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

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Page 1: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

Vintage Homebrew

● Setting the stage Technology / economics / history

● Examples● Vintage homebrew hints and tips

Page 2: 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

● 1930 -> 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)

Page 3: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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 - 1960s -> 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

Page 4: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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

Page 5: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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.

Page 6: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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

Page 7: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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

Page 8: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

1940 Portable Transmitter

● Hero of Hallettsville

Used to provide emergency communications during June 1940 south Texas flood

● QSL - 40 design

Several versions in QST 1938-1941

Ran 5-100 watts

6L6 / xtal controlled / CW / QSL card size

● Original / as found

Page 9: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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

Page 10: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

Two Tube 1940 Transmitter

● Many classic 6L6 transmitters hard on crystals and tubes

● Gentler design based on a 1940 10 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

Page 11: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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

Page 12: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

Late 50s Mobile AM Transmitter

● 60-90 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

Page 13: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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

Page 14: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

Paddles / Bug / Key

● Not all homebrew is Electronic

● Keyer paddles

● Miniature bug

● Straight key

Page 15: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

Construction Articles and Help

● Current magazines

Electric Radio: http://www.ermag.com/

QST

CQ● Web sites

Google what you are looking for: http://www.google.com● Mail reflectors

mailman.qth.net Mailing Lists: http://mailman.qth.net/mailman/listinfo● Reprints (including Radio Handbooks and QST magazine)

Lindsay Publications http://www.lindsaybks.com/

Back issues of QST on CD-ROM http://www.arrl.org/catalog/index.php3?category=CD-ROMs

Page 16: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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 http://www.tubesandmore.com

Bob's Antique Radio & Electronics http://www.radioantiques.com/ ● eBay

Can be expensive

Page 17: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

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

Page 18: Vintage Homebrew ● Setting the stage  Technology / economics / history ● Examples ● Vintage homebrew hints and tips

Getting on the Air

● Miscellaneous operating / CQs works

● QRP calling frequencies: http://www.njqrp.org/data/qrp_freqs.html

● Vintage Nets / Round tables. Listed in Electric Radio or at http://www.qcwa.org/chapter029-01.pdf

● Antique Wireless Association Vintage Ham Radio Contests: http://www.antiquewireless.org/amrad.htm .

● Classic Exchange or “CX”: http://qsl.asti.com/CX/