“Kitchen Sink” Radio

Ham radio fun without complexity

Roger G3XBMwww.g3xbm.co.uk

Tonight

• My approach• Homebrew techniques• Ideas for homebrew fun• Useful links• Good kits• Good value commercial rigs

My Ethos

• Modest power

• Simple equipment

• Simple antennas

• Small is beautiful

• Simplicity is elegance

• Don’t waste money

Homebrew Approach

Bursts of energy – long gaps without building much

• Go for projects that will get finished• PCBs not required for “one offs”• Projects that don’t need lots of test gear.• Go for good kits• Hasn’t got to be amateur radio related.• Use the gear you make/own.

Components Choice

• Ugly construction

• Discrete parts

• VXO/crystal controlled

• Standardise on parts: 2N3904/6, MPF102, T50-2, T50-6, 0.1u, 10u, 1k, 10k etc

• Re-use parts

• Recycle boxes

The Humble Crystal Set• Simplest radios to get going

• Possible to hear real BC DX on HF

• More to them than you might think

• Amateur band DX reception possible

• -55dBm

40m Regen Receiver

9 parts, works well

CW/SSB, -100dBm

Single FET transceiver• Sensitive, stable, non-fiddly, regen RX

• 1 active device

• Stable, crystal controlled, TX

• 14 parts !

VLF/LF Converter

Micro 80

4 transistor HF transceiver

PA is the mixer

Pixie

250mW HF transceiver

PA is the mixer

Breakthrough problems

OXO HF QRP Transmitter

Any HF band, 1W, VXO controlled

Pipit 15m CW transceiver

Kitten 10m CW transceiver

Pipit derived cct.

0.5W RF out

0.5uV sens.

Full break-in

25kHz VXO

5 transistors

Fredbox 2m Transceiver

Homebase 10 Antenna

• Simple horizontal halo for 28MHz

• Low cost, easy to build and tune up

• Works well

70cms Moxon Antenna• Made in 30 mins from a metal coat hanger !• 3-4dB forward gain• 100 degree -3dB points

• Best DX 327kms with 5W

Earth Mode Communications

• Communicating at <10kHz through the ground • Use audio power amps and ground rods• Ranges 0-10kms (typically <1km) • PC based RX/filters & QRSS for greater range

Useful “Simple” LinksHOMEBREW

– GQRP club www.gqrp.com/ – Rick Anderson www.tricountyi.net/~randerse/radios.htm – JF1OZL www.intio.or.jp/jf10zl/ – Harry Lythall web.telia.com/~u85920178/ – Gollum’s Xtal RX

www.oldradioworld.de/gollum/index.html – Hans Summers www.100megsfree2.com/hans/ – N4DKD www.n4dkd.com/ – G3XBM www.g3xbm.co.uk

KITS– Elecraft www.elecraft.com – Small Wonder www.smallwonderlabs.com/– Hendricks QRP www.qrpkits.com/

Some Good Kits

• MFJ Cub• Elecraft T1 ATU• Elecraft K1, K2 and K3• Hendricks kits • SoftRock RX

MFJ Cub

• 15m 1W QRP CW

• 8000kms DX with a dipole

• Easy 3-4 hour build

• Decent superhet RX

Elecraft T1 Auto-ATU

• Matches 160-6m

• Instant retune when band changing FT817

• No-hands retune from 80-10m

• 6hrs build

Elecraft K1 4 band CW Transceiver

• Excellent kit in the Heathkit style• 5W on 40, 30, 20,15m • Narrow CW filters• Keyer + memory modes• Auto-ATU• Works well

Elecraft K2

“The best kit in the world producing a first class HF transceiver”

K3 now available

Future projects

• 500kHz QRP TX

• 10m QRP DSB transceiver

• Improved single FET transceiver

• A DSB Fredbox

• Earthmode comms tests with QRSS

The G3XBM Shack• Fits in corner of spare bedroom

• Homebrew rigs plus FT817 and IC703

• “Lab” in back of the garage

FT817

• Simply the best HF/VHF rig for the price

• Worked 4 continents on SSB handheld!

Miracle Whip

• Auto-transformer matched 1.5m whip

• With counterpoise is just 2 S-points (12dB) down on a decent vertical

• DX 11000kms from the bedroom table with 5W SSB!

IC703

• First class QRP radio

• 0.5 - 10W 160-6m

• Speech processor

• Auto ATU

• DSP filters

Summary

Build something simple this weekend!

• Nice to own a few commercial rigs• DXCC with QRP SSB and CW possible with

simple antennas (even handheld)• Operate – use the bands• Call CQ• Diversify • Have fun!