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Internet Message Format | 1994-11-27 | 50.0 KB

Date: Tue, 10 May 94 14:14:54 HST From: Jeffrey Herman <jherman@uhunix.uhcc.Hawaii.Edu> To: Bruce Walker <bruce@Think.COM> Subject: Re: QRP Projects In-Reply-To: Your message of Tue, 10 May 94 19:47:26 EDT Here you go, Bruce - and feel free to edit them as necessary. Thanks again! Jeff ***************************************************************** Subject: Projects 1 - 4 Subject: PROJECT 1: 40M QRP XMTR Hi Gang, Here is the first of many very SIMPLE QRP transmitters. I make no claims to their performance! In the next few weeks I'll give you xmtrs for 80, 40, 20, and 2 meters; most requiring 3 or less transistors. The circuits come from 2 out-of-print ham projects books (c. 1968) so I will assume there will be no copyright problems. Project 1 is a simple 40 meter xmtr; it should only take 15 minutes to build it (if you've got the parts). I wasn't able to draw the symbol for each part on this terminal, so I put the part number in it's place. Hope you don't mind... Note that the case of Q1 should be grounded. Here's the text for this project, taken from "101 EASY HAM RADIO PROJECTS" by Robert M. Brown, k2zsq/w9hbf and Tom Kneital, k2aes/wb2aai: "Want to really shake up your next contact? Just tell him you are using this one-transistor CW rig! Most Novices and other hams shy away from these little gems thinking they are hopelessly underpowered. Not so! More than 50 contacts - all located over 75 miles distant - have been logged with this rig connected to the backyard longwire! "Construction is quite simple and, in fact, there is not much to say about it. Reason: there isn't very little that can go wrong! "L1 should be adjusted for maximum deflection on an FSM as the key is depressed. Crystal should be a fundamental frequency type for 40-meter operation." Parts list: C1 68 pF capacitor C2 .015 uF capacitor C3 10 pF capacitor L1 25 turns of No. 26 enameled wire wound on a 3/8 in. slug- tuned form (National XR-91 or equiv.) M1 4.5 volt battery M2 40-meter fundamental freq. crystal Q1 GE-9 transistor R1 91K resistor --------M2--------*----------*-----------*----------C3-----------ANT. | | | | | | | | | C C1 L1 *--------------B Q1 | | | E | | | | ----*------------ | | | | R1 GND | | | C2 | | | | | GND | | | -----------------------------*---------_M1+---KEY-------GND That's it! Note that GND = ground (and note the polarity of M1). For Q1, I've labelled its leads B = base, C = collector, E = emitter. * indicates a junction of 3 or more leads. Remember, no flames if it doesn't work; I'm just the messanger! Project 2 will be an 80M VFO QRP xmtr; stay tuned. (Oh yes, there IS a 2M xmtr on the way). Jeff, NH6IL Jeffrey Herman, University of Hawaii Mathematics, jherman@Hawaii.Edu ****************************************************************************** Subject: Project 2 - 20 meter QRP CW xmtr Here's the second QRP project taken from 101 EASY HAM RADIO PROJECTS, by Robert Brown and Tom Kneitel; again, since the book is out of print, I assume there will be no copyright problems... This project is a simple 20 meter CW xmtr with output about 100 mw (?). Here are the authors' comments: "If you have always wanted to try low-power on 20 meters, here is an excellent method for joining the growing ranks of flea-power addicts - and doing it inexpensively. This circuit is capable of world-wide QSO's, given the right conditions and assuming QRM is not present. "The transmitter uses a pair of GE-1 universal replacement transistors in a unique circuit configuration a great more sophisticated than you would normally expect for an under-one-watt rig. Crystal can be a fundamental 14-mHz type. "L1 should be adjusted for sure-fire oscillation every time the key is depressed. C4 is simply adjusted for maximum output on the FSM." PARTS LIST: C!, C2 .02 uF capacitors C3, C5 .002 uF capacitors C4 51 pF variable capacitor L1 38 turns of No. 22 enameled wire on a 1/2 in. diameter slug-tuned form L2 8 turns of No. 22 enameled wire wound over cold end of L1 L3 Coil, 17 turns of Air Dux 616T (or equiv.) tapped 5 1/2 turns from cold end L4, L5 2.5 mH rf choke (National R-100 or equiv.) M1 1.5 volt dry cell M2 6 volt battery M3 14 mHz crystal Q1, Q2 GE-1 transistors R1 180 ohm resistor R2 1.1 megohm resistor As before, rather than trying to `draw' the symbol for each component, I've just inserted the part number. Oh, note the polarities of the batteries M1 and M2. GND = ground, ANT = antenna, E = emittor, ANT C = collector, B = base, KEY = well, this is a CW rig.... | *---- | | --------*-------- ------------- ----*-----C5--------L3 | | | | | | | | | C4 L4 M3 E-Q1-C | GND-E-Q2-C | | | | | | | | | GND GND | | B | B L5 * --- GND | | | | | | | | | | | | | ---------------------- | R2 | | | | | | R1 L1 L2 | | GND | | | *---------------* | | | | | | GND GND | | | *----C2--- C3 | | | | | | | | ---KEY--*--+M1--GND ----M2+--* GND | | | | C1 GND | | GND Note that the collector of Q1 `jumps' over the hot end of L2; this is the only jump. * = a junction of 3 or more leads. .... .- ...- . ..-. ..- -. ! Jeff, NH6IL Jeffrey Herman, University of Hawaii Mathematics, jherman@Hawaii.Edu *********************************************************************** Subject: Project 3: 80M xmtr with VFO Hi Gang: An opinion from someone at our law school is not to worry about any copyright violations; email me for full details. This week we have an 80 meter 1/10 watt output xmtr with a VFO! Not too many of us still have a drawer full of xtals (gave all my away when I sold my DX-60). Construction is pretty straightforward. C5 is the VFO-frequency- adjust control, while C4 acts as a preset calibrator. Output is governed by setting of C9. It is most important to shield the VFO section entirely (including Q1); this will prevent hand capacitance from pulling you off frequency. PARTS LIST C1 .002 uF cap C2 500 pF cap C3 1000 pF cap C4 15 pF variable cap C5 51 pF variable cap C6 100 pF cap C7, C8 .015 uF cap C9 76 pF variable cap C10 .0015 uF cap L1 57 turns of Air Dux 832 (or equiv.) L2 35 turns of B&W 3016 (or equiv.) L3, L4 2.5 mH rf choke (National R-100 or equiv.) M1 0-15 dc milliammeter M2 12 volt battery Q1 2N744 transistor Q2 2N852 transistor R1 120K resistor R2 100K resistor R3 2.2K resistor R4 2.4K resistor -------------------------------------------- ANT | | | | | | | | | *----------R3-----------L3 | C10 | | | | | | | | R1 | | --B-Q2-C--------* | | | | | | | | | | E | *-------*-------B-Q1-C---* | | | | | | | | | | | -----*---- | | E | | | GND | | | | | | | | | | R2 C1 | *------- |--------(----- | | | | | | | | | C9 L2 | | | | | | | | | GND GND | C2 L1 | | | | | | | | | ----*----- | | | | | | *-----*------(-------C6----------* | | | | | | | M1 | | | | | | R4 C3 *------ L4 ----------*----| | | | | | | | | | | | | | + GND GND C5 C4 GND C8 M2 | | | | | | | | GND GND -----KEY------*----- | | | | *-----C7------- | | GND Notes: * indicates a junction of 3 leads. ( indicates a jump. B = base, C = collector, E = emitter. KEY = manual telegraph key. GND = ground. Coming attractions: 1 transistor 160 meter xmtr; 3 transistor 2 meter xmtr; 15 meter xmtr; other goodies, too! .... ...- ..-. ..- -. Jeff NH6IL . . Jeffrey Herman, University of Hawaii Mathematics, jherman@hawaii.edu ************************************************************************** Subject: Project 4: 160 meter phone xmtr Gang: Here's the next project: a 160M phone xmtr; sorry it's AM but these are OLD project books! Just the simplicity of it should make it fun to build and play with. It's VFO tuned by adjusting the slug of L1. In fact you can use this on 75 meters (and there IS some AM activity on 75) just by changing the final L/C network accordingly. Note that as various antennas are tried, the frequency will change markedly, necessitating readjustment of the L1 slug. The microphone should be a low-impedance crystal type. Parts list ---------- C1, C2 4 uF, 15 VDC electrolytic caps C3 100 pF C4 .015 uF C5 180 pF L1 Vari-loopstick (WRL 10M162 or equiv.) M1 9 volt battery Q1, Q2, Q3 GE-2 transistors R1 10K resistor R2 750K R3, R4 5.1K R5 200K R6 75K S1 SPST switch ANT | | MIC---+C1---*---*---B-Q1-C---*---C2+---*---*---B-Q2-C---*---C3---*---*--- | | | | | | | | | | | | | | | E | | | E | | | | | | | | | | | | | | | | | R1 R2 | R3 R4 R5 | --E-Q3-C-- | L1 | | | | | | | | | C5 | | | GND | GND | GND | B | GND | | | | | | | ----------*----------*---------------*----------- | GND | *--- | | | | | | ----S1---+M1---GND R6 C4 | | | | *---- | | GND Since the xmit frequency can change as you change antennas, I bet a strong wind blowing against a longwire antenna will cause a little `swing' in frequency... This circuit was taken from Brown and Kneital's 101 EASY HAM RADIO PROJECTS. Next up is a one-transistor 15M CW xmtr; stay tuned. Jeff, NH6IL Jeffrey Herman, University of Hawaii Mathematics, jherman@hawaii.edu Subject: Project 5: 15 meter CW xmtr Here's a one transistor flea-power CW xmtr for 15 meters (I'll provide a 2 transistor 1 watt xmtr as the next project for those of you who want to run high power on 15M...) To tune-up the xmtr, just peak C2 for maximum signal on your receiver's S meter. Parts list: Q1 2N373 transistor C1,5 4700 pF capacitor C2 3-30 pF trimmer C3 30 mF C4 1000 pF R1 10K resistor R2,3 510 ohm R4 50K B1 9 VDC battery L1 17 turns B&W 3007, tapped 8 turns from C5 end X1 21 mHz fundamental 3rd overtone crystal ----X1----*------*------ | | | | | C | | | | C2 L1----C1-----ANT -----------*-------B-Q1 | | | | | | | | | E | | | | | | | ---------|-----------|--*-C3+-*-*-- | | | | | | | | | | | | | | | | | | | | R1 R2 C4 R3 | | | | | | | | | | | | | | | | | | | | ---*-----*----*---*--C5--* | | | | | | | ------R4--------*--------------------- | | | | -------------------------*----KEY----B1+----GND Note the battery's polarity. Recall that * indicates a junction of 3 or more wires; there are 2 jumps - one from R4 and the other from R1. Sorry, only straight keys can be used in this xmtr... Credit goes to Bert Simon, W2UUN, and his book, 104 HAM RADIO PROJECTS. Jeff NH6IL Jeffrey Herman, University of Hawaii Mathematics, jherman@Hawaii.Edu ************************************************************************ Subject: Project 6: 80M QRP `colorburst' CW xmtr Keywords: cheap, cw, fun Gang, In preparation for tomorrow's 80M QRP Colorburst Contest, here's a quick 80M xmtr you can throw together in 5 minutes; the 3579 kHz xtal comes, naturally, from the colorburst oscillator board in your color TV (if you've got a junked TV, or if you think TV only contains junk, yank the xtal out). The rf output is not much - about 25 mw. Tuneup is simple: just bring a field strength meter into vicinity of L1/L2 and tune L1 for peak deflection of the meter. If you really want to get fancy, you can substitute a 100 pF variable for C3 and optimize a bit further; this involves a bit of experi- mentation to determine a `norm' setting for L1/L2. After this has been established, all further tuning can be accomplished with C3. Parts List: C1 .047 mF capacitor C2 .0015 mF C3 100 pF L1 18 turns of No.30 wire closewound on 3/8 in. diameter slug-tuned form L2 5 turns of No. 30 closewound around middle of L1. Experiment with posi- tion of this coil over L1; in some circuits performance will be increased by moving L2 towards cold end of L1. Once exact position has been determined (with ant. hooked in and FSM for monitoring), glue in place. L3 2.5 mH rf choke (National R-100 or equiv.) M1 3 volt battery M2 6 volt battery M3 80 meter xtal Q1 HEP-2 transistor R1 330 ohm resistor R2 27K resistor S1 spst switch ---------M3---------- ANT | | | | | | *------E-Q1-C-------*------------*------- -------------- | B | | | | | | | | L3 *-------- C3 L1 L2 | | | | | | | | | | | | R1 R2 C1 *------- GND | | | | | | | | | GND GND | | | | *----------KEY------M2+----GND ----------S1---M1+---GND | | C2 | | GND Note the polarity of M1 and M2. Hope to hear some of you on the `official colorburst frequency' of 3579 kHz! Jeff NH6IL Jeffrey Herman, University of Hawaii Mathematics, jherman@Hawaii.Edu ********************************************************************* Subject: Project 7: 15 watts on 80 and 40* Keywords: cheap, cw, fun * If you are reading this on the rec.radio..homebrew newsgroup feel free to run the full 15 watts. BUT, if you are reading this on the QRP mailgroup you can only use this xmtr in the standby mode (a few milliwatts)(no fair cheating now...). Here's the most sophisticated xmtr project so far: 15 watts output on 40 and 80 meters. There is a standby mode which keeps the oscillator ticking but cuts out the PA transistors - use this for zero-beating your rcvr to the xmtr output frequency (uh, I guess this really isn't necessary with today's receivers... This IS an old book). The book is 104 HAM RADIO PROJECTS FOR NOVICE AND TECHNICIAN, by Burt Simon, 1968. Burt says: "RFC1 should be a low resistance; use a 1/4 inch loopstick and at least 20 turns of #28 wire or larger. No component values are critical except for the amplifier coils. The NE-2 bulb should be mounted flat against the chassis near the #49 bulb with both leads connected to the antenna lead and only stray capacitance to ground. Also be sure to use a fundamental- frequency crystal. The oscillator transistor does not need a heat sink, although you'll need a Wakefield #NF207 on the buffer transistor. "Tuning: Only final amplifier adjustments are necessary. Tune always for maximum output, NOT MINIMUM PA CURRENT. Normal tuning of C9 and C10 should bring about a satisfactory bulb brilliance. If antennas are under 30 feet (or 1/2 wave), output capacitance will be much less and tuning capacitance more; the #49 bulb will show less current, but the neon bulb will ignite showing high voltage feed. In general, tune for maximum bulb brilliance regardless of load." Parts List: ----------- Q1,2 2N697 transistor; use Wakefield #NF207 heat sink on Q2 Q3,4 PADT50 C1,4,12 330 pF capacitor C2 .068 mF C3,5 .01 mF C6,8 .22 mF electrolytic, 50V C7 820 pF C9,10 365 pF variable C11 330 pF R1 27K resistor R2 3.3K R3 330 ohms R4 10K R5 100 ohms 2W R6 1.5 ohms 2W -------------------------------->12-28VDC | | | ------------------->12VDC (for zero beating) | | | R * ------------*------------*----*--- SW1A | | | |T * | | | | | R1 RFC1 C5 | *----*----*----*---- | | | | | | | | | | | GND | | | | | | *---X1------*---C4---- | C6 RFC3 C8 R6 I3 | | | | | | | | | | | *-B-Q2-C-- | | *----*---* *--B-Q1-C---- | E GND | | | | E R4 | | E E | | | *-----C7-----* Q3-C--C-Q4 *-C1-*---- | | | B B | | | | R5 | | | R2 R3 C3 | | *----*--------- ANT | | | ----* | | | | | | | ------>RCVR ANT | *----*---*-----RFC2------- | | ----I1----* | | | |R | | | | | * SW1B | | C2 ----KEY---GND | -----*--L1--*--*--L2--*--*--L3--* | -----*T | | | | | | | | | | | | | GND RFC4 | C11 C10 | I2 | | | LOAD | | | C9 | | C12 | GND TUNE | GND | GND | | | GND | | 80*|*40 LO*|*HI | | SW2 * * SW3 | | | | GND GND Whew! Okay, note that the 40M terminal of SW2 is not connected to anything; neither is the HI terminal of SW3. As I written, C9 is the tuning and C10 is the loading capacitor. Jeff NH6IL ***************************************** Subject: Project 8: 1 1/2 watts on 80M CW Keywords: cheap, CW, fun Can you all stand one more 80M xmtr? (Do you get the feeling that I'm trying to push for more 80M activity? I really love that band!) The book is 104 HAM RADIO PROJECTS FOR NOVICE AND TECHNECIAN by Burt Simon. Burt says: "This rig has provided many hours of fun for the authors in the 80M novice band, where regular 800 mile DX has been nothing out of the ordinary. In fact one contact was made with a W6 in Los Angeles from our Long Island,NY QTH. "Tuning is conventional. Transistors should be loaded to about 50ma in the bottom of the dip if you're pumping in the full 30 volts. With C6 about half meshed, L1 should resonate at the low end of the 80M band. (You can check this with your GDO)." Parts List Q1, Q2 2N269 transistor C1, C2 150 pF capacitor C3, C4 300 pF C5 .01 mF C6 200 pF variable C7 50 pF R1, R2 470K resistor R3, R4 2K R5 200 ohms B1 30 VDC battery L1 30 turns, center-tapped, on 1 inch form, with 4 turn link into center for output RFC1,2 2.5 mH RF choke (National R-100) X1 80 meter fundamental crystal M1 0-100 DC milliammeter ANT | --------*--------*--------*--------B-Q1-C-------- | | | | | E | C7 | | | C1 | | | | R1 R3 | RFC1 *--------- | | | | C3 | | | ------- | | | | | | | | X1 *----- *--------*----------*---GND C6 ) | | | | | | | | ) L1 ( | | | | C4 | | ----) ( | R2 | R4 | RFC2 | | ) | | | | | C2 | | | | | | | | | | E | | | GND --------*----)---*--------*--------B-Q1-C-------*----)---- | | | | --+B1---M1---*--------------------------------R5-----*-----C5-----GND | | | ----KEY----GND Note the polarity of B1; there are two `jumps': between R2 and R4, and over the `hot' end of L1. 1 1/2 watts should be real fun - not quite the challenge as the 25 mw xmtr. Okay, no more 80M xmtrs! I promised I'd post a 2M xmtr - I have two - neither are FM, though. I'll post them next and let you folks figure out how to FM them; shouldn't be hard at all. (Probably only the r.r.a.homebrew folks will be interested in them, but you QRP mailgroup folks might have a use for them also.) Jeff NH6IL (ex: WA6QIJ) ************************************************************* Subject: Project 9: 2M CW transmitter Here's the first of two 2M xmtrs: this one is a 2-transistor CW rig and the other is a 3-transistor AM circuit which you can FMize yourself (of course the AM xmtr can be used for CW, too). Here's what Burt Simon in 104 HAM RADIO PROJECTS FOR NOVICE AND TECHNICIAN (1968) has to say: "Here's a dandy 2-meter CW rig that will astound the local gang. Using only 2 transistors and a 72 MHz third overtone crystal, you can practically carry the set around with you. It can be built into the tiniest of boxes and requires only a 9-volt battery to power it. At least one VHFer has worked 110 miles with this transmitter, and several (built as club projects) have been equipped with simple one-transistor modulators. "Construction is simple, although care must be taken to insure that all leads are as short as possible. L3 should have its iron-core slug removed. The RFCs are simple 1/2 watt resistors wound full of #36 enameled wire. To check their efficiency, use a grid dip meter to see if you're anywhere near 144 MHz. If they aren't, remove or add turns until the desired frequency (should correspond with your transmit frequency) is achieved. L1 should be neutralized by winding a full solenoid of #26 wire on a 1 meg, 1 watt resistor. Leaving only about 1/2-inch of lead, solder the choke to the crystal socket. It should resonant at your operating frequency. "Main thing is to get the crystal to oscillate. If you have trouble, adjust L2 and expand or compress the turns of L1 until you hear (using a 2-meter receiver) the oscillator harmonic. From here on in you can simply tune for maximum signal using a GDO, field strength meter, or receiver S meter." Parts List Q1, 2 2N1745 transistor C1, 2 .001 mF capacitor C3, 4 .01 mF C5 50 pF C6 12 mF, 5% R1 510 ohm resistor R2 30K R3 10K R4 100 ohms B1 9vdc battery L1 19 turns #24 enameled wire on 1 meg, 1 watt resistor L2 9 1/2 turns #24 enameled wire on 5/16 inch slug-tuned form L3 6 1/2 turns #24 enameled wire, spaced 1/6 inch on 5/16 inch slug- tuned form L4 1 3/4 turns #22 enameled wire on cold end of L3 RFC1,2,3 #36 enameled wire wound (and glued) on 1/2 watt resistor. Should check to approximately 145 MHz with GDO. If it doesn't, adjust number of turns. (Ohmite Z-144) X1 72 MHz 5th overtone crystal SW1 SPST switch ---L1--- | | | | ------------*--X1--*------------ | | | | *------------E-Q1-C------ C1 | B | | | | ) | R1 | L2 )------)------C6---*---E-Q2-C------- -----C5---ANT | | ^ ) | | B | ^ | | | | )------- | | ) | ( RFC1 | | ) RFC2 | L3) | (L4 | | ) | GND ) | ( | | | | | | GND -------*--R2-*--* R4 ------* | | | | | | | | GND | | | | | | | C2 R3 C3 | GND C4 RFC3 | | | | | | | | | | GND | GND GND GND | | -----------------------------------*---SW1--B1+--GND Notes: Observe good VHF wiring techniques (we can't be as sloppy here as we are down on the HF bands!) The positive pole of B1 goes to ground. I attempted to use arrows to indicate the adjustable coil forms. Nothing was said about the two taps coming off of L2 - you'll have to experiment as to their placement. C1 jumps over the other tap from L2. If any of you build this pup let the rest of us know how you got it to work.... (who in the world has even got 72 MHz xtals anymore?) Jeff NH6IL (ex WA6QIJ) ************************************************************************ Subject: Project 10: A BFO for your $40 SW rcvr It seems there are quite a few cheapie shortwave receivers out there that have everything (synthesizer tuning, digital readout, fairly good specs) but lack the all important BFO to copy SSB and CW. Well, let's remedy that problem right now. The heart of this project is a 455 kHz IF transformer: go to your closest junked broadcast radio receiver and steal one from there. If you are reading this on rec.radio.shortwave you may skip this paragraph; if you are reading this on rec.radio.amateur.homebrew or on the QRP mailgroup here's a neat idea: get one of these cheapie SW rcvrs and after installing this BFO you'll have a great companion to any of the simple transmitters I've been posting! Let's face it, xmtrs are easy to build, but rcvrs certainly require more care; for $40 you can pick up one of these synthesized digital readout pups and have a complete backpack transmitter-receiver pair. PARTS LIST Q1 2N544 transistor C1 15 pfd variable capacitor C2 .001 mfd C3,4 .01 mfd R1 7.5K resistor R2 5.1K B1 1.5 VDC battery T1 Miller #9-C2 IF transformer SW1 SPST switch ------------------------------------- ANT | | | | | | R1 | | | | | | | | *------*------B-Q1-C-----*----------)-------------*------C2-------- | | E | | | | | | | | | R2 | | C1 | *----- | | GND | | | ) | | | | | ) GND | GND | C ) -------O | | | ) ( | *-------------)----) ( N.C. | | | ) ( | | | ) -------O | | | ) --------------C3-------------)-------------*----- | | *-------SW1-----B1+----GND | C4 | GND Recall: Q1 is marked B=base, C=collector, E=emitter; the case of Q1 MUST be grounded; GND=ground; note the polarity of B1. Now, the unmarked capacitor, C, and its associated transformer, are inside the can of the IF transformer; if you remove the can you'll see where to make the connections. N.C. means not connected - while you have the can off you'll have to cut those leads. Also, screw the tuning screw slug all the way out. After you've put everything together set C1 about midway. Adjust the transformer slug until it resonates at 455 kHz, which can be accomplished using a receiver or GDO. AS you tune the slug (using the receiver) you should hear the heterodyne note of the BFO lowering in pitch until it eventually zero-beats. Stop tuning at this point. The BFO antenna can be any piece of hookup wire wrapped around the antenna wire near (or even inside of) the receiver. Whenever you want to copy CW or SSB, merely flick on SW1. Jeff NH6IL Here's a two transistor 15 meter xmtr gotten from Bert Simon's book 104 HAM RADIO PROJECTS (1968). Bert says: "As any novice knows, 15 meters is where the action is, at least if you're a DX addict. So, imagine the fun in telling your 1000-mile contact that you're running less than 1-watt into a 2-transistor rig. It is important that you use a miniature 5-prong coil form for L1. Follow the directions in the parts list to the letter. L2 is wound over the lower turns of L1, using the same coil form pin connections. As you can see in the schematic, the 40-meter crystal oscillator output is tripled to 15 meters. "Tuneup is simple. Depress the key (intermittently to avoid damaging Q1-Q2), noting the meter reading. It should be 5-8 ma. (If it isn't, adjust C1 until this range is reached). Switching to the other meter position (PA), adjust C1 for maximum. Using an output bulb (neon or #49) adjust C8 for minimum capacitance. Now tune C7 for a meter dip to about 4.5 ma. While dipping C7, tune C8 for maximum bulb brilliance." Parts List Q1 2N247 PNP transistor Q2 2N372 PNP C1,7 15 pf variable capacitor C2 10 pf variable C3,4,5,6 .001 mf C8 50 pf variable R1 10K resistor R2 180 ohms R3 3.6K R4 51K B1 12VDC battery L1 Use 5 prong miniature coil form; 15 turns #20 insulated wire, tapped at 3 3/4 turns from the bottom. Top of coil should be connected to pin 1 of the base, bottom to pin 2, tap to pin 3. L2 Wound over L1 in same manner to same connections as above; 15 turns #20 insulated wire with a 4 3/4 turn link. One side of link goes to pin 4. X1 7 MHz 3rd overtone crystal M1 0-10 DC milliammeter SW1 DPDT SW2 SPST -----X1-------*-----*-----*------ | | | | | | | | | |pin1 *---*----B-Q1-C C1 C2 ( | | E s | | L1(-----C5----*----B-Q2-C--*----- ---ANT | | | \ | | ( | s E | 1) (4 R1 | | | | | |pin2 | | | | ) L2 ( | | *--C3----*--*--* | R3 | | C7 ) ( | | | | | | | | | 2) (5 GND | | GND | | | | | | | | R2 | GND---*-----*-*----*-C6-* C8 | | | | | | ---KEY----GND---C4---*---------------------- | GND | | | | | | --------------*--- | | | | | | | | ---------------*-SW2-B1+--GND | | | | | | | | | o o o | | _ | | / | M1 | | OSC / PA | | + -------------R4-------------*------------o o o----- | /| | / |______________| SW1 Notes: Q1 and Q2 have a marking: (s) on the schematic which appears to be the case of the transistors - on both cases (s) goes to ground. The numbers next to L1 and L2 are the pin numbers of the coil form. The wiring for SW1: If 3 or more wires meet without the junction symbol * then there is a `jump' (no connection). The positive terminal of B1 goes to ground. The usual warning applies here as with the other 9 transmitters: these circuits are old - tighter emission standards are in effect now that weren't when these were first published; make sure you signal is `clean' by applying proper filtering if necessary. .... .- ...- . ..-. ..- -. Jeff NH6IL (ex: WA6QIJ) Jeffrey Herman, University of Hawaii Department of Mathematics jherman@hawaii.edu jeffrey@math.hawaii.edu Gang, Here's another 80M xmtr; this one's supposed to be capable of 1-2 watts. I got this out of a book called ``1000 Transistor Circuits'' or something like that. ----250pF----- | | GND-----*---100pF/V---* | ) L2 ) )----.002uF----*---ANT ------XTAL----*----*----75pF/V-------*---B-C---*----) | | | | | E | ) | | | ) | | | | 5Kohm | 250pF ) | GND | | | | | ) | | *--.001uF-- | *---B-C-------|----) *---B-C---- | | | | E | ) L1 | E | | *---- | | | | | | | GND | | 82K | -----*---.001uF--- | GND | | | ohm | | | RFC | 5Kohm | | *--KEY--GND | GND | | | 1N34 | | | GND | | diode | .001uF | | GND | | | | | | | GND | | ----* | | | | | -------------------*----------------*---------------*---+12VDC .001 + | uF 0-1 2uF | mA 50V GND | | GND GND The 3 transistors are 2N2270. Two capacitors show: /V - means variable. L1 is 30 turns on a B&W #3012 coil form, with a tap 10 turns from bottom. L2 is 18 turns on a B&W #3015 coil form, tapped 3 and 7 turns from bottom. Only numerical values were given for the capacitors so I've interpreted this as ``whole number values are in pF and decimal values are in uF'', except the 2uF 50V cap - that was specified. The 1N34 diode's symbol should be oriented: \ / \/ -------- | to meter Now yank that 3579 kHz crystal out of your color TV set and have fun! Jeff NH6IL Gang, If there was a contest to come up with a xmtr containing as few parts as possible, this would be the winner: 10 parts if you include the key, battery, and antenna! In the CODE/NO-CODE debate on r.r.a.policy some pro-coders will mention the simplicity of CW xmtrs as opposed to those of other modes; this circuit really drives that point home (that's why I'm posting this on .policy) On r.r.a.misc we've heard talk about how costly ham gear is today - all this rig will cost you is the effort to find an old color TV chassis - that's the parts source for all my QRP transmitters (and this is why I'm also posting this on .misc). Normally I post these xmtrs only on r.r.a.homebrew and on the QRP mailgroup; so if you've missed the first dozen xmtr circuits email me and I'll send them off to you. I built this for 80M only because I've got so many 3579 kHz crystals from old TV sets, but this can be used on any HF band - just choose L and C to resonant at the crystal frequency. For peace of mind you might want to add a bandpass filter to the output. --------------------------------*---------*--------*----||---ANT | | | | 10pf | | | | - | ) --- XTAL | ) --- C - | ) L | | | / c ) | *----------------------------|/ | | | b |\ | | | 2N2188 \ e *--------- / or any PNP | | \ 100K that'll work | | / GND | \ | | | *-----------------------------------------* | | | | | --- | --- .01uf | | ---------*KEY*----*1 to 4 volts +*--------* | | GND Again, choose L&C to resonant at the desired frequency; one of the two should be adjustable. I got both from the chromatic board of a TV - both were sitting next to the 3579 kc xtal; easy, huh? I didn't use a 2N2188 transistor; rather, I used a x-sistor right off the video board (of the TV). So, don't you dare buy one component for this - just dig through your junk box (or your neighbor's trash for an old TV). With a good antenna (those are the magic words in QRP work) this little peanut-whistle will provide hours of pleasurable QSO's. Oh, 3579 kc has become a national QRP frequency due to the easy avail- ability of these crystals. .... .- ...- . ..-. ..- -. 72, Jeff NH6IL Project 16: Long-Wire Antenna Coupler The following configuration uses an alligator clip and a length of hookup wire to vary the inductance. by trial and error you pick the `tap' by choosing any single coil turn. Before very long you'll find where the the best tap is for your particular xmt'g freq. For tuneup simply hold an NE-2 neon bulb somewhere along the antenna (after the coupler), and tune C1 for max brillance; if the NE-2 won't fire (QRP) use a field strength meter. Run 52 ohm coax from xmtr to the coupler so that the antenna ``begins'' after the tuner. Run a good earth ground! 24 turns #12 wire 6 turns/inch 3 inch diameter TO <----------------*-----------/\/\/\/\/\/\/\/\----------*-------->LONG XMTR | ^ | WIRE | | | <---- --------------------- | / | ---/ | / 140pf | --- variable | /| cap | | *---------------------------------*----------------- | | | | ----- \ / --- GOOD EARTH GROUND - Taken from 140 HAM RADIO PROJECTS FOR NOVICE AND TECHNICIAN (1968) by Bert Simon, W2UUN. Jeff NH6IL Date: Tue, 10 May 94 14:16:38 HST From: Jeffrey Herman <jherman@uhunix.uhcc.Hawaii.Edu> To: Bruce Walker <bruce@Think.COM> Subject: Re: QRP Projects In-Reply-To: Your message of Tue, 10 May 94 19:47:26 EDT Bruce: note that project #12 is a 25 mc output VFO - I'm still drawing it; it would make a nice 12 or 10 meter xmtr. Oh, just for laughs here what project #15 is - it certainly does not belong to QRP (hee hee hee) Jeff *********************************************************** TSB xmitter spark-gap o o---+-----o ant | | ( ) ( L1 ) RFC ( | ( ### ( _______________________________________ ( | | / L2 ) ( | --- C1 ___) ( | --- | ) ( | / |____________|___) (_______ | | | | 833 | 833 | | ### __|__ L3 __|__ |________________o +3000v 700ma .....___ ___..... _|_ __/^\__ UUUUUUUUUUUU __/^\__ ___ .1 uf 5kv | | | | | | | | > | | ### | | <Rg | | | |.001uf > .001uf| | <--- caps rated 1000v | +-)(----+-----)(-+ | | | | | | | | ### | | | | | | | +----------+-----------+ | |_ | _| | |_ | _| UUU o UUU 10v 10a ct xformers ======= \o S1 ======= MMMMMMM | MMMMMMM | | (.)mtr | | o 117v o | o 117v o >D F-24-a 's may be subbed for | carbon mic 833's if supply's are made ### larger. How it works: The 2 tubes form a push pull power oscillator which makes alternating current, but at a radio frequency. This is done by use of L1 , L3, and the 2 little tubes. In this case, the actual frequency is not important, sence the objective is to generate maximum bandwidth...the goal of any 'phone station. C1 is used to obtain maximum power by resonating L1 to L2's natural freq. This RF voltage is stepped up by a factor of 30 to 100X by L2 and sent on to the spark-gap, where the actual RF-to-be-sent is generated. The RFC keeps the ant ckt at DC ground, yet will not short out the RF...which is sent from the sparkgap, to the ant. The ant wants to be one wire, and end fed. No coax required..just hook 'er up and duck. The length of the antenna determines the sending band it will be on. The formula to use to get that length is... Feet = (468/(((F*F) +730 ) -(F*F))) *35.5 F = frequency in Mhz ( rounded off to nearest 100 Khz ) Voice modulation is done by use of a special Carbon Microphone, as used in the 1920's...which can handle several amps. Here, rather than sending RF thru the mic as was done back then, only DC is sent thru. That way, the operator (or inflictor) won't get an RF burn on his lips if he speaks too close to the mic. That modulates the power to the tubes , which varies the intensity of the spark which then puts quite suitable a signal on the air. The itellegibility will match the content of some of the QSO's now on the air. To operate: 1 Place mouth near carbon microphone. 2 Close S1 and adjust C1 for dip in current (mtr) quickly. 3 Make oinking and Mooing noises to indicate your presence to everyone. 4 Open S1 when you get around to it. -- Randy KA1UNW If you get a shock while " MARY HAD A LITTLE servicing your equipment, LAMB! HA! HA! HA! " randy@192.153.4.200 DON'T JUMP! -Thomas A. Edison You might break an expensive tube!