about agood double-frequency i-f that handles well, No change in the coil windings wasis free of feedback, has good ave, and needed, other than to lift the co llectordoesn't cost too much, so your buddy can return from ground and bring it to the plusduplicate it and take it with him to another 12 volt bus. Figure 2 gives the final i-f circuitmountain 100 miles away . That is, it's which works like a charm.fascinating once you get the bugs out of it. DC Levels Sorry, OM, but there's another i-f toconnect to that same battery. and yes, I When changing transistors in an i-f stripknow, don't tell me, the same thing occurred or of course when making up a new one, it isagain. Low frequency burble and rumble, very important to set up the de levels on the emitter and base of each device including thewhen the ten meter receiver-tunable i-f was diodes. I say diodes because once having tried separate diodes for af and ave I'll neverplugged into the 1.65 MHz i-f strip, and also go back to a single one again.into that one battery. This time the remedywas soon applied with another lOOn resistor Referring to Fig. 2, the base de level ofdoing its stuff in the B plus load. There was QI is set by R2 and R8. These are nota 100 /IF capacitor to ground already in the critical but must be set properly. A balancestrip from that bus. between R2 and R8 is important for proper avc action. If R2 is too small too mu chImproving the I-F Stages current will go through Q I. If R8 is too large too much ave voltage will be lost in it. The The i-f stages were originally built with values shown work fine with 2N918's. A onesome five year-old PNP devices I had around, millimeter in the emitter lead of Q I shouldand in the interests of battery compatibility, drop from 6 or 8 mils to less than 100 /IAit was thought best to change over to NPNjobs. Improvements in burn-out and better78 73 MAGAZINE

I ~ -!t I\" :;,l- '\"0' ; ~v \"'0' -b,o .\" \"1 ?) r • ;~ o ~T= \" '\"0' ' :oc; - 0'1\ ~ 2'<':118 ~ 'E-- °'U,\" O~ II 0'~ 2 '<91 8 \"z21< ~~ :o~ \"'00 D2 o T J2xI ) c~ r-,--J/\0 \"\" )~'0i~ ~~ --,! -- ~ ~O\" Ave LI NE \"SEE NOTES ± ::; :0 \" \" -~_6 1< -::: \" \" • 6•:J - \"s\" METER Fig. 2. 13 5 kHz i-f strip reworke d for NPN transistors.wit h almost any kind of a good signal at J I . The choice o f i-f bandwidth can be very useful at time s. The narrow band i-f requiresI use a little h omebrewed atte nuato r bo x as careful tuning and can be subject to certainin Fig. 3 with the La fayette signal generat or crysta l and o ther oscilla tor drifts, not onlyon 13 5 kH z fo r those low signal level tests. in yo ur rig but the other lad's as well, andDo no t expect to be able to d o this o n the also with temperature changes and possiblehigher freq uencies tho ugh . Those kind of voltage d ro ps. It is smoot h and steady whenshielded generators are in the $300 to $400 use d on the air, as you will see later, b utrange instead of the $30 to $40 one . whe n it comes to making all sorts of antenna and r f stage tests the re's nothing like a little The two emitter pots in Fig. 2 are bandwidth. By \" little\" I mean a \"good littlepractically standard items, SOOn or I K , with amount of it. \" The 1.65 MHz st rip provideslimited resistors of 33 -0 100n, depe nding o n j ust that with about I 00 kHz bandwidth. Alljust what devices you are using to kee p you have to do with the rig (as now putmaximum current below 10 mils (in most together) is change over th e af plug from thereceivers under test here ). Final good , narrow ba nd to the broad band strip, etsmooth-working va lues are given in Fig. 2, voila, instant ease of adjustme nt. Thereusin g the 2N9 18's I have at t he mo men t in happe ns to be an \"S\" me te r in this st rip also,th e 135 Hz i-f strip. These are higher so all kinds of relative measurements can befrequency devices than needed . 2N9 16's made on antennas, cables, rf, etc . The sharpwould be just as good . i-f rul es th e roo st th ough with the band load ed (on 4 32 that 's more than o ne other Once y ou get t hem adj usted to whe re you station l). And of co u rse when th e bandwant the m, you can of course go to o nly o ne o pens it is an absolute must.pot for th e i-f gain co ntrol. Installing the Two Low Noise Stages in theChoice of Bandwidth and Gain Handling of Rack.th e two I-F Strips Just fo r security against feedback these This has worked out fine . Each o f these were mounted on a single copper-cla d base-strips originally had a pot in each emi tter ofeach stage and o ne for both stages togeth er. 100 TO ONE AT TE NUATORIn use on the air I find that the last t wo FOR I F TESTSstages which make up the narrow band h ighselectivity strip o n 135 k Hz ca n be left alone BUO MIN BOXat a fixed gain, and the over-all gain can beset by the pot which co n trols both the Fig. 3. 100:1 attenuator for i-f tests.emitte rs of the 1. 6 5 MHz st rip . This o ne alsoserves to set for maximum the gain of thatstrip wh en it is used alone . So much fo r i-fga m .FEBRUAR Y 1974 79

I + 5 8 / U CABLE cr \" C2 I • \"CO A RCO '\" 833ANTE NNA _ _ , (/) I C3 2- 30 FCAB LE IN (/) T I • , C I , - / L1 _ _ TO MIXER -I ISMALL IB R ASS SHIELD 2: 1/4\" HIGH 3- I.OIIIG I.~ TO 5pF 1.5 TO 5pF - J O ~N SO N J OHNSON ~ T YPE III TYPE M COPPER - CLAD BASEBOAR D 9 112\" WIDE BY 6 112 - OE EPNOTE S :Ll o 2: TURN S NO.••.LZ. 2: T URNS INSUL AT ED INT ERL EAVED IN L l.C4 ' J OHNSON TYPE U !5 PLATES ( ABOUT I TO !5 pFI.FDA AL L OTHER OETAILS SE E LOW NOISE S ECTIO N, Fig. 4. Final layout, low-noise rt stages, receiver, 4 32 'er.board on th e top shelf an d given the filter receiver pass band . After mounting every-treatment in each plus 12 volt lead . A small thing o n th e carr ying rack shelves, b eginningshield near the coil job removed a slight at th e bott om, with t he af and battery, th entrace of rf feedback under certain tuning the 135 kH z st rip ; next th e 1.65 MH z j ob;conditions. The layout is sh own in Fig. 4 , tunabl e i-f mix er, an d local oscillator on thewith the main points for tuneup and adjust- third sh elf, and the two low noise rf st ripsment being C I, C2 , C3 and C4. No bugs on top . Bonding was installed piece by piece,showed up here. The manufacturer of these checking 0 11 that weak signal all the time, aslow noise devices, KMC Semi-Conductor, well as for tuning and handling. For thisInc ., Long Valley, N.J ., sta tes that for the type o f bonding I use No. 12 solid co pperb est noise figure use only a few mils, like 2 wire in pieces only 2 - 4 in. long between th eor 3 . This was found to be true , although the cop pe r-clad baseboards on the shelves. Whilegain goes up when 10 mils are used. Remem- some o f this bonding cut down the signalber though, gain we've already got , low-noise sligh tly due to elimina t ion of nuisance rfis that illusive thing we're after. On this feedback , the ent ire job brought the signal up and eli minated rem aining traces o f feed-subject, the I mW test signal on just a dipole back and hand capacity .was st ill com in g in five miles away. It is har d to draw the li ne be twee n a collec tio n o f mi niboxes an d 100 lbs of iro nBonding ( I mean co ppe r o r alumi nu m) cla d co nst rue- \"tion co st ing yo u-know-how-much . Wha t I'm This may sou nd like a low frequen cything, but it goes for both high and low and afte r, and I think most readers wou ld likein between. On the low frequencies you canget that nasty af rumble with the S meter also, is to fina lly h ave a good battery-oper-going toward zero witho ut any sign al ; on hf a te d , lo w-cost receiver that you hea r DXyou ca n get hand capacity when tuning with with on 432 that h and les well, no t tooa narrow band i-f; and o n UHF you can get touchy o r j u m py , an d still h as roo m fo rmo st a nyt h ing. Like oscillation s in an rf im proveme n t and growth . Sound s li ke astage, rf tuning reaction o nto the crystal- pre tty big o rder, and it h as been ac tuallycon trolled lo cal oscillator. (Ye p !) Don't for- tha t because - inclu d ing the t ra nsmitte r - itget the frequ en cy multiplication for the 48 has tak en ove r three month s to build all theMHz rock up to 432 is nine times, and a units, work out th e bugs, dra w up themere 300 cy cles can throw you o u t o f the circ u its an d layou ts, an d get every th ing80 73 MAGAZINE

SOLDER BRAIO RECEIVERS, OK GRTO, WITH BOOKS: :\0 OHM CABLE FROM A~TE ~ 'OA sp·600-JX: AM, cw o0.54-54 MHZ coo tlnuo~ 275,00 ; \",- INNER CONDUCTOR P38B/ URA , AM, CWo '1, ,301', MHZ linear d ial, PTO 325,00 T- ' ONE OF THE ANTENNA R390A/UR R: 'I.. 32 MHi bv d;g its, PTO tun ing .. , , ,. 595. 00 CHANGE OVER CONTACTSCOPP ER CL A_ ,D/ ANfFRR ·59B Itater vp r ~;on of WAR 2 l: 2-32 MH l d>g ital tune each 500 Hi~ 112 · BY 3\" CERAMIC BODY o r con unuocs. A t 2.3. 9, F l . 4, FAX FSTT Y. SSB. carfl~r suppres~ ellh er band Of bo lh tor 2 d, ff\",rent ;nl\",Ulgences . Stable and aCCurale OF SWITCH enough 10 use as tr eq , \"\"\"Ier' Ner WI. 276 IIls _m 2 cabme rs ,n 'ack cradle _ 1/ 16 \" SPACING 750.00 WWVB 60 KHz rI!CV' compara lOf ., ...... . . . . . . . . . • . • •. .. 295.00 WWVB 1 k Hi tOlll'Sjl l 1 5f\"Cond Inlervals 175.00NOTE : 38-1000 MHi by Band Swilching. 4 bands Separat.. en....na lor eecn KEEP IN'OER CONDUCTOR WIRES TO band .AN /A LR 5 mod;!ied for 117 v 50'60 cy II'll\". AMIF M. The Tunt' r IS CONTACTS Ell:TRE MELY SHORT . a p lug-;n conve.ler: the recei~.., rs 30 MHi IF and all tha t fo llows IF. Choose selec tivllll'S 200 KHi or 2 MHz eoch side of cenll''' FacloryFig. SA. TR switch, 432'er solid s tate. chec kou l sheet , tv pic al for th e Ori9lnal-p;u;:k Ill\"\",r you qe t . say~ sensitivitv ra nges Iro m I,I I' V at 213 MHl 10 7 al 1 gHi. IF auenua ror i~ ceubr etee in 6 dB step s to - 74 dB. D,od!' currenl meter makes th;s revr useful fOf . ela tlve he ld slrength measuremen ts and harmonic find e•. Rev. un;1 is e~c. used and chec ked OUI O K . . . . • . . . .•••••. • . . .. .. \" .. . 375.00 30 MHz PANAQAPT ER ma v beuSl'ful wllh above . . . . . . . • . 295.00 A.I .l . 13 230 MHl r(:vr!ampli f,er /atten. canb. . . . . ... . . . . . . • . 99.50ru nning smoo thly. That thre e months, I EDDYSTONE AM /CWfFM fNBFM 19-165 MH i rev. . 295.00might men tion ,i s o n a six-and-a-h alf days perwee k basis. And it won't tak e you that long CV-59 1A : SSB Conve rler I'lthe r 5ide band 137.50because we've worked almost everything out MOTORO LA 3 MHz OSCIL. 5 par ts in 1010 11 th , , 19 9.50for you . and you can start from there. ATTENTlON 'The T-R Switch Buyers. Engineen . Ad vanced T&d>noc ians: There is an easy way to handle this in a We h _ the best tf!1it-eqll\",ment & 05C,1I0S1:0I\"\" ,\"\"\"\",tory '\" the cou ntry $0bat tery-powered rig; just use a rotary ce r-amic switch, reworked a little fo r UHF. ,,$1< for vour neerlJ . .. don't ,,$I< for \"n owr\"fI c\" .\"log _ \"'50 bvv. 50Pro o f of the pudding is on the air. tell u, what VOU h_. PrICe I t. The main deal is to keep the co n tacts asclose as possible to a flat grou nd -pla ne NEW FOR 74backing for the sw itch, as in Figs. SA and B. ECM 5A FM Modulation MeterI have tes te d this out on 4 3 2 MH z, and th ere • O,,\".ln 3D-SOD Mhl Only SISOO ':~':.~~:is no noticeable loss involved in go ingthrough the switch , Use o ne set of con tacts, • Cry.llIl tonl' Dtled ID' 1.1 and n ,yas in Fig. SB, for t he anten na changeove r Dpe•• I,onsection; the rest can be use d \"as is\" for d cco nnect io ns to tum on t he transmitter, turn • Pe.k lea di ngo ff th e receiver, e tc. , with no special precau- • B,Il.,v pow. ,ed w\"h AA pe\"\".111tion needed in their wirin g. Phone or write \"S k'I1'\" W9HAK ----..-_ •--- • The switch is mounted on the transmi t- fOf cOrTln1el'\" mforma tlon D,alter, although it could be put o n t he receiverrack just as well. 8 12·476-2 121 With medium size beams and (see later) ECM Corpor al lonan te nna mounts fo r use o n th e sides of both 4 11 N _We'nbach Ave .th e transmitting and receiving racks, along Evansville, Ind Iana 4 77 11wit h t he T- R switc h, co nsiderable flexibility•of operation is obtained . Either the transmit- DRAKE . REGEN CY . HALLICAAFTERSter or the receiver can be use d separa telywit h t heir own portable beam in the car o r ANT . SPEC . • TEN TECshack, or with a really big beam for serio us GUSH - CRAFT . MOSLEV • HUSTLERmountain-topping. With th e latter the T-R isrigh t th ere ready to be used . new\"nd The tra nsmitter and receiver assem blies WA9CFU L EE (2 111 13 5- /265 usedhave phono jacks across their tu rn-onswitches which allow cables and plugs fro m WA90GD ROD 555 WOODLAWN ROAD LlNCOLN. IL 62656FEBRUARY 1974 81

vuhhff CONVERTERS FROM A\"'TE\"''''A T O TRAN$\"IITTER COPPER CL ADSTAR T CERAM IC $ WI TCH BOOYHE ARING the Fig. 58. Rear view, TR switch ,WEAK ONES . ... the T· R switc h t o turn th em on and off alo ng with the ant enna cha ngeover. I haven 'tVery senS;I;~e crysta l controlled corwe-ters for ,ece,vIrl9 the VHF bands with seen any lo w-cost battery-operated relays asvour present receiver 0' transceiver, ldeal lor OX, FM. Satelli te receouon or yet, but with the power avai lable fo r UHF solid state at prese nt this can be omitted.for iust talking to the gang, All have built in supplies fo r operat ion from The use of two racks in the car is not soeither 117 VAC 0,12 VDC, 10 Meter au tl' Ll! is standard. Be~,,',tuIlV. bui ll handy , but th e units will soo n be boiled down in size t o where they can go on oneafld carefully resred with modern e!.1u'pmm'lt . rack. First and foremost is the circuit and its50 CA, 50 - 52 MHI ••. 574 ,95144 CA, 144 - 148 MHI _ 51 4.95220 CA, 220 ~ 225 MH z . ... .• ......... 579,954 32 CA, 432 - 4 36 MHI $7 4 9 5JA N EL can also supply a 011,,\" Vd\"\"W 0 1 '«ewmg et1l11,,,,,..m fo, \"'duJI\"..1 co mpo nents. When you have these and they;lppltc;l fiofl 1. Wrll\" or cdll for d el<Jds work well , th en you can plan how to put them into little boxes. but not before.A ll ,tems are POStpaid ;lnd lJUiN,mreed Pfe<tSe order d\"ecl 0' W\"fe fOf OU'f' .... Ci\" afog ALSO - We nod< a lull hne 01 ile n~tlYe PR EAMP$'@ JB~ ~.~C~S~::A~~J::;;;es Car-top Antenna Mounts fo r the 432'er 'rete hone: 201 ·584·652 1 The first thing t o do is make a visit to Sears & R oebu ck for a $8.9 5 car-t o p carrier. They have one wit h wood cro ss bars whic h isWHY FIGHT CRM & CRN ? just fine for m obile beam mo un ts, as well asThe NEW DE·101 lamily o f $igoal ~.- :::.! for carrying big beams if you're the arnbi- 01,\", , ' tio us type . I generally positio n the twoDiscriminators is designed to fighl _ \" _ _01 tran sverse bars in the norm al fashio n on the car roof and then bolt on a 1 x 8 in. pla nkC RM and CRN fo' you without rig run ning fore and aft for the beam mountmo dificatio ns. Each d iscrim inator which is hand-rotated from t he driver's window. See Fig. 6 .un it consis ts of two 3 pole opera ......--T V MA$Tt ional amp. filters stagger t uned fo r ALU MINU M TUBINGa flal 100 hz b andpass at 1,000 hl , _ _ NOTCH F' OR . HOLDI NG ROTAT IONA buller amp. is included for earphones, or a 3 W pwr amp . for an 8 o hm spkr. No aCljus tmems, fac to rvtuned, p lug in installation , one yea, warranty, and 15 day returnp rivilege.DE 101 For earphones onlV. 115 VAC . $29.95 + S2 stllp .DE TOIA For Spk r& p hones, 115 VAC $39.95 + $2 snI pDE · lOIS For Spkr & phones 12 VDC . $29. 95 + $ 1 sn,p.DE· TOIC For e¥poones only. T2 VDC S19.95 + $ 1 snI p .CS I W' red & tested DE·IOIC CIi'C'Jlt bd, $ 14.95 ppd .CR·23 Walt A udio PWR A mp. fo , 8 ohm StJkf. 12 VDC /(/1 S8.95 ppd Wli'ed & fested $ 10.95 ppd.~ c•ee. 8 0J< 1131 (Heal\"'. A L 35601 • ••• WOOD ANGLE BRACKET F' ORE AND AF' T PL ANKI IQUADS! QUADS! QUADS! e' LONG 1\" WIDE BY I\" $56.35 up for q uad ki ts . $79.95 for ,(.:I~::'~\"~Ba E R MOONT$••• •••com plete quad s (p re-drilled a nd pre - ST RA P S -~ tun ed ). $ 2 69 .9 5 up for ou r new s upe r f WOOD BAR OF' .~~~ OR I Y E R $ CAR TOP CARRI ERI Iqu ad (p re-d ri lled and p re -tu ned. (Quads RA,'\" GUTT ER -•• WINDOWfor special purposes 7 to 150 MHz. ask LEF'T $IOE- - - OF CARI Ifo r esti ma te) E-Z WAY POWERS at Fig. 6A. Car-top antenna 'm oun t, 432'er. View from SPECIAL DISCOUNT PRICES rear of car. Ffee l iterature upon reque st , 1813) 988421 3 The use of a beam an tenna on a car is to me a very mtrigumg affair. You will find SKYLANE PRODUCTS ' OGA Bon A\" Ave.I • - • • • ITemp le T\" rf...ce. Fl 336 1782 73 MAGAZINE

ALUMINUM TU81NG beam o n a mountain-top lo cation , better U BOLTS carry along tnree small guy ropes for emerg- ency use, with a rotating collar. Those windsFORE ANO come up in minutes, and they blow. In manyArT PLANK places you don't need extra elevation , but sometimes you will find yourself in a park- Fig. 6B. V iew from righ t side of car. ing lo t just enough down off t he top of the hill to cause you troub le and will need thatthat most of the time on the main highways, extra 10 ft of h eigh t. Mt. Cadillac is o ne o fthe direction of the beam stays pretty well them, Do wn East in Maine .put, and only changes over reasonableperiods of time. For example , when coming Handy Beam Mounts and Fittingsinto a city from 30 to 40 miles out, youkeep the beam pointed mainly ahead for half As usual the TV boys help us amateursan hour, and - then while you're going out with mass-produced handy items such asthrough o r around town, the signal is lo ud the I I> in. OD aluminum masting for $1.25enough almost any where you poin t th e, per 5 ft or $2. 09 for lOft , plain . The $1 .25beam; as soon as you get ou t of town, you bit is for \"gold anodized \" whatever that mightpoint the beam astern and leave it that way mean . The new style plumbing lads also helpfor ano ther lengt h of time. The advantages with thei r black plastic PVC (polyvy nl-are great! The beam reduces flutter almost chloride) pipe which fits just nice and snugentirely with some 9/1 Oths of your power inside the aluminum roasting.going toward the other lad and not boundingaU over the scenery . There is 10 dB of gain Figure 7 sh o ws a handy rig for portablefor a good 4 elmeent o n two for examp le, work with the shelf racks, either transmitterand it can tell you where your friend's house or receiver o r both . The same antennas thatis if yo u want to dro p in fo r a visit and see plug into these mounts also plug into thewha t h e loo ks like ! car-to p mount, as you will see. I have started out from Boston at 5 pm I\" wooo DOWELL HANDL Eon two meters with a 4 element beam, goingto Washington, D.C., and wound up near the Fig. 7A. Wood rack antenna-mount, front view.Bay Bridge in Maryland at 2 am with steadyQSO's one after the other all the way . - « ;ALUMINUM Using a plug-in type of mast mount y ou STRAPcan run a 4 or 8 element beam on the carand change to a much bigger one when you RACKget to your favo rite hill-top. You can alsoplug in beams for other bands, o r even two • ,. •b ig \"wh eels\" stacked if you really want toexcite comments. Fig. 78. Side view. Figure 6 shows details of the car mount, Medium Size Beams for Portable and Caralmost all wood, and after the use of a can Use wi th the 432'erof aluminum sp ray paint (do this off the car)it looks fine . Two and three element designs (Figs. 8 and 9) are given to start you off po rtab le, You can use a good height above ground car, and in the sh ack. A high gain 14 elementlike th e big truck trailers, but watch out for job that you can install o n you r roof orplaces like t he Merrit t Parkway to ll booths. carry up the hills o n the car is shown in Fig.IO.They were not made for trucks. You have to Figure 8 shows the 2 element unit. This isstop o ut on the side and cart your dime overto the man o n foot. When you use this moun t 'with a largerFEB RUA RY 1974 83

- - - - - - - - - - - - - - - - - - - - - - - - - -1 tRI-t€k. me. 14 \" REF LECTOR P,O. BO X 14206 DEPT 7 RG- ~e/U CABLE PHOENIX , ARIZON .... 85063 ~ ~~:r· - tolASTVOLTAGE REGULA TORS MFC-6034 • • •VA RIABLE UP TO lOY. 200mA ..... 51. 00 a ooa III eec CEDAR M080S, 7R12, 7815, FIXED -VOLTAG E, lA • • • 52.50 MC7912 . 7915• • • • • • FixeD - VO LTAG E, lA • • . 52.50DTllNTEGRATED CIRCUITS 13\" flADlA~ ~ WOOOSCREW S930 . _•• DUAl 4 INPUT NAND GATE. . .•••••• • • S .30 21 /2\"C ENTER TO CENTER946 • •••0UAO 2 INPUT NAND GATE S .30962 ... . TR IPlE 3 IN PUT NAND GA1 E•• • . . . . . • • 5 . 30TTL, NEW •• HOUSE NUMBERED•• SN70400, SN7402, $N7410, SN7430 • ••• •• . . . . ••S . 25TRA NSISTO RS NOTES' 2N3905•• H1CH SPEED PNP . HO USE NUMBERED 5/5!. I . V S\"CLOTHSUNE ALUWlNUtol USED FOR ELEMEHTS. 2. SMALL SR\"SS STRAPS AHD 21 !>6 N\JTS AND 80LTS MJE 1093• • PNP DAR LI N GTO N , lOW, BOv •• • • . 52. 2S JAN2222A • • HIGH SPEED NPN SwnCH • • • • • • • • S .39 FASTEN COAX CABLE TO RADIATOR. MPF 120••• 0 UAl GATE MOS FET ••.. •••• • •..• S . 75 Fig. 8. 2-eJement porta ble beam 43 2 MHz r top view. MFE 2000 • • • VHf/U HF N CHA N N EL JfET • • • • • • S .75 MFE 2OO1•• • VHF!UHF N CHAN N R JFET •••••• S.80 handy for test use , h idden t ransmitter h un ts by your club. and what have you . It 's alsoCAPACITO RS good for making up multi-element nat shaped beams whic h carry nicely on t he car.G LA SS SEA L TANTALUMS• • • bV• ••• N EW Next comes the 3-eleme n t o ne, nat u rally, . 47u f, 12/S1 . oo ••• \". 7uf, 10/ SI .00 •• •6 .a...f, 8/ SI wit h Fig. 9 showing details. Don't forget you can ho ist one of t he se up 2 0 ft in th e air at aELECUO LYTiCS, COMPUT ER G RAD E, 6RAND N EW moment's notice in an emergency with a co u ple o f 10 ft alum inum mas ts. 72Ouf/ISO V, SI. 2S 36,CJOOyf/I SV, S2 .25 We t hen make a jump to a 14 eleme nt job12V, lI2A TRAN SFORME R SI .SO because t he red cedar boom is still o nly l O ftI N3289. .. 2ooV/ l ooA SILICON RECT IFI ER •• _ S10.OO lon g.MMS314 CLOC K CHIP WIT H SPECiFICATiO N S ;9 . 50 The eleme nts are the sa me l /8th in .7 SEGMENT LED REA DOUT . 7/10 in CHARACTER ••• s- .oc cloth esline (alu minu m, that is) and th e tim e involved for build ing should run around halfRED WIDE ANGLE LEO 'TOSL3 S .25 a day if you have all th e mat erial. The gain appears to be over 15 dB and of co urse youRED NARROw ANGLE HI _LUM LEO 'TOSL6 ....• • • • S .25 can always stac k up t wo o f them - altho ugh th e car-to p carrying and mounti ng gets quiteGREEN HI -LUM CLEAR LENS LED ' TO S11 6 • .•..••• S . SO a bit mo re difficult.ALL ORDERS POSTPAID. MIN IMUM 53 U.S., SIS FOREIGN First Mobile TestsLATEST LI STS, 10 , STAMP • • . • .• PLEASE ADO INSURANCE Wi th every t hing working (I hoped) the 14 elem ent was mounted 10 ft from th e seco nd - flo o r po rch and pointed o ut alo ng the road-rRANSFORME8RS225 VA. to th e so uth, plugged into th e tra nsmitter, and the af gain ope ned up to give someII 1V, P,i. 60 e ve. modulation. The little 3 element beam was CUSTOFMASMTASNEURFVAICCETURIN G cc 5\" ,,0 installed 5 ft ove r th e car ro of o n the ha nd-ro tat ed mo unt o f Fig. 6, plugged in to 4.;J th e receiver, and away we went._ Ipecifv II!C . volla!JII hetween 12 & 300V PO$t 0 \" 8 lbs Sou nded good as the air conditio ner motors in the shac k ca me through th e af._ ,petily sec . current between 20 & ,15 amp. . total E • I al l Q UANTITY Yes, it d oes get over 80 up here so me times, lec's 225VA Mao bu t the di fference is you run a heater first at DSCOUNT 5 o r 6 am (when I start wr iti ng !) and t he n at_ 'PKdV mount _ add Sl 00 fa, eovm _ ~dd SI .00 la' each II am you have to turn on the air condi- tio ne r. All in the same morning!HOBBY F ORM ER M F G. T,' ,m983·1555 P,O. 80X 222 _ PORT ART HUR, TEXAS 11640 73 M A G AZ INEQUAD OWNERS The perfec t ma rrioJge - your revcrue tr i-h,mdqui'd and an \" H & H RING TRANSFORMER\" . Designed specif ically lorquad\., {hi, ualun o ffers the conmum imp edance ma tch lJ\I 'ng a sing le 50oI1 m co·• • lt>edIo\" e.Now <lV.,ldble ,n th'ee new lr!tllWe'lIh t we<ltherp ,oof mode ls :• 2el~t_ boom,\"s• 3 or .. eleml!f'lt $24.95 ppH& H eng inee ring r .n. h\",. 68\"\"\" \"'IJ'''''''' I\"'\" .'iLl/d'\" I .... ..J \" j, la mirada. ('a 9116:1';' d ( \"h\" ( ; ,''','''''' Isol ated - Pad · Drill · Mill Prec iSIo n ctrcu te board construction w it hOUt etching. F in hand drill , electric drill. Simple. 'all, economical, sate. Sil \"!, , .2 0 , . 1 5, . 10 inc h d ia . W ith r ..place.able esc dril l. $6.95 ea. Ca lif. rl!s,denl1 add 5 ')1, . A F STAHLER Co PO BOX 354 CUPERTI NO, C ALIF 950'484

14\" REFLE CTOR Then at last \" CQ from WI SNN , Wal- 12\" O>RECTOR th am , Mass.,\" over 50 miles anyway . The __= :: ~ 1/4 \" receiver works well. So does the transmitter, CE\"ITER TO CE,.TER because we then had a nice QSO , my first on • 432 for quit e a while. I did a lot of switching 13\" RAOIATOR back and forth between the two bandwidthsFig. 9A. 3-element portable beam , 432 MHz, top on the receiver, with the following results.view. With the broad band i-f you can hear all the eooe stations fine but with all of them being close I 1/8\"0 0 pvc to 432, y ou can hear several at once, PIPE MAST ~ _ naturally enough. '\" 1/'\" 101/2 10118t rSPACINGS IN INCHES13 31410 7/ 8 12 1/4 7 'fu!...~ 12 1/4 13 4 12 8 107/8 12 2 1/ 13.7 11 2.15 12 12 \" \"\" II II 11 \" \" \" \" LE NGTHS IN INCHS The enhance d shado w-effect of 432 as 2: rcompared to 2 mete rs was quite no ticeable , 7•at least to yours truly with quite a fe w yearsof 2 meter beam mobile work. An 8 el- :':'O\"\".GSECT,O.eme n t, 4 high by 2 wide, will be tried soonon 4 32 o n the car. Possibly even a 4 b y 4 1. 1 RED CED AR 00U 8L EDwould be interesting o n 43 2 mobile. This one \"-IOlES 'will have to be se t back into th e middle o fth e ca r roof, though. CUl with ideas o n that ALL [ L[ IIl[NTS lI S\" ALUMINUM CLD T HSUNE .one . MOON TI NG OETAILS AS IN :5 ELE MENT 8E AM.First Evening on the Air Fig. 10. 14-element beam , 432 MHz. All 1 can say, as in th e O lson and Johnsonshows, is \" Wha t a night , what a night. \" After At six miles thro ugh trees and small hills,all, this all-so lid state rig has been some the signal was still plenty loud and sh owedmonths building, has a triple-conversion re- signs of going further , but the shadowceiver, three amplifie rs in the transmitter effec ts o f large hills prevented further testssection, and had never been o n the air yet. that da y. Also 1 wanted to get th e wh ole rigWould I even hear anyone? in to the car with one o f those 14 element jobs ready for an evening o n Pack Monad- I did. Up o n Monadn ock , with the 14 no ck Mountain, as it was Wednesday eveningelement on top of the car with a 5 ft which is 43 2 night on the East Coast at least.ex tensio n I started listening and calling, alittle early so it happened. After the usu al The sha rpness o f th e 135 kHz st ripradar signals, FM harmonics from out sho wed up well, separating even hetero-Springfield , Mass. way, an d some o d d slop- dyning statio ns. Yes, even QRM developedpy-pulse jobs at ab out len cycles (a nyone on the band as the evening wore on . The restkn ow what they are? ) finally a go od CW of the log for the evening reads, K I BFA,station came o n, peaking fine o n the beam, Westford, Mass.; WIJIZ Harvard , Mass.,pounding in , real good , \" K3 EAV portable WA 1JTK Nashua, N.II, and WI EUJ ,on e,\" I didn't raise him . Evid ently doesn 't Ty ngsboro, Mass. So the rig d oes work andlisten for fan e. it's lots of fu n. I'm not crowing, and I don 't intend to kee p th em in th e rig fo rever, but \" RCA ty pe\" 5¢ ph ono jacks and plugs are used throughout th e rig, as well a l O-year-old RG-58/U cable. Again, I'm not advo cating their use , but it sho ws what can be done o n 432 if you really try . . ..K IC Ll,FEBRUAR Y 1974 85

SUBSCRIBE\" \"TO 7:3AND IIG\"LP SeNDME ro s W1t1ER.. ~IfMP If, J\"~' /:/ o S 7.00 - 1 year o $12.00 - 2 years o $15.00 - 3 years Foreign: add $1 per year o new 0 renewalname _address call _ _city _state Z•lp _ 73 MAGAZINEPETERBOROUGH, NH 03458

In September you read a bou t Way ne's ta bu- lou s trip to Jorda n. No w, y ou t oo can be a wor ld traveler a nd ad vent u re r. Come wi th us to Jordan next May fo r o ne fu n f illed fabu lou s wee k (plu s two day s t ra veling). We'll ma ke the arra ngeme nts for yo u a nd ta ke ca re of all t he fin icky deta ils. The very low price of $69 5 (l ess tha n what you would no rmally pay for a ir fare a lo ne l will bring y ou th is onc e in a lifet ime opport u nity. Sign up no w. --- ---- • Th e beach at A qaba.• A ir t ra nsporta tio n t o a nd fr om Treasury at Petra, carved ou t of th e J ord an d eparting fro m New Yo rk rose colored rock of the mo untain.• Accomodat io ns at Jo rd a n's Inter- c o n t i n e nt al Ho tel , t h e most lu xu rio u s ho t el in J o rda n• S ig htseeing t rip s t o the ant iqu it ies (J a rash , Aq a ba , Karak, Pe t ra , Madaba, I r bid , AI Hamma , J erusalem)• Ham banquets• One of the m ost m emorable ex - perie nces you're e ver fik ely t o h a ve• J Y8 call (if you are a ham, )--------------------o Yes, s ign me up . Enclosed is my 5695 payment in fu ll\" for thi s o nce in a lifetime J ordan Tou r.o Yes, sig n me up . Enclo sed is my $ 100 dep osi t fo r this once in a lifetime Jordan Tour. I wi ll send the remaini ng 5595\" at least 30 days before o ur depa rt ure. (My 5 100 deposit is refun dable up to 30 days before the departure date.}o Yes, I would li ke a JY8 call. I have enclosed a photocopy o f my ham license. The JY8 call I wou ld lik e is : My alternate choice is:NAM E CA L L _ADDR ESS, ST AT E TE LEPHONE NO. _CI T y ZI P' _\"Ou r price is subject to ch ange in direct rela tion to the expenses we incu r dealing w i th airlines, hotels, e tc \"Those w ho have paid $695. in full will not be charged any additional am ount should the price of the tou rpackage increase. Everyone will benefit should we be ab le t o lower the price.

--- - - - - - - - - - - - - - - - - - - - - --1Fascinat in g World o f Rad io Communications $4.00Novice Class Stu dy Gu ide $4.00General Class St udy Guide $6.00Advanced Class Stud y Guide $4.00Ex t ra Class St ud y Gu ide, reduced price $5.00VHF Projects f or A m ateur & Experimenter $5.00VH F Antenna Handbo ok $3.00How to Use FM, an introduct ion $1.50FM Repeater A t las, wor ldwide w / maps $ 1.50* FM Repeater Circuits Manual $5.00* Digital Control of Repeaters', new $5.00RTT Y Handbook, radio teletype A to Z $6.00ATV An th ol ogy , fast sca n VHF TV $3.00' SST V Han dbook, new, only slow scan avail. $5.00Di od e Circuits Handboo k, ga lore $1.0073 T ransistor Circuits, all useful $1.00Transi stor Projects, mucho $3.00Solid State Proj ects $4.00IC Projects , $4.00108 Q & A , t ran smitting, receiving, ant $2.00TVI Handbook, why su ff er $1.50Coax Handbook , cables & connectors $3.00DX Handboo k, w/map $3.00World DX Map, wall size, rolled $2.00Custom DX Bearing Charts, beam headings $4.00U.S. Maps, for WAS, et c (4 ea) $1.00Call Sign Badges, for lapel, black or red $1.00Magnetic Call Signs, for autos $4.0073 Magazin e Binders, beautiful red $5.00 * Hard boun d versions avail able @ $2.00 more. All items postpaid.---- ---------- ------ BOOKS ORDER FORMName _ $ enclosedCall _ Books wanted:Address _City _State _ Zip _ 73 Magazine, Peterborough NH 03458 USA

©~~~LtrrLt©~~~~ 1 ,- ~I, ~WAAS Certificate SSTV·DXDC ., Dress up the shack with t his award forTh IS Work ed . A l- 2-way slo w scan television co m mu-mo st All Statescer-! nications with 10tificate is proof of co u ntries. Endorse-your having · ment provisions for s e pa r a te ba nds.worked 49 of the \NAAS Dated a nd signed by Wayne Gree n ,SO states. It is for E ditor and Pu b--tho se who are just --=•:::;;:;;;;;= l ish er of 73 Magazin e. Encl o se po stage for return o funable to get that QSLs. 8 Y.! x J I , ligh t green colo r, dark gree n printing, SI . _. - -------last state con- -f irmed. Printed on ,goo d paper, 8lh. xII , dated and num bered and si; ned by Wayne Green.Ordering this certificate is proof enough that you needit. Light green, bla ck printing ... .•. ...... . ....$ I.'-RRCC Certificate ';.. , All Mode DXDC ,\. ..... ..m\t;.'9Jjf ~p ~UOa~fy maf~~ ~i~ ' W ..~-=: ()~::z ~This Real RagChewers cert iflcatef All MDDE-DIDC~_n~:yA~:nW~~~i~~~~ \"~t1~is awarded o nly for to It. ~th e feat of a non-, ' : .,'stop QSO for a _ 't~tio-nSlsSewBsit-hRI1uT0Ys-cS'osurn~- ~._~C~.\!\" ..._b1_1_.-g&~n1mD_p e dod exceeding -, ...- ' J~\3six hours with no ..! -tim e out for any- - - - modes . Certificat e -- d ated and signed •--thing. Order must ~~. •\"~j_l -.:•:~-:\.-.;;; - ~ . \",.., .- ccompanied Abe a by Wayne Green , ..-:.wit h d at e ytl m e!__ Editor and Pub· ,, ~ ,(GMT) o f start /end of con tact , statio n contacted , and lisher of 73 Magazine. En clo se su ffic ien t postage fo ryour call. Signed by Wayne Gree n. Light orange co lor . r eturn of QS Ls. 8th x I I , light red co lor, blackblack pri nting $I p rinting, S 1. OX DC Certificate ' \" Understanding i.<... XYl/DMAvailable for those An unusual certifi-who prese nt proof' cate - ge t o ne andof contact (copy o f. keep your rra te )log) with 10 di~fer- ~ hap p y. An award to '5e n t c o u nt rte s. those who have theA warding this certi- good f ortune officate makes you a _ . ~ _=::;;;;;;;= having an under-member of the DX - - - - s t a n d i ng part ne rDecade C l u b . who appreciates allNumbered and da t- .'to. goo d things abouted and personally amateur radi osigned by Wayne Green, Editor and Publisher of 7 3 (stay ing up all night , s pendi ng mo ney for rigs, etc.).Magazine . Printed o n good paper, light purple co lor , Swor n sta teme nt attesting to this must be su bmitt ed . 8thblack printing, 8 th x I I , su itable for framing $ I. x I J , light blue co lo r, dark blue printing SIRITV·DXDC -\"CHC Certificate .' -;.Frame and hang Presented t o those wh o su bmit a swo rn ~this o ne above your tSstatement that the ymachine. An o pe ra- h ave never receivedting awa rd fo r those a cert ificate for ra -who h ave submi t- dio operating and ifted proo f o f 2-way they ever receive on e, they will ha teteletype commun i- .-=.c at io ns with 10 it. This certificatecou ntries. Endorse - shou Id be your firstme nt provisions ford i ff eren t ba nds.Dated and sign ed by Way ne Green, Edito r and Publisherof 73 Magaz ine . Enclose postage for re t urn of QSLs_8 Y.!x I I , ligh t blue color, black printing, SI

William N . Carver K60LG Box 1029 Livermore CA 94550TRANSISTORKEYINGCIRCUITI n the last several years a number of Tra nsistor keying of t ra nsm itters excellent electronic key designs havebeen presented to the amateur. Whet her Tra nsistors offer an excllent way to keythey have memories, dot insertion, or a the transmitter. They are extremely fast,variety of other features, they all have been quiet, have no contact bounce and willsecond-rate in one respect. The ac tual keyi ng operate almost forever. Transistors do haveof a grid-blocked tra nsmitter is u nsa t isfac- o ne practical drawback . They will not toler-tory. ate vo ltages in excess of their \"breakdown\" voltage . In t he last few years many NPNRelay keying of transmitters t ran sistors h ave bee n introd uce d whic h ca n key in excess of +350V at low cost. They Most keys use a re lay for t ra nsmitter will perform ca tho de key ing flawlessly.key ing. This allows a wide ran ge of voltagesof eit her polarity to be keyed. The re are Grid block keyi ng ca nnot be do ne q u itemany drawb acks to th is system, however. as easily . The t ran sisto r used in this service isUnless th e re lay is a h igh -s peed ty pe and is nearly always a 2N398. This is an o ldproperly driven it may not follow even germaniu m transistor, very leaky , andmoderate sending speeds wit hout bias. T he capable of switching only about - IOOV. Thefact that the integrated circuit keys do not leakage tends to cause backwave orhave a weight adjustment mea ns you ca nnot incomplete cutoff of the final amplifier incompensate for this relay problem. some transmitters. If the key-up voltage of Reed relays have been used to obtain the t ra ns mitter is higher than - I aav seve ralfaster operation. Unfortunately t he co ntactsof reed relays are delicate and te nd to weld 2N398s must be \"stacked\" to p reve nttogether or \"stick\" if a protection network tra nsis tor b reak dow n. T he usual result of t heis not co nnected across t hem. Th is net work stacki ng pro ced ure is t he lo ss of severalmust be ta ilored to t he voltage and c urre n t transistors at o ne t ime .being key ed . The 3N4888 Eve n the ree d relay has co ntact bou nce.This co ntact bounce can be overco me by Having gone through every problemusi ng a merc ury wetted reed . However, the menti oned abo ve in a series of keys usingwelding problem of dry ree d con tac ts re- t ubes, transisto rs, and finally integra tedmains and in ad ditio n the wetted reed re lays circ uits, t he nee d for a high voltage PNPmust be operated vertically at all times. Of tra nsisto r for grid-b lock keyi ng was obvio us.course all relays make a nnoyi ng clicking Silicon tra nsistors were desirable for theirnoises. low leakage current. The cost of silico n90 73 MAGAZ INE

tra nsistors capable o f withstanding a fewhun dred volts was very high - o n the o rdero f $10 a piece. Then Bob Felton K7 WLX,\" d isco vere d\" the 2N4888 . This is a siliconPNP transistor in an epoxy case. It hasvirtually no leak age and can wit hstand abo ut- 300 V in t he proper circuit. Best o f all, itcosts only ab out $ 1, less than the relay itoutperforms!Breakdown voltages \"• The 2N48 88 is guaran teed to withstand •at lea st - I SOV. While this is adequa te fo rmany transmitters, it is possibl e to ex te nd o•the b reakd o wn to over - 300 V. This isbecause o f the fac t that the voltage at which •o•a transistor breaks d own is dependent up onthe circuit into wh ich it is placed . If a ,•voltage is ap plied bet ween the collec to r andemi tte r o f a t ra nsisto r while the base lead is -- - - - - -left unconnected , the breakdo wn voltage is I Teletroncalled BVceo . If the base is th en shorted to I C O R P O R AT IO N CODE 73the emit ter and voltage is ap plied betweencollector and emit te r the breakd own voltage I 29 50 v ete-eos Memo roa l H;ghwayis called BVces. T he fac t of impo rtance to us Boheeua L.I. . N.Y , 11 716is that BVces is always higher tha n BVceo . ltmay b e as much as twice as high fo r so me I 15 161 981 ·8333transistors. For the ten 2N4888 tran sistors Ihave tested BVces ranged from - 27 S to D k it .:#80-40-20 . . . . . $29.95 plus $1 shipping- 3S0 V, qu it e sufficien t to key anyt ransmit ter in my experie nce. I D c oils only (pair of 4\" dia. special coils) $17.951 In a practical circuit the base o f t he2N48 88 will be sho rte d to th e emit te r b y aseco nd transisto r to achieve the higherBVces rating. T he keying would be inverte dby this two-transistor circuit so a th irdtransisto r is ne ed ed to re t u rn keying to t hesame se nse as t hat of a relay . TO NE GATIVE PCMtER SVPPL'r' - 6 TO -20 VOl. TS TO BASE IN4°O:I 220 I plus $1 shipping IcON NECTION '0' 1. 8 I< I NY res ident s add 7% sales tax _I OF OLO 2N398 OR '\" I name I Y DRIVING ISTOR '\" '0'c Xr.lTR I _I\" .~... 21 1< Q'~ Q' ::;¥ I add ress I 2N4888 I I state __ ztp _ I city I r7 I IFig. 1. Grid block k eying the PNP transistor k eys. I Enclose check wi th order- I L We ship UPS upon receipt o f order ----------FE BRU A R Y 1974 91

·--- -- - - - - - - - - - - - - - - - - - - - - - - - - - 1The 2N4888 in transistor keys tOO K Figure I shows t he three-tra nsis to r circuit .... T .... 1Ilas it wou ld be co nnected to a PNP t ransistor BVCES 0 BVCEO ~ AO.AlST Alll.Ekey . The original key circuit is immaterial, POW'E fl 9..1PP1..Y L- ~,A }----+usually consisting of 2N107 or 2N404 +transistors. The base of Q I is connected in --lplace of the relay keying transisto r or the Fig. 2. Testing the breakdown ~vHages of the2N398. 2N4888. AU three new transistors are silicon. Q 1 prevent damage to the transistor : power supply voltage should be raised slowly whileand 02 were 2N3638, but MPS3638, watching the microammeter like a hawk.2N4125, 2N3702, 2N3703, or similar The moment a microampere or two istransistors should work just as well. Q3 is indicated on the meter, read the VTYM andthe 2N4888. Resistor values are not critical remove the test voltage. High voltage transistors have different failure modes thanand the circuit works with the usual power the low voltage types and appreciable current should not be allowed to flow.supply voltages found in keys of this type. To prevent inadvertent application of Adapting Ie keys with the 2N4888positive voltages to the 2N4888, a silicon Figure 3 shows the 2N4888 in a simplepower diode was placed in series with the integrated circuit key, the \"Micro-TO\"collector. To prevent current surges from described in the August 1967 issue of QST.fusing the 2N4888, a 220n resistor is also Common IC's such as those used in theplaced in series with the collector. Micro-TO require +3.6V. The PN P nature of thc 2N4888 demands negative voltages. The ac switch of the key should have two These conflicting requireme nts can besections. The added section, labeled SI B, satisfied without adding another powershorts the 2N4888 collector when the power supply by changing the grou nd referenceswitch is turned off. This protects the terminal of the whole Micro-TO circuit.transistor if the transmitter is left o n and the All points which were originally groundedkey is turned off. Remember, unless the (including the key lever, power supply transformer center tap , and filter capacito rs)2N4888 has its base an d emitte r shorted by are bussed together and lifted from chassis02 t he breakdown voltage will be on lyBVceo. In such a case if the key -up voltage ground . This becomes the -3.6V terminalof the transmitter exceeds - 150 Y t he2N4888 could be damaged . Sl B prevents for powering the new circuitry. All pointsthis possibility . which were formerly +3 .6V are grounded to the chassis. Since the ground terminals and Before usi ng the key, measure the voltage +3.6Y terminals of the circuit are probablybetween the base and emitter of 03 with buss wires on a printed circuit or perforatedkey power turned on, but not operating the board the change requires moving only a fewkey lever. The voltage should be less than a wires. After this change the integrated circuits are, in effect. \"standing on theirfew tenths of a volt . Next, with a VTVM, heads.\" They don't know the difference, however, and operate just as before. Themeasure the key -up voltage of the PNP transistors see the - 3 .6 V they requiretransmitter. Since this may depend upon so everyone is happy . Total cost of the \"spotting\" or tune positions be sure to look conversion is held to about $2 .50 by this for such differences. If the highest voltage trick . does not exceed - 250 Y plug in the key andstart enjoying transistor keying. If your voltage lies between - 250 and -325Y it is a good idea to buy several 2N4888 transistors and test them to find one having highest breakdown voltage. Figure 2 shows a test setup which can be used to test BYceo and BYces. The test should be performed carefully as follows to92 73 MAGAZ INE

aOTTo'\" VIEW' 2N4SIIi-_FLAT SlOE COLLECTOR -~ EMITTER0 .00d:!;: ..~ ' , ,;;:;:C3\"'C4+ BASE\"'\" c ! .OO~ I I I I OL D GROU ND Ir--~r---- --- - - - - I SIB I NOW - 3.6 V • ; ~ I ,. 220 ., I10 , ,T I ...I ¥: 2 •• : IN4004 \" i 3,4,6 3,4 ,6 rc I ., '~ I \"\" e\"2 IXtolTR I aa 2 N4 8 88 ~ I.' I I .2 ~ 10 ' I '\" I I- I I L! _ ____ _________ JI /, 7 +3.6 oj ~ \"'-\"-0ADDED CIRCUITRY NOW GROUNDED OLD + 3 ,0 NOT CHANGED Fig. 3. Grid block k eyin g with the \"Micro -TO.\" Fo ur 0 .00 I IlF bypass capacito rs are used wit h a PlY of about 400Y co uld bein the Micro-TO . Two are u sed to by pass the su bstit u ted for th e I N4004 .ac line , two bypass th e key lever co ntacts.These bypass capacitors should be e x clud ed Testing pro cedure fo r both key andfrom the ground change: they remain transmitter are the same as was describ ed fo rbetween their respective wires and grou nd in the tra nsis to r key modifi cation .order to prevent stray rf from ente ri ng thekey. Othe r ty pes of IC keys can use th e 2N4 888 by cha nging th e grou nd referen ce as No te that Fig. 3 d oes not sho w all of t he was d one here with th e Micro-TO . MyMicro-TO circuitry, just th e power sup ply in tegra ted iambimatic key ( II KEY) uses thisa n d p o wer co nnections o f the lCs, ide ntical tec hnique and cir cu it.Interconnect ing .wires between portions o fthe circuit were not change d in any way Finding the 2N4888from the original schema tic . The 2N4888 is a Fairchild resis tor and QI is a silico n NPN transistor. Almo st may be hard to find . A letter to Fairchildanyt hing will work h ere , the 2N3 392-93-94 Marketing Services, Bo x 1058 , Mountainseries, 2N3 704-QS -Q6 series, 2N S183, and Vie w, Califo rn ia , ask ing fo r th eir \"Fairchild2N70 6 being suitable t ypes which are very Stocking Dis tribu to rs List \" will give yo u ainexpensive. Q2 is a silico n PNP , 2N363 8 or so urce fo r their tra nsistors and integratedequivalent types discu essed in the tra nsistor cir cuits.key adaptation. Resistors are not critical andanything wit hin 20% o f the ind icated valu es Resultswill be fine . I've used two homebrew transmitters, an Th e prote ctive diode , resist or , and switch Apache , and an SBIOI with fo ur d ifferentare used in the IC key mo difica tio n ju st as keys using the 2 N4 88 8 . Results have beenthey were used in the tra nsisto r key uniformly successful. Transisto r keying ismodification . Again , any silicon power diode quick and fla wless - a definite improvement over the clicke ty-clack of relay s. ... K 60LGFEBRUARY 1974 93

:2: Name Send To: A LEXANDER MANUFACTURING CO.a: BO X 1645 MASO N CITY , IOWA 50401ou, Address Se nd me _ _ te n packs at 530.80 ea.a: Tot al Encl osedow Cityoa: State------------------------------- BUVANICKEL-CADMIUM - I • Th ese fast c ha rge Nickel- Cadmium s are just th e tic ket for your han d unit. You can charge th em up as ofte n as you like. Buy two sets and keep one cha rged up for eme rge ncy purposes . . . a re- fill , as it we re . In this wa y you'll have twice the use from your hand unit and never be out of action . Also have huge stoc k o f Nickl e-Cadm ium AA size Pen- li t es, $1.50 eac h., Buy Two! $30.80 ea. ALEXANDER manufacturing co. Box 1645· Mason city, Iowa 50401 Phone (515) 423-8955/ TWX 910·523·697894 73 M A GA Z IN E

USING Warren MacDowell W2AOO 11080 Transit Road East Amherst NY 1405 1 A SE VEN -SEGM ENT READOUT WITH A NIXIE DRIVE RD uri ng the construction of an elec tronic merals of the Nix ie tubes. Therefore it was clo ck o r frequency counter, the type necessary to come up with a proper diodeof readout e mp loyed can be a deciding matri x th at wo uld interfa ce the SN 7441fact or in the o vera ll price of the unit. The a nd SI'-733.LED (Light Emitt ing Diode ) type of sevensegme nt readout is quite a bit more expen- We were fo rtu nate enough to find somesive th an th o se o f the \"Nixie\" type. The computer boards o n the surp lus market thatdriver integrated circu it fo r the LED read out contained o ver 300 glass bead type of silicongenerally is more expensive than the driver switching diod es. These boards sold for lessfor the \" Nixie \" tubes. Most o f the LED than $ 1 each. The silicon diodes werereadouts are low voltage devices (appro xim- pressed into service and worked very wellately 5 V) and work with a lo w voltage type without a single failure . The voltage acrossof driver such as the Texas InstrumentsSN74471 C. r '- i2 3 4 5 6 7 6 '3 10 REAOOJT ,..j NO\"S. One o f the better deals we have dis-covered is the SI'- 733 readout which is IImanufactured by Sperry Rand. The SI'-733is used by Heathkit in their new IC-2008A I 8 9 13 ~ 11 01 2 ~calculator and sells for about $7 .35 throughHeathkit outlets. Of c ourse these are in- SN74 41 ' Ie PIN CONNECTONStended for replacement use in the calcula-tors. The SI'-733 co nta ins three com ple te Areadouts in a single fl at enclosure . Therefore ,the price per readout comes to $2 .45 each. EF'l-n!\"\"The SI'-73 3 is a seven seg me n t d evice ;however. it is not compatible with either the ANOOEJ' 22I<, II2 WSN7447 which is a low voltage seven seg-ment driver, o r the SN744 1 which drives 8'individual numeric high voltage \"Nixie\"tubes. The SI'-733 requires a pproxima tely 200VDC200V dc o n e ach of th e seven segme n tsthrough a 2 2,000 n !hW cu rre n t lim iting F ig. 1.resistor in o rder to illuminate the segments. Due to the reasonable price and compac t-ness of th e SP-73 3 (4.2 x 2 .8 x 0. 5 em ) wewere prompted to try and make it co m-patible with a \"high voltage\" Nix ie driversu ch as the SN 744 1. The SN 7441 wasconstructed to ground only the single nu-FEBRUARY 1974 95

FRONT VIEW T AAA F G B FI G B F G B EUC E C EU DDD REAR VIEW $1'1.00 A AA -Q:H~\G\1AL 0 00 -iCO~FRCEOPNE1AR1EORLS Bo of Bo of Bo of oG oG oG Co oE Co oE Co oE oD oD oD 0 0 • 0 0 0 ANODE ANODE ANODE Fjg. 2. SP-733 pin numbers. Here's the book for every ham who the diodes in the matrix varies from lO-15Y with a 200V potential on the SP-733's. wants 0 design and build a digital Another garden variety of silicon diode that may be used are those that are sold by Radio repeater control system (or who Shack in packs of SO. These are untested and should be checked before placing them in wants to just think about doing the matrix. We found that usually one out of the 50 would be shorted or open. that). Contains sections on repeat- Figure I illustrates the printed board ers, basic logic functions, logic cir- construction. OUf boards measure 5 x 7.5 em and could have been made such smaller cuit design, control systems, sup- by standing the diodes on end. Use double sided PC board stock (copper plated on both port circuits, mobile installations, sides) and follow the Fig . I pattern. The solid lines indicate top side conductor lines touch tone, plus a special section on and the dotted indicate bottom conductors. a \"mini\" repeater control system. The easiest way to drill the double sided board so that the holes match after etching 224 pages. is to hold the board up to a lamp so that the bottom lines show through the board . Mark Hardcover $7.00 Paperback $5.00 your drill hole positions with a pencil and then drill. Figure 2 illustrates the SP-733r----------------------- segment pin connections.: 73 Magazine, Peterborough NH 03458 The completed diode matrix units are thin and can be easily stacked in a small area.I Enclosed is $ . Please send _ Dhard-II cover ($7)/Dpaperback ($5) copies of Do not hesitate to experiment with dif- ferent types of silicon diodes. Almost anyI \"Digital Control of Repeaters\" to: high speed switching type of diode will function.I Name Call __ . . .W2AOOI _ 73 MAGAZINE: AddressI City _I ZIP II State ,II 96

(Continued from page 7)p rivileges in the fi rst place. proposal although it was no secret FCC had o ffered CW privileges only to the Techs. either as a shared proposi-On the othe r hand , CBers are not that many Techs were far more tion with the Novices, or on some othe r segment of the HF bands, thererequired to do anyth ing more than to i n t ere s t e d i n be com i n g are not many hams who wou ld have o bjected to it. It has always seemedfil e an application plus th e req uired commu nicators th an in being bu ilders incomp rehensible to this writer that the FCC has not seen fit to providefee . In many cases it has been sh own and ex pe r im e n te rs, (for which some CW space for the express pur- pose o f a iding Techs wh o wished tothat these applicat ions have been and purp ose the Tech class was originally upgrade themselves by part icip ating in o n-the-air CW operation. The p resentare being falsif ied . It has been a very established). As it now stands, Tec hs CW privilege they are assigned simp ly has an insuffic ient number of CWco mmo n practice for persons to sign have to struggle in o rder to get enoughfor o th ers. often offspring wh ose in- code under their belts to hand le thesufficient years would disqualify req uired speed and facility .them A person who signs such a false At one point an ill-advised proposalapplication is guilty of a serious was made which would have grantedc rime ; t hat of attesting to untru e Techs p ho ne privileges only in th e 28sta teme nts, to wit: that he (the signa- MHz ba nd, but no CW was included .t o r) is ap p lying fo r operating LEAKY LI NES o pposed th is on the operators to be consid ered adequate.p rivileges, when in reality he is fili ng basis th at such a free gran t, with no Having fa iled to perceive anyfo r an individual who is not eligible. code exam invo lved, would amount to valid ity in adopting th is and otherThroujjl this means an out-and-out an unconscionable breach of faith re a so n a b le plans t h a t wou ldexamp le of lawless behavior on the with those who had been forced to effectively improve and consolidatepart of his parent or othe r adult is the accept the validity of the ince ntive the amateur service, one wonders byjuvenile's init ial imp ression regard ing l icensi ng pri nciple, whic h had what manner of \"double-th ink\" thethe relat ive unimportance of observing previously been piously p ushed by FCC finds merit in a p roposal to handthe commu nicatio n laws and obey ing both the FCC and th e A RR L, under CB ano the r port ion of the spectrumt hem. Thi s is a compelli ng impression the pretext that it was altogether o n a silver p latter, wh ich it willwhich often molds and sets his p roper for amateurs to justify their undoubtedly destroy, just as theyconduct from that time forward . If privilege by conti nuing to advance destroyed their present band. There isthe adult in question has been able to the ir skills under pain of (again.. .it not a scint ill a of reasonable evidencefalsify the applicatio n document with seems to rear its head as a solution for to show that a relocation to the 220such ease, why shou ld the rec ipient of ev~ry p ro blem. . 1 under pain, as I MHz band would ca use them to mendthe license view legal operating sa id , ~ f a lo s s o f operating the ir ways and begin to observeregulations with any respect? .trequencies ! Most hams were so regul at io ns wh ich t hey have never bef ore heeded. . .d o not observe t h o r o u ghly brainwashed and so now...and are no t even remote ly taking serio usly.This lamentable cond ition wh ich battered from pillar to post, that theyhas always infecte d the Citizens Band, finally concu rred and accepted theis a direc t outgrowth of the FCC's d octr ine of incentive licensing. Fine! Another crit icism ca n be levelled.utter failure to u nderstand that they But at the time when it was proposed In a cou ntry in which financial profitmust insist upon more tha n just the that this hank y-panky about giving is the name of the game, it wou ld beme re filing of an application, with the Techs a back-doo r ent rance into extremel y na ive to imagine tha t such aa bso lute ly no furth er q uali fying p rivileges on 29.5-29.7 MHz, most of p roposal could grow ou t of the sale idea t hat i t wou ld really becrite ria. Though it is ent ire ly possib le us were o f th e opinio n tha t such a meritorious fro m the aspect of valid need. We all know whose brainstormfo r admi nistrative miscalcu latio ns to grant wo uld have been an abrogation th is proposal was.. .there is no doubtoccu r whe n new mo des o r serv ices are of the incentive licensing princip le,first inaugu rated, to fait t o take and wou ld have afforded unfairforceful corrective measures when the preferential favor to th e d isadvantage that i t wa s s pawned by thee rror is discovered, is a monumental of all who had been forced into m a n u f ac t u rers of elect ronicdereliction of responsibility. CB, with working hard enough to upgrade. equipment, who stand to reap millionsall its evils and problems, is the Literally hordes of Technicians in windfall profits, should t hecreature o f the FCC, and they ca nnot wrote indignant protests to this p roposa l be app roved. The verybla me anyone for th e mess but magazine, accusing th is write r of mo ment it becomes okayed, sales ofthemselves. Why th en, should we p rejudice, unfa irness and a score of new equ ipment will begin to burgeon,ama teu rs be made to pay for the other selfish motives. It was claimed and the eno rmo us sales figu res whichmistake? We paid dearly once, with that the article was aimed solely at ensue are likely to make the o ld CBthe loss of one of our bands. Are we slamming the door o f equal business look like penny-ante stuff! Inexpected to pay all over again, simply opp ortunity in the fa ces o f order to avo id being misunderstood,because the FC C r e f us es to Technicians. Well , of course, that door let's get th is clear, at least . I certainlyacknowl edge t hat CB has been a has always been possible to open. do not begrudge manufacturers theirmise rable fiasco? Why d on't they Th ousands o f Techs had successfu lly right to bu ild and se ll gear. But itmove th e CBers to some body else's u pgraded their license th ro ugh the seems that in this case it was the mainband, rather than to yet another ham o rdinary p rocess o f study ing th eir object in proposi ng th e cha nge. Andband? code and theory, then going to an while th e economic aim may be A long time ago this co rrespondent FCC exami ning point and passing the perfectly acceptab le, I thin k the losssuggested in the pages of this test . We s i m p ly happen ed of an ama teu r band is mum to o h igh amagaz ine that if the FCC was truly to feel strongl y that any Tech wh o price for us to be forced to pay! Ifin t ere sted in some constructive rea ll y felt the desire to ex tend his this change were motivated primarilysuggestio ns, one o f the very best opera ting privileges could easily d o so fo r the purpose of improving and benefiti ng th e rad io spect rum, th enwo uld be the granting of CW privileges by exerting himself to tha t limite dsomewhe re o n the HF ba nds for the extent, and if he was unwilling to secondarily, fo r assisting the elec-Technicians so that those who might exert th is sma ll effort, he certainly did tronics ind ustry to reap a harvest,desire to u pgrad e thei r tickets would not deserve p referential treatment. We then the p ro posa l migh t be viewed asbe afforded an opportunity to do so termed the proposal \" giving a lollipop acceptable by some. But the move iswith more ease. The Commission to a kid at the barber shop .\" advantageo us to ma nufacturers andevidently recognized no me rit in this I can state confi den tly th at if the the CBers alone. Th e amateurs stand (Continued on page 98)FEBRUA RY 1973 97

(Con tinued (rom page 97) But never, from th e outset, was a(Continued (rom page 12) o nly to lose stili ano the r slice o f hobby-type operation envisio ned o r frequency. And what will we gain? co nte mplate d. Amateur radio has Precisely nothinq !FCC HEARING REPORT ex iste d for that pu rpose, and it has \" But listen ,\" say the proponen ts of always been availab le for those whoCopies o f t he three page report the grab . \" This partic u lar band is not wer e i n te rested fro m a hobbymade to the FCC Commissioners o n even being used.\" They try to argue s ta ndpoi nt . T o c ha nge ou rthe need fo r rep eal of th e repeate r that th e idle freq uencies should be fundamental understand ing now, andregulations are avai lable from 73 re-assigned to people who will make take the pos itio n that radioMagazi ne , Pe t er b o r o u gh NH better use of th em. We once made an commu nica tio ns are two03458 . .. send sese. Many amateurs analogy.. .supposing you are storing hobbies. ..o ne, a group of tec hnicallywho are no t well informed on the you r win te r overcoat in a cedar c loset. minded devotees of an ongoi ngseriousness of the impact of the new All of a sudden, in the middle of July, science, who are vitally concernedregulations would do well to read th is some guy waltzes in and takes your with being a part of its growth. . .andrepo rt and see why it is so important overcoat away, using as justification two, a g roup of unconcernedthat these regs be changed . the argume nt th at you aren 't using it. dilletantes whose only purpose is to You'd surely feel a sense of outrage. contact one another in a sort of And rightly so! This rat ionale is as surrogate wireless telephone system, CONGRESS REPORT cockeyed as it can be. The coat is without the slightest inclination toThere are still copies of the Con- stored in the closet to be used at some probe into the theoretical and thegress Newsletter - a report written fo r later time, when conditions warraant. public service aspects of the thing, isyou to send along to your Senator or Simila rly, the 220 MHz band seems an abrogation of a concept which hasCongressma n, together with a covering likely to become more important to earned the respect and confidence ofletter, aski ng for his influence in amateurs in the future because of the all thou~tful people, throu~out thehelping amateur rad io fight off the rapid growth of VHF repeater tech- world . No matter how the FCC seeksnew restrictive regulations and the n iques. It could easily become one of to rationalize th is projected change, itassau lts on our 220 and 450 MHz ham rad io's most val uable assets. like can never explain away the ho rrid th e overcoat in the closet , it will serve inconsistency embodied in the veryba nds . its purpose in due course. It would be character and nature of the idea. On 73 VS IRS a tragic error to hand it over without a the one hand it licenses a serviceTh e first of a series of newsletters struggle to opportu nists who will which has always risen to everycovering this inte resting development make it a shambles, and to entre- c ha llenge, and has justified itsis in pri nt and availab le if you send a preneu rs who will profit by the mis- existe nce b y pa rt icipa ti ng in use .sase. If there is enough inte rest in the thousands o f public service activities.inside d ope o n the IAS and the whole While I'm o n the su bject of On the other hand it has created at ax situation, thi s series o f letters will mare's nest . ..a Pand ora's Box of atro-eventua lly be put into bo ok form. repeaters, a haunting th ought races cious ho rro rs, which has never abidedLooking into the admi nistration of through my head. Could it possibly be by th e conce pts wh ich gave it life, hasth e IAS has turned out to be abo ut created p ro blems of its own, andlike turning over an innoce nt looking that the FCC, an tic ipating th e which constitutes an insolu ble mess solog and find ing all so rts of scrambl ing vi le t hat nobod y can dec id e what canmaggots a nd black beetl es scurryi ng advancing repeater technology, and be do ne to clea r it up! Th en they have realizing that sooner o r later it must the unutterable gall to suggest thataro und. this ca ncer mu st be allowed to spread inevitably become indispensable to 220 MH z, has chose n to implement its idiotic and totally ill ogical position vis-a-v is th e Docket wh ich pertains to repeaters, in order to c reate t he to anothe r part of th e spectrum. fundame ntal st ructure within whose Citizens Band has been a failure o n SUPERLICENsm f ramework it can mai ntai n the 27 MHz. Wherever they chose to put A note from WA5CON suggests condit io n of d isuse on that band? In it, it will continue to be a fiasco,some sort of special amateu r call this manner the Commission could unless they stiffen the req uiremen tsprefix for cos who have managed to almost guaran tee that when the and begin to en force some adult re- proper time came along , and itpass all FCC exams. Tic ket collectors decided to reassign 220 to another sponsibility o nto the shou lders ofwill have a tou gh job keep ing up with these freeloadi ng parasi tes who have service, it could poi nt to the fact thatthis c hap who now has first ph one amateu rs are not utilizing it, and that corrupted it. Th ev must be madewith radar endorsement, first te le- accou n table, finally, fo r theirgraph wit h radar , six month s mar itime therefore it would be a justifiable undisc iplined excesses. But this canservice endorsement, aircraft tele- re a ssignment. In these days of never happen so lo ng as a na ivegraph, and ama teu r ext ra class. With elaborcete fi nagling on the part of Federal Commu nications Commi ssionall those licenses on the wall is there govern ment agencies and bu reaus, and co ntinues to believe i n t heany room for QSL cards? And howdo all sorts of conspiracies and coverups. preposterous notion that the presentyou decide which band to use when th is sort of a cabalistic arrangement form of loose criteria in Iicensing andyou have a spare moment between would not be as bizarre and arcane as operational regulations and it appears on the surface. We could enforcement should be maintained.tests? very easily find ourselves right smack It's a ce rtainty that this proposal dab in the middle of our own little represents a giant step backward for WANTS TO BU Y Wate rgate. the world of amateur radio. And everyAll types o f m ilitary elecuo nM:s eq u ip- I' m perfectly wi lling to grant the ham should be awa re o f his or herment and parts.Can collect for t:3sh offer. fact that in the beginning, back in the solemn obligation to make known to - - - - - -- - 4 0's when it was first proposed, CB the Co mmission exactly how he or she sounded li ke a reaso nably good idea. feels about the matter. Thi s one issue SPACE ELECTRO NICS d,visi a n a t And I' m further wi lli ng to agree that is probably the most important single there are many legitimate users of that piece of legislative action an amateur- - - -MILITARY ELECTR ONI CS CORP. - -- -76 8rOOkslde Or\"\"e. Uppeor Saddl. R\"\"OI'f service who need and deserve a band can take, providi ng h is hobby mea nsNew J... wy 07458 f 12011 32 7-1640 of freq uencies in whic h to operate. any thi ng at all to him. 73 de K2AGZ98 73 MAGAZINE