Ferrets, rats and crabs…..and CATs too.

Getting the best from a limited QTH

David Aslin G3WGN TARS Meeting August 28th 2015

1961 Introduction to radio 1963 Joined RSGB as SWL A4677 1967 Licensed as G3WGN, aged 16 1967 - 1970 160 & 80 only; home-brew TX 10W; AR88D and

Lafayette KT-320 1970 - 1978 NFDs, GB3MCG; first commercial rig: Yaesu FT505 400W 1978 - 1990 Work, family, work, family… 1990 - 2000 QRP, DX and contests; 80m DXer 2000 - 2010 WJ6O in Silicon Valley; hired gun contest operator 2010 - 2015 G3WGN and M6O Devon; search for DX & contest site

G3WGN background

From This…

G3WGN/Warwickshire 1968

Sshh! don’t mention the Joystick!

…To This…

G3WGNGQRP 5278Cheshire 1978

Elecraft K2 10WHomebrew 1W on 40mLafayette KT-320

…To This…

M6T 1998

…To This…

G3WGN Herefordshire 1998

Yaesu FT1000MP (now with G6GLP!)Heatherlite Explorer then ACOM 2000A

220 countries on 80m in 3 years

Go West young man…

…To This…N6RO 2002

N6RO

…Then This…K6IDX 2000-2010 K6IDX

…and This...WC6H

…and Back Again

G3WGN Spreyton 2015

Escape noise, small garden, lousy site, weather, XYL… TK/G3WGN SV8/G3WGN EU-072 T32C Dartmoor – SOTA High Willhays TX6G E6GG September 15th- 29th 2015

Globetrotting

Successful stations plan antennas as a SYSTEM Optimise what you have:

Pick the right antenna Pick the right feeder Look after your feeder Kill that noise

Lessons learned

Antenna System Design

Ground-mounted Vertical

Feed with 20m Westflex 103 Antenna gain: -2.4dBd Coax loss: -0.32dB System gain: -2.72dBd

Dipole at 9m

Feed with 20m RG58 + another 10m RG58 up the mast

Antenna gain: 0dBd Coax loss: -2.5dB System gain: -2.5dBd

Antenna System Design

Dipole at 9m

Feed with 20m Westflex 103 + 10m W103 up the mast

Antenna gain: 0dBd Coax loss: -0.48dB System gain : -0.48dBd

2 element YAGI at 9m

Feed with 20m RG58 + 10m RG58 up the mast

Antenna gain: 4dBd Coax loss: -2.5dB System gain: +1.5dBd

What’s the terrain like? Model antenna versus height versus direction with HFTA by

N6BV Put the antenna at the optimum height if you can If you need radials, use plenty – they don’t have to be long if

you don’t have space If you have a choice of location match it to the antenna type

Pick the right antenna

Major performance impact: Antenna Support Terrain Feeder Matching Grounding

Minor performance impact (<100MHz): Connectors

Documentation Maintenance

The antenna system

Antennas on the beachVertical Dipole Arrays

17m and 10m at TX6G

Where to next?

E6GG North Coast of Niue

What’s missing?

Where to next?

E6GG North Coast of Niue

What’s missing?

NO BEACH!

Antenna Choices

TX6G Lots of beach – verticals by the sea! Shacks next to the beach Lots of nearby noise sources VDAs for 10 through 20m Elevated quarter waves for 40 and

30m Vertical/inverted-L for 80/160m Pennant for RX

E6GG No beach; 25m high cliffs Shack 140m from sea Low noise site? Dipoles for 10 through 20m, 1.0λ high Elevated quarter waves for 160

through 30m Beverages for RX

Horses for courses

Antenna at home

Folding Hexbeam

2 elements per band 6-10-12-15-17-20mG3TXQ electrical designFolding Antennas DL1LEU manufacturer

Does it work?

2015:220 DXCC entities/countries900 band slots21 countries on 6m

Actually, anything works - 1

150W lightbulbs in phased arrayby Tom Schiller N6BT

Tom is former founder/owner of Force 12 antennas

Actually, anything works - 2

Enjoyment vs antenna typeaccording to N6BT

Don’t waste power or signal Feeder is cheaper and easier than big antennas and can have more gain! Unless you have very short runs or are on 160m, RG58 or Mini-8 are almost never

the right choice: 1950s product, no longer made to MilSpec Poor screening High losses on HF

Modern coax is much better: Aircell 5 or Aircell 7 (Nevada); Airborne 5 or Ultraflex 7 (Martin Lynch) Even better: Westflex 103 (Henry Westlake)

Pick the right feeder

Feeder loss matters

Running 100Watts?Here’s what is at your antenna:

1dB loss (40ft/12m RG58 at 10m)80W2dB loss (160ft/25m RG213 at 10m)63W3dB loss (120ft/36m RG58 at 10m)

50W

Or, if you have 40ft feeder:RG58: 10m band have 80W at the antennaRG213: 10m band have 89W at the antennaW103: 10m band have 95.5W at the antenna

Feeder change brings the cheapest dB you can have!

Take measurements so you can spot changes Inspect regularly Use high quality connectors, properly waterproofed Everything wants to get into your coax

Water Salt Critters

Look after your feeder

Flushed with success at T32C

Rats!

In UK:Squirrels?Pets?Enthusiastic gardeners?

We are trying to optimise SYSTEM performance, not just antenna performance

20dB (S3) of noise makes 1kW seem like 1W Reducing noise by 6dB is like swapping your dipole for a 3 or 4 element

beam Verticals are great for picking up noise, go horizontal at home if you can Don’t let common mode noise ruin your day or DX

Opportunity: W0GJ at the RSGB Convention: Is 3dB worth a divorce?

Kill that noise

‘Electronic smog’ is everywhere, but you can tame (some of) it Feeders don’t only feed signals, they feed noise unless you stop

them Keep noise out with ferrets

At antenna feedpoint At shack entry point On mains cables and interconnects

Dealing with noise

The Reverend Jim K9YCFerret trainer extraordinaire

K9YC ferrite chokes

Use FT240-31 toroids or Type -31 clip-onsPut enough turns on! HF 3-5 LF 5-9+

See Jim’s Cookbook audiosystemsgroup.com/RFI-Ham.pdf

Ian GM3SEKHoney, I shrunk the ferrets!

http://www.ifwtech.co.uk/g3sek/in-prac/inpr1005_ext_v2.pdf

M0PCB version of GM3SEK ferrite choke

Try stuff – you may like it Competing with yourself drives continuous improvement Simple wire antennas work Pick the right antenna for your location Choose the right feeder and look after it Kill that noise If all else fails, operate from somewhere else…

Lessons

What about the CATs?I thought you said there’d be CATs?

CAT – station automation

CAT – Computer Aided Transceiver

Vertical dipole arrays: RadCom December 2014, p34 and http://www.f4bkv.net/antenna-vda.html Folding Antennas Hexbeam: RadCom April 2015, p26 and

www.foldingantenna.com HFTA by N6BV: ARRL Antenna Book 21st-23rd Editions Ferrite chokes:

K9YC: audiosystemsgroup.com/RFI-Ham.pdf K9YC: audiosystemsgroup.com/CoaxChokesPPT.pdf GM3SEK: http://www.ifwtech.co.uk/g3sek/in-prac/inpr1005_ext_v2.pdf

Finding and killing noise: http://www.nccc.cc/pdf/Sep-K9YC-RFI2013.pdf “Everything works” N6BT: http://www.ok1rr.com/index.php/antennas/94-

everything-works

Further Reading

Questions?

Where to next?

E6GG North Coast of Niue

6Gs team that brought you TX6G last year

September 15-29 2015

www.e6gg.com