ham i 1 k radio the world's fines1_ Amateur linear amplifie We think it is ...a nd we 'think you'll agree with us. Ever since we made our first Amateur amplifier almost 20years ago, our goal has been to make the finest, most rugged and reliable amplifier possible. Now with the 3~ Classic we have accomplished this. It contains all of the famous Henry amplifier features plus the magnificent 8877 tube, rugged heavy duty power supply components and advanced antenna switch relay for semi break-in on CW. This is the amplifier of every Amateur's dreams! .\rrt~iect 10 I (:c rypc ~rcccplar>rc The 3K Classic/X with heavy duty power supply and 10 meter operation is available for sale outside the USA where FCC type acceptance is not required. 'h2/ K Cia s sn c The 2K Classic represents the culmination of years of experience in developing, manufacturing and improving the 2K series. It remainsasalwaysa "workhorse", engineered and built to loaf along at full legal power for days or weeks without rest. A look inside shows why! It is truly a "Classic" amateur amplifier. Heavy duty, top quality components along with its rugged construction assures you trouble free operation. It will put your signal on the air with greater strength and clarity than you ever dreamed possible. The 2K Classic operates on all Amateur bands, 80 through 15 meters (export models include 10 meters). Price 51295.00 145-, y<p-s. .. Another fine member of the famous Henry Radio family of superlor ampllflen. And we're stlll convlnced that It's the world's flnest llnear In Its class. The 1KD-5 was designed for the amateur who wants the quallty and dependablllty of the 2KD-5 and 2K-4, who may prefer thermaller size, llghter welght and lower prlce and who wlll settle for a llttle less power. But make no mlstake, the 1KD-5 is no slouch. Its 1200 watt PEP lnput (700 watt PEP nominal output) along with Its superb operatlng characteristics wlll still punch out clean ... powerful signals slgnals you'll be proud of. Compare Its speclflcatlons. Its features and Its flne components and we're sure you wlll agree that the IUD-5 is a superb value at only $695. - , 5 , We have been suggesting that you look lnslde any ampllller before you 1 'd buy It. We hope that YOU wlll. If you "llft the Ild" on a 2KD-5 you wlll see ... only the hlghest quallty, heavy duty components and careful workmanshlp attributes that promlse a long llfeotcontlnous operation In any mode at full legal power. The 2KD-5 Ira2 000 watt PEP lnput (1200 watt PEP nominal output) RF llnear ampllfler, covering the 80,40,20, and 15 meter amateur bands. It operates wlth two Elmac 3-5002 glass envelope triodes and a PI-L plate clrcult wlth a rotary sllver plated tank coll. Prlce $945. Henry amateur amplifiers are available from select dealers throughout the U.S. And don't ,*P ... s b forget the rest of the Henry family of amateur amplifiers the Tempo 2002 high power VHF amplifier and the broad line of topquality solid state amplifiers. Henry Radio also offers the 4K- Ultra and 3K ClassicfX su~erbhi a., h D. ower H.F. amolifiers and a broad line of commercial FCC AP 4 IC type accepted amplifiers for two way FM commun~cattonsc ovenng the range to SOOMHz. 2050 S. Bundy Dr., Los ACnB e les, CA 90025 213 820-1234 931 N. Eucl~d,A nahelm. 92801 1714l 772-9200 CpF Butler, M~ssour6~47 30 816 679-3127 TOLL FREE OROER NUMBER: IBM)I 421-6831 For all states except Caltlorn~a Calif res~dentsp lease call collect on our regular numbers MFJ-1200 GENERAL PURPOSE MFJ SWW CW Computer Interface Connects computer to transceiver. Converts received audio MFJ SWRlWattrneter to TTLIRS-232. Allows computer to key transmitter. For reads SWR, forward, reflect- use with your computer and CW KeyboardlReader program. ed Dower from 1.8-30 MHz. Allows your rig to "talk CW" to your MFJ-814 New low cost in-line HF SWRIWanmelr. MFJ-814 lets you rnonltor SWR, forward, ...u (I?* reflected averacle power ~n 2 ranqes from 1.8 to 30 MHz. Read 20012000 watts forward. 201200 watts reflected power. SWR. 1:l-6:l. A personal computer with an appropriate aluminum cabinet Requires 6 9 VAC or 110 VAC program can give you a complete and very ver- with optional AC adapter. MFJ.1309AC. $9.95. Easy push-button switch opcntion: has power1 - satile CW KeyboardlReader. But you st111 need 'Order from MFJ and try it no obligation. If SWR, highllow range, forwardlreflected push- interface electronics to provide compatible signals not del~ghted, return 11 within 30 days for refund button sw~tches.S WR sens~tivltyc ontrol. between your transce~vera nd computer. (less sh~pp~ng)O. ne year unconditional guarantee. Lighted meter (requires 12V). Rugged alumi. The MFJ-1200 CW Computer Interface pro- Older today. Call toll free 800.647 1800. Charge mrm eggshell white, black cabinet. 6l/4~3~kx4~/4". cesses (no~seI lrnlts, filters, detects, post filters. VISA, MC or mail check, money order for $69.95 SO-239 coax connectors. 2 color meter scale. shapes, level sh~fts)t he received CW audio from lor MFJ-t 200 plus $4.00 sh~ppinga nd handl~ng. MFJ W F SWRlWattmeterl your transceiver to provlde a clean computer Use this MFJ-1200 to enjoy your computer as compatible TTL or RS.232 level. Field Strength Meters H also takes the keyboard generated CW and drives high keying circuits to key derlrepalr status Also call 601-323-5869 outside your tube or solid state transmitter (.300 V, + continental USA and In MISSISSIPPI, 10 mA max; 300 V, 100 mA max). Has tuning, transmit. and "ON" LEDs. Revene- ENTERPRISES, normal sw~tchi nverts output level to computer. INCORPORATED New low cost VHF operating aids. ONIOFF switch. 6x13/4x3 in. Black. eggshell white BOX 494, ~i~slssipSptait e. MS 39762 MFJ.812, $29.95: Read SWR from 14 to d 170 MHz to mon~tora ntenna and feedlines. Read forward and reflected power at 2 meters (144-148 MHz). 2 scales (30 and 300 watts). MFJ DIGI-DIAL ADAPTER Read nlatlve field stnngth from 1 to 170 MHz. Bind~ng post lor held strength antenna turns your frequency counter into a Easy push-bunon operation: has forwardlre flected and SWRlfield strength push-buttons DIGITAL FREQ. READOUT Aluminum eggshell while, black cabinet. 41/4~21/4~23/4"S.O 239. 2 color meter scale. 1 Calibrate control MFJ-810. $24.95: similar to MFJ.812 les! 0 field strength function. , $ 95 compensates for heterodyne MFJZry" 300 W and MFJ DIGI-DIAL error5s and 9mode offsets. 1 K Dummy Loads. mom "~OIIALE e,, .ma - CArLIBnRAT E MOOEL MFJ-210 Air cooled, non-inductive 50 ohm resistor ir perlwated rnetl hous~nqw ith S0239 connectors / The MFJ 41-DM Adapter turns your ireGcy with optional MFJ-1312 AC adapter, $9.95. Full load for 30 seconds, de-rat~ngc urves t( counter ~ntoa n accurate digital frequency readout Order MFJ-210 for any rig with 5.5.5 MH: 5 minutes. MFJ-260 (300 W). SWR: t.l:t t( for your transce~ver. Connects between external VFO (TS-520. S. SE: TR-3. 4; HW.100. 101; 30 MHz, 1.5.1 for 30 160 MHz. 2l/zx2lhx7". VFO jack and frequency counter. SB-l0 1. 102; Tritons; etc.) Order MFJ-211 for MFJ-262 (1KW). SWR 1.5:l-30 MHz. 3x3~13". Counter gives dinct frequency nadout to right Yaesu FT.101 series (8.7 to 9.2 MHz VFO). - MFJ.10. 3 foot coax with connectors. $4.95. of dec~malf or 7, 14, 21, 28 MHz bands. Mentally Order hnm MFJ and try it no obligation. If replace dig~tst o left of decimal w~thM Hz band not delighted, return 11 within 30 days for refund ~lderfromM FJ and try it. If not del~qhted. as you do now with your analog dial. For the 3.5 (less sh~pping).m year unconditional g@rante& return w~th~3n0 days for refund (less sh~pp~ng). and 28.5 MHz band ignore d~g~ttos left of deck Order today. Call toll free 800 647-18 00. Charge One year unconditional guarantee. ma1 and mentally add 3.5 or 28.5 MHz. respec. VISA. MC or mail check, money order for $59 95 Order youn today. Call ton free 800-647-1800. lively, to counter reading. plus $4.00 shipping for MFJ-210 or MFJ-211. Charqe VISA. MC Or mall check, money order. Calibnte for each band and mode (CW. USB. Don't wail anv longer to eniov diaital readout, Add $4 00 each for sh~pp~naan d handl~nq. LSB. AM) to compensate for heterodyne oscillator errors (does not read CW transm~to ffset). C.111 601 323 5869 for techn~cal ~nlorrnation,o r Digital mixer Inverts VFO frequency to give C,ill 601 323 58119 lor lechnlcal ~nlor~nal~oorn derlrepalr status Also call 601 323 5869 out- correct frequency readout. NormallReverse swltch derlrepa~rs tatus Also call 601 323 5869 outs~df s~dac nntinental USA and ~n M~ssiss~oo~. gives d~rectV FO lrequency readout (for some rigs rnnbnental USA and ~n MISSISSIDOI on some bands, like Drake TR-4). RF buffer amplifier. Crystal reference oscillator. I WOfl sw~tch." On" LEO. Black, eggshell white al. Box 494. Mississippi State. MS 39762 \ pahinet .73/rxll/rx3'/r" 9-18 VDC or 110 VAC Box 494. Mississiool State. MS 39762 More Details?C HECK-OFF Page 94 October 1981 1 I lnstant ~ccessD igital I lnstant Fingertip ~u;in~-~o More Knobs! W 6 Memories for Any Mode (AM,SSBICW, & FM) A Enter Button F SSBlCW Compensator Dual PLL Frequency Synthesized-No Drift! B Signal Strength G Execute Bar Indicator C Liquid Crystal Display H Manual Tuning Buttons A WHOLE NEW BREED OF RADIO IS HERE NOW! No other D Memory Preset Buttons I Scan short wave receiver comb~ness o many advanced features for both operating convenlence and high performance as does the E Antenna Adjustment J HighlLow Limit Buttons new Sony ICF-2001. Once you have operated th~se xcit~ngn ew Dial radio, you'll be spoiled forever1 D~recat ccess tuning elim~nates conventional tunina knobs and dials with a convenient dia~tal keyboard and ~iqu1C2r ystal D~splay(L CD) for accurate freqien. OPERATIONAL FEATURES cy readout to w~thin1 KHz. lnstant f~ngerlipt uning. up to 8 INSTANT FINGERTIP TUNING w~thth e calculator-type key board memory presets, and continuous scanning features make the enables the operator to have lnstant access to any frequency in ICF-2001 the ultimate in convenlence. the LW. MW. SW, and FM bands. And the LCD digital frequency Compare the following features against any receiver currently d~splay confirms the exact, drift.free signal be~ngr eceived. available and you will have to agree that the Sony ICF 2001 is the AUTOMATIC SCANNING of the above banas. Continuous best value in shortwave receivers today: scannlng of any des~redp ortion of the band IS achieved by DUAL PLL SYNTHESIZER CIRCUITRY covers entire 150 KHz to setting the "L," and "L2" keys to define the range to be scanned. 29.999 MHz band. PLL, circu~th as 100 KHz step while PLL2 The scanner can stop automatically on strong signals, or it can handles 1 KHz step. both of which are controlled by separate be done manually. MANUAL SEARCH is sim~lart o the manual quartz crystal oscillators for preclse, no-drift tunlng. DUAL CON- scan mode and is useful for qu~cks ~gnals earching. The "UP" VERSION SUPERHETERODYNE circu~trya ssures superior AM and "DOWN" keys let the tuner search for you. The "FAST" key reception and htgh image rejection characteristics. The 10 7 MHz increases the search rate for faster signal detection. MEMORY IF of the FM band is ut~l~zeasd the2nd IF of the AM band. A new PRESETS. SIX memory keys hold desired stations for Instant type of crystal f~lterm ade especially for this purpose realizes one-key tuning in any mode (AM. SSBICW, and FM), and also. the clearer reception than commonly used ceramic filters. ALL FET "L," and "L2" keys can give you two more memory slots when FRONT END for high sensitivity and interference rejection. Inter- not used for scanning. OTHER FEATURES: Local, normal, DX modulation, cross modulation, and spurious interference are ef. sensitivity selector for AM; SSBlCW compensator; 90 min. sleep fectively rejected. FET RF AMP contributes to superior image re. timer; AM Ant. Adjust. jection, high sensit~vity,a nd good signal to noise ratio. Both strong and weak stations are received with minimal distortion. SPECIFICATIONS CIRCUIT SYSTEM: Fm Superheterodyne; AM Dual conversion superheterodyne. SIGNAL CIRCUITRY: 4 IC's. 11 FET's, 23 EXTENDED SPECTRUM CONTINUOUS TUNING Transistors, 16 Diodes. AUXILIARY CIRCUITRY: 5 IC's, 1 LSI. 5 LED'S, 25 Transistors. 9 D~odes.F REQUENCY RANGE: FM 76.108 MHz; AM 150.29,999 KHz. INTERMEDIATE FREQUENCY: FM 10.7 MHz.; AM 1st 66.35 MHz., 2nd 10 7 MHz. ANTENNAS: FM telescop~c,e xt. ant. term~nal;A M telescop~cb, u~lt-infe rr~teb ar, ext. ant. terminal. POWER: 4.5 VDCll2O VAC DIMENSIONS: 12th (W) X 2% (H) X 6% (n).W EIGHT: 3 Ib. 15 or. (1.8 kg) 2 October 1981 Tell 'em you saw it in HAM RADIO1 magazine incorporating ~lume1 4, number 10 T. H. Tenney. Jr.. WlNLB publisher and editor-in-chief Alfred Wilson, WGNIF 10 trapping the mysteries of trapped antennas editorial staff Gary E. O'Neil, N3GO Manin Hanft. WBlCHO product~on& ,tor 18 using simulated carbon JOSRP~J . Schroedar. WJUV Leonard H Anderson microphones with Amateur assoctate edttors W.E. Scarborough. Jr . KAIDXO transmitters graph!= product#onm anager Frank S. Reid, W9MKV Irene Holllngsw~nh editorial assostant . w E Scarborough. JI KAIDXO 24 junk-box portable antenna John J. Malarkey, W3SMT publishing staff J CralgClark. Jr.. NlACH 28 operation upgrade: asmtant publisher and advenlslng manager Susan Shorrock clrculatlon manager Robert Shrader, WGBNB ham radio magazine 42 ham radio techniques is publoshed monthly by GreenCvotlmlem. Nuenw~ cHaatimonpssT heicreh n0o30lo9g8y-,0 4In9c8 Bill Orr, W6SAI Telephone, 603-878-1441 50 avoiding built-in digital- subscription rates circuit problems, part two United States: one year. $16 50 two years. $28.50:t hree years. $38 50 Penn Clower, WlB G Carl ade and other countries lvia Surface Ma811 one year, 821.50; two years. $40 W three years. 957.M) 56 ICOM 701 owners' report Europe, Japan. Afrlca lvia Air Forwarding Service] one year. $28 W Martin Hanh, WBlCHO All subscription orders payable in Unitad States funds, please 62 SWR meter for the foreign subscription agents high-frequency bands Foreign subscription asents are Ken Powell, WBGAFT listed on page TI 66 locating geostationary M ~cop,es ~ ~ ~ , ~ ~ are avallable from satellites Un~versityM icrofilms. International Ann Arbor. Mlchigan 48106 Walter E. Pfiester, Jr., W2TQK Order publicallon number 3076 Cass~ltta~pe s of 981ected artlcles from ham rod10 are avallable to the blind and physically handicapped from Recorded Perladicals 919 Walnut Street. 8th Floor Philadelphia. Pennsylvania 19107 94 advertisers index 6 letters Copyright 1581 by CammunicationsTechnology.I nc 46 DX forecaster 81 new PI cts Title registered at U.S. Patent Office 77 flea market 4 observ n and second-class postage paid at Greenv~lle.N H 03098-M98 91 ham calendar opinio~ and at &t,onal mailtng oftices 72 ham mart 9 presstc ISSN 0148 5~ ,stmastar sand Form 3679 to hmr ndlo 74 ham notes 94 reader rice Greanvills, N.W Hampshlrs 0~0ls-04~ October 1981 9 Observation & Opinion From time to time I tune across the Novice bands just to see what's going on and to learn how the beginners are developing their operating skills. I sometimes fire up my rig and work a few Novices. In most cases the Novices appreciate a more experienced CW operator invading their territory, espe- cially if the latter is patient and understanding. I recommend that all experienced CW operators take the time to work a few Novices. It's a welcome change from fighting the pile-ups and gives a sense of accomplishment, especially if you've helped a Novice improve his code proficiency and operating procedures. Listening on the Novice frequencies can be an interesting experience. The Novice portion of the 40-meter band is a good example. Here you'll find some operators who are pretty good - their send- ing, although not fast, is clear and clean, and their operating techniques are on a par with those of many General-class operators. A few have electronic keyers or keyboards, but most plod along with a straight key. At the other end of the scale, you'll find Novices who just can't seem to break bad operating habits. This is where an experienced CW operator can really help, but it takes a lot of patience and, above all, tact. Many Novices don't know what to do after they've called CQ. The over evening I heard a station sending CQ continuously at a rapid rate for three minutes, followed by his call sign, which was sent only once. After a pause of a few seconds, the CQing started again. This was repeated for another - three or four minutes still no response. Then I tuned up the band a few kilohertz, and there was - another Novice calling CQ. The same pattern was again repeated no response. All in all, I heard perhaps ten stations across the Novice portion of the band calling CQ. One wonders if they had their receivers turned on. Then I tuned back to the first station and there he was, still at it. When he signed this time I gave - him a call, being particularly careful to match my sending speed to his. I signed over nothing. Then, "QRZ? QRZ?" I sent my call again at his speed. Again, "QRZ?" This went on for a few min- utes, then I reduced speed to about half and the Novice finally answered. We had a pleasant contact for a while, with the Novice sending at a considerably slower rate than before, complete with all the punctuation marks. I mentioned earlier that many Novices don't know what to do after calling CQ. I find that many Novices, after returning to the receive mode, don't tune around their transmitting frequency. Appar- ently they expect the replying station to be exactly on their transmitting frequency, which is unlikely in many cases. If the Novice is using a sharp CW filter in the receiver, the answering signal could be outside the receiver i-f passband and will never be heard. The best answer to the CQ problem is don't. Old-timers will recall a filler cartoon that used to run in QST years ago. It showed a mama cat walking along the top of a fence, followed by three kittens. The caption was, "If you wanna get results, you gotta make calls!" Not only did it mean CQ calls but also calls to other stations. Another recollection of bygone days is the series of pieces in QST by T.O.M. (The Old Man). T.O.M. loved to write about "Rotten Radio." His poignant prose was directed to everything from rotten spark sets to rotten operating. I think we could use more of T.O.M.'s scathing criticism. Al- though he wrote in a humorous vein, there was a lot of truth in his observations. I'll bet if T.O.M. were alive today, he would endorse my sentiments about the operating practices of some of our Nov- ices. I feel it's the responsibility of the higher-class operators to give a little of themselves to assist those Novices that need help. Alf Wilson, WGNIF editor 4 October 1981 filter design I Radio applications than is table 1). ticle if they send me a stamped, self- For example, on page 59 of his arti- addressed envelope. Dear HR: cle, Mr. Fowler states he uses To further demonstrate how stan- I am writing to tell you that I en- "seven-pole LC lowpass filters with dard-value capacitors can simplify fil- joyed reading the "Rf Power Meter" cutoffs at 5.8, 9.6, 15.7, 23.1, and ter design and construction, I have article by Ralph Fowler, NGYC, that 30.4 MHz" to attenuate the harmonic made minor modifications to Mr. appeared in the June issue. I was par- amplitudes of his signal generator. Fowler's 5.3-MHz Butterworth band- ticularly interested in Mr. Fowler's These designs can be conveniently pass filter (fig. 9, page 61 of his arti- discussion of the directional bridge selected from my table 2 and only cle). The Butterworth design was and its associated accessories. I standard-value capacitors are need- modified into a Chebyshev design noted that several of Mr. Fowler's ac- ed. Also, all of the messy calculations that is easier to construct, and the cessories were lowpass and bandpass are eliminated. For the previously passband and stopband performance filters, and he referred the reader to listed cutoff frequencies used by Mr. of the two designs is very similar (see the ARRL Handbook for lowpass filter Fowler, I suggest Filter Designs #207, my fig. 1 of bandpass filter re- construction information. In my opin- 232, 138, 162, and 173, respectively. sponses). (The Chebyshev design ion, there are more useful references These designs have reflection coeffi- was based on my tabulation of pre- than the ARRL Handbook for the de- cients of less than 9.2 percent, and calculated five-element lowpass fil- sign of the seven-pole LC lowpass fil- they should perform satisfactorily in ters that was published in June, 1978 ters used by Mr. Fowler, and I wish to this application. I will be happy to - see reference 6.) Note that the in- bring these references to the atten- provide anyone with a copy of my ar- ductor values of the two different de- tion of Mr. Fowler and the readers of ham radio. fKvo Since 1972, 1 have had many arti- EUTTERWOR cles published on passive LC filter de- (N6VC) sign (references 1 through 8) in which tables of pre-calculated designs re- 500hnn c1 C1 Cs Soohma 3 quired only standard-value capacitors 8 10 to simplify construction. The most re- nmdpw tinsf .sbsnuw~d homm ~ S S 5 cent articles on this design aid was lamb .IOw for mmPan.nt valun). so 3 Flrrna~.lorb andpsu 1f111. &suns by NLVC and WSNPN. published in the January 7, 1981, .WE Fc C1.5 -4 U 11.5 Ul L3 issue of EON. I recommend this last Bultrsvcp . E-W Wnr) ipfl CF) ipFJ im) (PW (PW 20 2 reference to Mr. Fowler and your wCohrothb yekr 5.3 ism m wm ar rao ar4 3 nc I LO* 1.16 5.u 2mo n woo asie 11.5 aiw 10 readers for the expeditious design Nok: TD. WJNPN Chsbphs. EPF d..bn ha. bwn and construction of the seven-ele- 0pdknh.d M uro nly .Un&rbrahn CaPSCiion ! ! ! 1 ! !o ment lowpass filters mentioned in the article. (Table 2 of the reference is fig. 1. Calculated bandpass filter responsesbasedonan probably more useful for Amateur inductor Qof 100 at 5.3 MHz. 6 October 1981 signs are very similar, and therefore the inductors of the Chebyshev de- sign should be just as feasible to ob- tain as the Butterworth designs. If the bandwidth of the filter is made too small, the ratio of inductance values (L2 to L1,5) will become too large, Join him in the incredible world of electronics with NRI's all-new thus making it difficult to get good in- . training in the career of the future.. Electronic Design Technology. ductor Q and proper filter perform- a It's an electronic world we live in. And the indicators. It handles almost any circuit you can ance. The filter bandwidth selected designers of electronic circuits, controls, and design.. .linear and digital integrated circuits as by Mr. Fowler seems reasonable from systemsare the people who are shaping it. Take well as discrete components such as transistors your place in this exclusive company with this and diodes. a construction and performance exciting new training from NRI. Analysis and design work is speeded viewpoint. Capacitor values C2 are You can learn Electronic Design with the Texas InstrumentsTI-30scientific Technology at home. in our spare time. calculator. This engineer's instrument similar 470 pF compared with 75 pF) without quitting your jox, tying up your includes full trigonometric functions. but C1,5 and C3 are quite different. evenings at night school, or wasting gas logarithms. square root. squares, traveling to classes. Because NRI powers, rnemoy, and more. All this fine This difference is a consequence of comes to you, makes you a class / equipment is part of your training. yours changing the Butterworth design into of one with a complete, effec- to keep and use in your work. tive, low-cost learning pro- NRI Fast-Track a Chebyshev design. Mr. Fowler's B ram designed exclusively Training center frequency of 5.3 MHz was or home study. You get , This is the uniaue NRI slightly increased to 5.42 MHz to iitt aallll ......aa tt yyoouurr lesson concept that convenience. simplifies and speeds make C2,4 come out to a standard Hands-on learning. From the capacitor value 175). Training ve y basics toad- NRI trains vanced. state-of- Mr. Fowler was correct in his con- ;ou for action. the-art electronics. cluding sentence that "improvements ou get real-life each lesson is espe- experience that cially prepared for doubtless can be made," and this I builds priceless individualized in- have attempted to demonstrate as far cy.oo- nuf iwdoe~ rnkcien..g o uki vneosw ledyc of lab practices and ject is covered fully and thorsotruugchtliyo,n b. uEta ecxh tsruanbe- - as the passive LC filter design aspect techniques. It's all built Into the NRI Design ous material is eliminated, language is clear and is concerned. I am grateful to Mr. Lab? a complete combination of equipment, to the point, organization is logical and effective. hardware. training, and reference materials. From Fundamentals of Electronic Circuits Fowler for taking the time and effort You'll design your own circuits from the very through Microprocessors. our lessons are to write his articles, and I thank ham beoinnina. ~rouressinqfr om basic passive net- designed with you in minx wGks thk"ghlkey circuits like supplies, No Exyrience Necessary radio for publishing them. I hope to amplifiers, osciilators, digital and logic circuits. You don t ave to be an engineer (or even read many more similar articles which phase-locked loops and more. You'll move a college student) to succeed. High school on to linear and digital integrated circuits, the will assist me and others in improving heart of modern electronic equipment. You'll graduates with some algebra handle it without any trouble. We start you at the beginning, let our technical expertise. prototype your designs and verify operation. you advance just as quickly as ou're ready. We learning professional test and measurement even include the NRI Math ~elesheMr odule to procedures as you progress. help you brush up on your math and teach you references Professional Equipment Included any new concepts you may need. All the way, you work with professional- 1. E. Wetherhold, "Design Your Own Filters By Com- qualit instruments like the Beckman 6-func- Free Catawl yi puter," Electmnic Design. Vol. 20. No. 2, January20. tion, z6-range LCD digital multimeter. It gives No Salesman Call 1972. vou fast. accurate measurements of voltages, Our free. 100-pagec ataloy gives you all the 2. E. Wetherhold, "Pick A Filter From This Chart," Uectronic Design, Vol. 20, No. 24, November 23. 1972. 3. E. Wetherhold, "Low-Pass Filters For Amateur Radio Transmitters." OST, December, 1979. Ave., Washington, DC 20016. 4. E. Wetherhold, "Chebyshev Filters Using Stan- 1111.1111- 1 dard-Value Capacitors," RF Design, Vol. 3, NO. 2, NRI Schools Please check for one free catalog only. I February, 1980. McGraw-Hill Continuing Electronics Design Technology 5. E. Wetherhold, "Design 7-Element Low-Pass Fil- Color TV Audio. and Video I ters Using Standard-Value Capacitors," EDN. Vol. System Servicing Washington D C.2 0016 Computer Electronics including I 26, No. 1, January 7,1981. Microcomputers 6. E. Wetherhold, "Passive LC Filter Design (Part 1). 0D igital Electronics I Home Study Course 69/51." Measurements & Con- CLiocmenmseusn icMatoiobnilse ElCecBtr oAniicrcsr aFftC CM arine I W7. E,.a nWde MtheedrihcoalldU, e"cLtorownpiacsss, b Cohthe bJyusnhee, v1 9F7il8te. rs Use II NO SALESMAN WILL CALL. 0 BSmasaicll EElnecgtirnoen Sicesrv icing I Standard-Value Capacitors," Engineer's notebook, I 0 AApuptolimanocteiv See Srevrivciicnign g I 8p.a gEe. 1W6e0t.h Eelerhcotmldn. ic"7s-, EJluenmee 1n9t . C19h8e0b.y shev Filters for I (Please Print) 0 AAiur tCo oAnird Citioonndinitgio. Hnienagr ing. Refrigeration. ( Name &Solar Technology I TEMPEST Testing," ITEM. 1981, published by R b B 1 Building Construction Enterprises, Plymouth Meeting, Pennsylvania. I Street I Ed Wetherhold, W3NON ( City/State/Zip aGpI pbrioll.v ed under I ) Accredited by the Accrediting Commission of the National Home I Study Councll 20101 L1lII~m-mmIImIIII-l-ll-lI-J the 440 band with style! The new extra cost, and the ST-71T8s op- ST-7/T synthesizes the entire band tional synthesized subtone en- in 5 kHz steps, works both up and coder is controlled by the radio's down repeater splits and does it front panel switch. all right from your hand, with ver- satile power options of 3 watts, 1 All the regular SANTEC acces- watt or even 50 milliwatts (all sories used with your HT-1200 fit nominal), to reach out to where the ST-7/T as well, meaning that you want. The high power mode you can enjoy both bands fully of 3 watts radiates on 440 like 5 with a smaller cash investment. watts on 2 meters . . . and that's a Grab the new SANTEC ST-7/T and handfull! join the fun on 440 MHz. See your SANTEC Dealer for delivery Tones? This- one has them . .. tones details. - - and n The 16 button tone - a - .. SANTEC'S popular HT-1200 is the inco parable 2 meter leader. This little rig is hand- ing over quality, power and features that you'd expect from something nearer the size of a bread box. WTEC packs a 2 meter ham shack into the palm of your hand! You can carry scan, search, 10 memories and fully synthesized key pad control around with you and still get out with a big 3.5 watts (nominal). Compare them apples to anything you want, and settle for nothing less. WNTEC radios exceed FCC regulatrons limiting spurlous emissions. _ rlllllml----m---------- 1 I E1!nXc)Oo mAvmr.o Iinwc .G .I...... *,,.,, ,,,,. ,,.". I 1 h"'. AOO W,<F,\ ! J I I - n; 75074 k,:....,m$w rrc rwm I I I I -- -- -- I I CAU I Both the SANTEC ST-7/T and the SANTEC HT-1200 I I are certified under FCC Part IS. 1 - - I A W S 61 1981, Encomm, Inc. I I Phone2 (020104 )A 4v2e3n-0u0e2 G4. Suite I8N0T0L, TPLlaXn o2,0 T3e9x2as0 7E5N0C74O M UR 1 cnv - - --- STATE ZIP -=--a I L-m-m YUUHAYILnDAWWCITEOFTHDFOM. 7. . - 9 =-- *(IC ----x