“Kitchen Sink” Radio

An approach to ham radio fun without complexity

Roger G3XBM

www.g3xbm.co.uk A talk given at the Cambridge Radio Club on 12.1.07

© Roger Lapthorn 2007

Tonight

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

My Ethos

• Modest power

• Simple equipment

• Simple antennas

• Small is beautiful

• Simplicity is elegance

• Just enough technology

Homebrew Approach

• Bursts of energy – long periods without building anything sadly

• Go for projects that will get finished• PCBs not required for “one offs”• Projects 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?

• -55dBm

40m Regen Receiver

9 parts, works well

CW/SSB, -85dBm

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

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 >>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 and K2

• Hendricks kits

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

• A “work in progress”

• Kit in the Heathkit style

• 5W on 40, 30, 20,15m

• Narrow CW filters

• Keyer + beacon modes

• Auto-ATU

Elecraft K2

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

Future projects?

• Complete the 1 transistor transceiver• QRP 10m SSB phasing transceiver• PSK16/31 earth comms rig• 136kHz (or 500kHz) activity• 4m transverter• 10m halo• 2m/70cms SSB• Another Fredbox (DSB?)

Commercial Rigs

• FT817, IC703, VX2.

• Avoid costly “soon get bored with” rigs.

• “Shack” fits a desk in bedroom corner

• 80m to 70cms rigs and antennas

• Multi-band simple WIRE antennas.

• VHF/UHF vertical – Spor-E on 6m

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 2 S-points (12dB) down on a decent vertical

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

IC703

• First class QRP radio

• 0-10W 160-6m

• Speech processor

• Auto ATU

• DSP filters

VX2 Yaesu 2m/70cms

• Low cost tiny VHF/UHF handheld

• Pocket sized

• Good performance with longer whip

• Good for holidays

• Get a programmer

Summary

• Build something simple next weekend• Nice to own a few commercial rigs• DXCC with QRP (mainly SSB) possible

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