I had originally intended to publish a more extensive article, but havemoved on to other projects. I am sharing here some tips that you mayfind useful. I always coveted the Heathkit Twins, but could neverafford them. A friend was cleaning out his basement and passed thesealong at a reasonable price. I now had the opportunity to enjoy adream from the past.
These are the early filter type sideband rigs from the sixties, so be awareof their limitations. The spurious output performance is better thanthe Heathkit Marauder, the previous SSB rig. Unless the trap wasadjusted carefully, the spur on 20 meters was a problem. Drift wasgreatly improved by the new LMO in the twins. The Marauder occupieda monster Apache cabinet and was similar in appearance to the Apache. The SB401 and SB301 are significant improvements over the earlyversions. In particular, the transmitter is much easier to switchfrom split to transceive. A small reed relay to switch the VFOaround would correct this in the early 400. The 300 is an excellentreceiver, especially if it has the accessory AM and CW filters. The301 was friendlier to the 6 and 2 meter converters, but no othersignificant changes.
- Search the Boat Anchor Manual Archive (BAMA) for Heathkit SB-303 for manuals and documents (using Google) About. RigReference.com aims to become the most comprehensive reference guide for ham radio equipment. If you have any questions or suggestions, or if.
- SB-303 Assembly manual.zip: 19.800 Kbytes: SB-310 Service manual.zip: 3.631 Kbytes: SB-401 Manual.zip: 9.055 Kbytes: SB-500 2-Meter Transverter Schematic.zip. This is all the manuals for Heathkit. If you want to see manuals from other manufactories you can click on the manufactory menu in.
- For sale is one used HEATHKIT SB-303 solid state ssb receiver assembly and operation manual form no. A schematic is loose inside the front cover. We are required by law to report the actual sale total not including shipping costs.
- Complete Transceivc capabilities are available when the Transmitter is used with the Healhkit Model SB-300, SB-SOl, or 83-303 Receiver. The Transmitter can also be used with other receivers by installing the SBA-4014 Crystal Accessory Kit in the Transmitter. This Transmitter is compatible with the Heathkit Model SB-200 SSB Linear Amplifier.
The SB303 was an all solid state receiver, the last in the series. Iplan to do a write up on this project later, as this is part of mypermanent collection.
Compactron tubes are used extensively in the transmitter. These are gettingscarce. Stock up on them while you still can. The receiver has onlyone compactron. It can be replaced with a 12AU7 and 6AU6, if you areclever.
The transmitter was improved by inserting 10 Ohm resistors at various B+points. It did give the kit builder a “second chance” ifthere were shorts. The resistors smoked to alert the owner oferrors. Perhaps you could recover from them if you killed the powerquickly. More significantly, the 82K resistor on the terminal boardunderneath in the front was changed to 2 Watt. You should check thisbefore power up. As a minimum, the CW & Tune Drive adjust willnot work right if the value goes up. If it goes down in value, thebalanced modulator diodes will fail and other ugly things will occur.
Post subject: Heathkit SB-303 manual available for download. Posted: Nov Fri 23, 2018 10:41 pm. Member: Joined: Feb Sat 11, 2012 12:44 am Posts: 317 Location: Islip, Long Island, NY This file contains a cleaned up version of K5JXL's scan of the Heathkit SB-303 Solid State Ham Band Receiver.
The antenna relay (not the main control relay) also develops a permanentmagnetism that causes it to hang up in transmit mode. I have seenpeople put thin pieces of plastic on the pole piece to fight this. The easiest way to correct this is to use a powerful tape headdemagnetizer to reduce the residual magnetism. Then swap the wiresto the coil of the relay; it will probably magnetize again, but itwill take quite a while. If it happens again, just swap them back.
Follow the manual during alignment. Be sure to perform the neutralizationcarefully. Power output will be 100 Watts, but lower on 15 and 10meters for sure. If you get 75 Watts on 10 Meters, call it good. Use the grid drive meter to determine if the power is not up tosnuff. If you are not getting enough grid drive, changing the finalswill not correct it. Low B+ on the low voltage or resistors thathave drifted in value can cause the exciter to not deliver enoughdrive to the finals to operate properly.
Operating the Heath Twins as a complete station requires the constructionof three cables each exactly 24' long from RG-62/U coaxial cable (90 Ohms)exactly as described in the SB300/301/303 receiver manual. Yes, thetransmitter connection is described in the receiver manual. The cable partscame with the receiver, not the transmitter. Go figure. Anyway, theimpedance is not relevant. The shunt capacitance per foot is very critical,since it can detune the circuits which are used to link the receiver to thetransmitter. The crystal HF oscillator in the receiver is used to drive thetransmitter. The USB and LSB BFO crystals in the receiver are used tooperate the transmitter. In the SB400, you may find it advantageous toremove the BFO crystals EXCEPT THE CW crystal, to prevent a beat note onreceive. The CW crystal is required to operate CW and Tune modes. I do notknow if the 401 requires this, but try it if you have problems. The LMO(VFO) is linked between the two rigs for transceive, and is the ONLYoscillator switched to go to split frequency operation. In a pinch, I haveheard that some people will disassemble a junked AM car radio antenna,which often uses a similar coax cable. I have a quantity of the correctcoax on hand, which I have often mailed to those who need this item.
The LMO sometimes develops a jump or warble as you tune in a station that is annoying in CW or SSB modes. This is a link to fix that problem: http://nebula.wsimg.com/d6a8106142d2492dec285d95be47aaf6?AccessKeyId=D1250C433DB440D6B60D
NOTE: The SB400/401 often comes WITHOUT the crystal pack. You do not needANY crystals (except the CW crystal) installed to operate the transmitter,if you are using it with a Heath SB300/301/303. For troubleshootingpurposes, to operate the SB400/401 as a stand alone unit, simply 'borrow'one or more crystals from the SB300 until you can get the SB400 running.Then connect them as described above. Note also that you have to re-alignthe HF oscillator coils as described in the manual as well as some otheradjustments. Since the crystals for 29.0 to 29.5 and 29.5 to 30 MHz coveredterritory for AM and FM, many did not install the crystals in a SSB/CW onlyrig. Again, the receiver came with the whole set; use the cables describedabove and you have no problem.
UPDATE -I have heard one report for VFO changing frequency when switching to transmit. I have never encountered this myself. I found the voltage regulation built in OK. The person told me he added another VR tube. I am not sure that the power supply capacitors, resistor values drifted, or something else may have been off. But this is added as a cautionary note, in case you have problems.
Good luck with your restoration. These have nice audio on transmit. TheALC circuitry works better than the transceiver SB100.
GUEST UPDATE 4/19/2014 -I was studying the schematic for the SB-300 and found an error on theheterodyne crystal oscillator switch wafer labeled BS1R. The commonconnection for crystals Y6, Y5,Y2 and lastly Y1 should be grounded. Rightnow without any connection, one side of all of these crystals are floating.They do have it correct for Y3, Y4,Y7 and lastly Y8. This is just aschematic drawing mistake and obviously the wiring of the receiver iscorrect since the receiver works!
73,
Joe, W3GMS
UPDATE 7/12/2016 -One more Heathkit Twins glitch is addressed at:http://www.boatanchor.com/heath/SB300-SB301%20Voltage%20Regulation%20.pdf.I have not personally tried this modification myself, but it appears to be carefully researched and implemented. Please keep in mind that the SSB equipment of this day was not very stable; people were using SB-10 adapters driven by DX-100 VFOs that were barely stable enough for AM, marginal for CW, and totally unacceptable for SSB. Comparing first or second generation SSB gear to modern rigs is just not reasonable.
CAPE COD, MA WB1U will operate 1400Z Sep. 28th-21002 Sep. 29th. to commemorate Marconi Station's 95th Anniversary. Operation wilf be in the General portions of 15, 20. 40. and Novice portions of 10 and 80 meters (CW and SSB). For a certificate, send an SASE to Ray Hilson. 6 Sherman Place, Norway CT 06851 USA. EE
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Coniirtued from page 77
legally end our old music business companies. This doesn't affect 73, other than it'll give me more time lo get on the air and have some fun and lo pursue my work with cold fusion. I enjoyed the music business, but 'Tve been there, done that.' Ten years was more than enough.
I was not surprised b the recent class action suit against ihe six major music companies i five are foreign-owned) for price fixing. But then the whole industry is corrupt, as i've discussed in my past editorials. The big winners are the six majors and big record store chains. The big losers are 98^ of the performers, U)0% of the independent record companies, and 100% of the independent record stores. Capitalism works fine until companies get big enough or work in secret groups to control distribution and prices. Lobbyist payments to Congress keeps the Feds at bay, I've testified al Congressional hearings where it was quite clear that (he committee chairman was safely in the music industry's pocket. The industry people, whom I kneu well. laughed uhout it.
The majors wltc candid. They haled the impact I was hav ing in my efforts to build the market share for independent record companies, but my CD Review vus selling about S30 million of
Continued on page 83 Radio Today - September 1996 79
And all bought at bargain prices!
Shane R Brady WB2WPM 34 Rosewood Drive West Seneca NY 14224
earned my Novice license 22 years ago, after seeing a ham radio demon* straiion as a Boy Seoul some 10 years earlier. Recently married and unable to afford new equipment, when I heard thai a local ham was selling a Heathkil SB-102,1 went for it. That SB-102 and a 40 meter dipole were my introduction to actual QSOs+
I remember looking through the Heathkit catalogs, Irving to imagine a si at ion with all the matching accessories for my SB-102. !'he XYL got me started by giving me the matching SB-630 station console for Christmas, l itis had a 24-hour digital clock, a phone patch, an SWR meter, and a 10-minute timer, all in one. I then added the matching SB-600 station speaker Not a shabby-looking station for a Novice in 1974. The SB* 102 is a 13-tube IIF SSB/CW transceiver. rated at ISO watls input—80 watts more than most of today's radios—running a pair of 6146Bs as finals.
When I upgraded to Advanced, the SB-102 got me contacts with UA. ZS. VK, and XX. I added the optional 400 Hz filter for CW, and what i difference that filter made!
Sure. I sold the SB-102 and went on to a solid-state synthesized radio with 100 memories and computer-controlled microprocessors.. but I couldn't forgel rn vision: to have a complete line of Heathkit radios and accessories.
Building the dream
Several years ago I heard about a retired ham with some old gear to sell. That isit changed my shopping habits at ham tests. There was an SB-102 and an SB-200 1 kW amplifier. The SB-200 is still an extremely popular 1 kW amplifier It uses a pair of 572B tubes in parallel for finals. Together the SB-102 and the SB-200 were a popular combination in the late '60s and earlj *70s+ We worked out a great deal; he jusl wanted them to go to a good home and was not interested in the dollars.
Finding the pieces
At a local ham auction* I ran across an SB-610 monitor seopc which also matchcd the famous Heathkit 'SB green line' of equipment. Now I had live matching picces from the SB line. The station was starting to look like the Heathkit catalogs of 20 years ago, I was hooked, I had to have ¿ill the pieces to the Heathkit SB line!
Packet radio is a nice way lo find 'wanted' equipment* and I've had great succcss finding bargains for older equipment. A couple of messages out on
So what do I do with all of this outdated equipment? I have fun with it!'
- Photo A, WB2WPFs Heathkit collection. SO 73 Amateur Radio Today • September 1996
Clearing a spot an a side table. 1 made a new home for my old friends, I had kept my SB-600 speaker and SB-630 console; these too joined the new family.
As a Novice in the eariy '70s, it seemed to me that four out of five QSOs were with hams who had Heathkil equipment. Now, in the 1990s. 1 was trying to make contacts like I did 20 years ago, with so-called obsolete equipment.
Does that Heathkit combination still work? You bet it docs! No, il dt^esn't have the 100 memories, and 1 do have to wait a couple of minutes for the lubes to heat up. But what it does very well is make contacts. You're not going to hear signals coming in at less than 0. i i on a crowded band, hut how often are you really under those conditions? Remember, a clean signal from 2(1 years ago still sounds the same as a clean signal from a state-of-the-art transmitter today.
packet and soon I h;id added the SB-650 digital (niie-iubes) frequency display and the SB-620 spectrum analyser, for under S25 each. Yes, the) both worked when I plugged them in. Another packet request and I hau two SB-500 2 meter transverters added to mv collection (at nesxt-Lo-nothing prices). The SB-500 also uses 6146 finals for 50 waLts output for SSB and CW.
The next piece took some ads in the ham classifieds. 1 had only seen one SB-640 in my life, and that was ears ago al Dayton. The SB-640 is a remote YFO that interfaces with the SB line of transceivers for working split frequency.
The hardest piece to locate was the SB-110 6 meter transceiver. Most people hang on u> these '60s vintage rigs, which use 6146 lubes for finals for 180 watts PEP on SSB and 150 watts CW.
Haiiitesis will yield a bumper crop of old tube-type Hatth equipment. I've purchased complete working HP rigs for $20!
I've since added the SB-300 and SB-303 receivers, along with their
Photos by WB2JFP
Photo B WB2WPM at his station.
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matching SB-644A remote VFO. All working, and all obtained ai bargain prices.
So what do I do with all of this outdated equipment? I have fun with it! When visitors comc to the shack, most arc in awe of all those dials and gleaming knobs. It's almost a shame to tell them thai, averaged out, I have Jess than $35 per piece invested in this sub-hobhy. That's less than a used state-of-the-art rig!
Am I finished wiih my collecting? No way. There is still an SB-313 shortwave receiver out there waiting for me, the last piece I'm missing for my collection! Besides, I still need more basket eases to combine with other basket cases, to come up with working units. Why do I
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matching SB^tOO and SB-401 transmitters, to the collection. These twins were known as the 'poor-man's Collins.' HW-lOOs and HW-lOls have joined the family as well, along with many green accessories such as wattmeters, phone patches, keyers, and SWR bridges.
No, not everything works when I get it, but in most cases all [hat is required is replacing a tube or two and a quick tune-up. At hamfests there are always boxes of tubes for sale. The average price for a tube is $2, but many times they can be found for only $L
Manuals are worth their weight in gold when working on this older equipment. 1 make copies of all manuals and store them away. Tm even collecting if
When visitors come to the shack, most are in awe of all those dials and gleaming knobs.'
manuals for equipment I don't have yet, just in case I come across it someday. With the manuals, tune-ups are a cinch, as in mosi cases all you need is a known frequency source and a YOM. Heathkif s famous siep-by-step instructions will lead you through complete tune-ups, if need be.
Naturally, I've added Heath's last line of SB equipment to my collection. At another operating position, sits the all-solid-state SB-104A transceiver and its matching SB-604 speaker and power supply, the SB-6I4 monitor scope, and the SB-634 station console and its need more and what am I going ro do with all of these Heaihkit radios? Funny, that's what N2INY, my XYU asks.
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