Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

Setting the Stage ● Teens/1920s -> Almost everything was experimental. Very little store bought ham radio equipment available ● > economics forced rigs to be simple and share a lot of technology with consumer radios ● Late 40s, Early 50s -> rigs reflected WWII experience and military surplus equipment/parts available ● Late 50s -> HF bands choked with AM signals drove change to SSB ● Today -> PC in every shack (and most rigs)

Evolution of Ham Radio ● Teens/1920s -> Lots of experimentation. Heavy techie emphasis ● 1930s -> Maturing technology allowed non-techie interests ● Belong to a club, public service, rag chewing, Contesting, DX, more ● 1930s s -> most technology and construction techniques could be replicated in home workshop ● Homebrew stations common ● State of the art construction articles in magazines and books ● Many companies sold parts and and kits

Why Homebrew? Why not just buy a rig? ● High cost of store bought gear vs homebrew  Total Cost includes Manufacturing Cost plus Parts Cost ● Point to Point wiring ● Hand built/tested ● Generic/Commodity parts ● Available time vs cost of store bought gear  Changed over past several decades ● Peer pressure  Homebrew stations featured in magazines  Techie roots ● Homebrew met performance requirements of most hams

Vintage Homebrew Ham gear built in the late 20s through the 60s by individuals interested in using it. Typically based on magazine articles with minor enhancements or changes to meet the requirements of the constructor.

Late 20s Receiver ● Two tube regen common in many late 20s/early 30s shacks  Breakthru late teens invention  Tricky to use ● Based on 1928 QST articles ● Covers 80, 40 and 20 mtrs with plug-in coils ● Limited usefulness today  Controls interact  Easily overloaded  Hum above 5MHz

Early 1930's Transmitter ● Tuned plate/Not Tuned grid (TNT) CW Transmitter ● Popular late 20s/early 30 ● Used broadcast rcvr parts including tubes ● Coils for 80 and 40 ● Runs about 10 watts ● Has personality but usable  Microphonic  No bandspread/calibration  Hand Capacity  Exposed high voltage ● I've made several contacts using it

1940 Portable Transmitter ● Hero of Hallettsville  Used to provide emergency communications during June 1940 south Texas flood ● QSL - 40 design  Several versions in QST  Ran watts  6L6 / xtal controlled / CW / QSL card size ● Original / as found

Three Tube Superhet ● Based on 1941 QST Design ● Step beyond 2 tube regen ● Converter stage followed by 1700KHz regenerative IF ● Plug-in coils for 80 and 40 mtrs ● Primitive crystal filter ● Headphones only ● Similar designs in ARRL Handbook thru 1965 ● Works surprisingly well

Two Tube 1940 Transmitter ● Many classic 6L6 transmitters hard on crystals and tubes ● Gentler design based on a watt AM/CW transmitter ● 6J5 crystal oscillator driving a 6L6 final ● Plug-in coils for 80 and 40 ● Nice match for the three tube superhet

1951 Novice Station ● Novice license introduced in 1951 ● Initially only HF privilege was 80 mtr cw ● Station needed to be inexpensive and easy to build  Wooden chassis  Common parts  Homemade coils ● 1951 QST designs ● Two tube regenerative receiver ● One tube 10 watt transmitter  3 to 4 watts output ● Separate power supply ● Works but challenge to make contacts

Late 50s Mobile AM Transmitter ● watt AM transmitter ● Appears to be late 50s design ● Easily fit under 1950s dashboard ● Probably used with car radio and SW converter ● Changing bands/freq while moving would have been dangerous  Change crystal  Peak osc stage  Dip and load final

HBR-16 ● Popular/classic receiver of late 50s thru late 60s ● Various versions - > 30 articles in QST ● Mine built by David Hoffman, W0FGV, in Northfield, MN ● 16 tubes ● Double conversion ● Band change required changing three coils ● Mine had a resident mouse  Ruined several tube sockets ● Work in process

Paddles / Bug / Key ● Not all homebrew is Electronic ● Keyer paddles ● Miniature bug ● Straight key

Construction Articles and Help ● Current magazines  Electric Radio:  QST  CQ ● Web sites  Google what you are looking for: ● Mail reflectors  mailman.qth.net Mailing Lists: ● Reprints (including Radio Handbooks and QST magazine)  Lindsay Publications  Back issues of QST on CD-ROM

Parts ● Start with a list, shoe box, patience ● Hardware store for screws, nuts, bolts, gun blueing ● Friends ● Swapmeets  June 3M swapmeet ● Mail order  Antique Electronic Supply  Bob's Antique Radio & Electronics ● eBay  Can be expensive

Safety ● Voltages present can be lethal ● Power down and discharge caps ● Know where the high voltage is ● One hand in the pocket ● Add safety features  Fused 3 wire line cord  No exposed high voltages  AC line isolation transformer  Headphone isolation transformer

Getting on the Air ● Miscellaneous operating / CQs works ● QRP calling frequencies: ● Vintage Nets / Round tables. Listed in Electric Radio or at ● Antique Wireless Association Vintage Ham Radio Contests: ● Classic Exchange or “CX”: