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Ferrets, rats and crabs… ..and CATs too. Getting the best from a limited QTH

Ferrets, rats and crabs… ..and CATs too. Getting the best from a limited QTH. David Aslin G3WGN TARS Meeting August 28 th 2015. G3WGN background. 1961 Introduction to radio 1963 Joined RSGB as SWL A4677 1967 Licensed as G3WGN, aged 16

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Ferrets, rats and crabs… ..and CATs too. Getting the best from a limited QTH

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  1. Ferrets, rats and crabs…..and CATs too.Getting the best from a limited QTH David Aslin G3WGN TARS Meeting August 28th 2015

  2. G3WGN background 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

  3. From This… G3WGN/Warwickshire 1968 Sshh! don’t mention the Joystick!

  4. …To This… G3WGN GQRP 5278 Cheshire 1978 Elecraft K2 10W Homebrew 1W on 40m Lafayette KT-320

  5. …To This… M6T 1998

  6. …To This… G3WGN Herefordshire 1998 Yaesu FT1000MP (now with G6GLP!) Heatherlite Explorer then ACOM 2000A 220 countries on 80m in 3 years

  7. Go West young man…

  8. …To This… N6RO N6RO 2002

  9. …Then This… K6IDX 2000-2010 K6IDX

  10. …and This... WC6H

  11. …and Back Again G3WGN Spreyton 2015

  12. Globetrotting 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

  13. Lessons learned • 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

  14. Antenna System Design Dipole at 9m Feed with 20m RG58 + another 10m RG58 up the mast Antenna gain: 0dBd Coax loss: -2.5dB System gain: -2.5dBd Ground-mounted Vertical • Feed with 20m Westflex 103 • Antenna gain: -2.4dBd • Coax loss: -0.32dB • System gain: -2.72dBd

  15. Antenna System Design 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 Dipole at 9m • Feed with 20m Westflex 103 + 10m W103 up the mast • Antenna gain: 0dBd • Coax loss: -0.48dB • System gain : -0.48dBd

  16. Pick the right antenna 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

  17. The antenna system • Major performance impact: • Antenna • Support • Terrain • Feeder • Matching • Grounding • Minor performance impact (<100MHz): • Connectors • Documentation • Maintenance

  18. Antennas on the beachVertical Dipole Arrays 17m and 10m at TX6G

  19. Where to next? E6GG North Coast of Niue What’s missing?

  20. Where to next? E6GG North Coast of Niue NO BEACH! What’s missing?

  21. Antenna Choices Horses for courses 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 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

  22. Antenna at home

  23. Folding Hexbeam 2 elements per band 6-10-12-15-17-20m G3TXQ electrical design Folding Antennas DL1LEU manufacturer

  24. Does it work? 2015: 220 DXCC entities/countries 900 band slots 21 countries on 6m

  25. Actually, anything works - 1 150W lightbulbs in phased array by Tom Schiller N6BT Tom is former founder/owner of Force 12 antennas

  26. Actually, anything works - 2 Enjoyment vs antenna type according to N6BT

  27. Pick the right feeder • 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: • Aircell5 or Aircell 7 (Nevada); • Airborne 5 or Ultraflex 7 (Martin Lynch) • Even better: Westflex 103 (Henry Westlake)

  28. Feeder loss matters Running 100Watts? Here’s what is at your antenna: 1dB loss (40ft/12m RG58 at 10m) 80W 2dB loss (160ft/25m RG213 at 10m) 63W 3dB loss (120ft/36m RG58 at 10m) 50W Or, if you have 40ft feeder: RG58: 10m band have 80W at the antenna RG213: 10m band have 89W at the antenna W103: 10m band have 95.5W at the antenna Feeder change brings the cheapest dB you can have!

  29. Look after your feeder • 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

  30. Flushed with success at T32C

  31. Rats! In UK: Squirrels? Pets? Enthusiastic gardeners?

  32. Kill that noise 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?

  33. Dealing with 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

  34. The Reverend Jim K9YCFerret trainer extraordinaire

  35. K9YC ferrite chokes Use FT240-31 toroids or Type -31 clip-ons Put enough turns on! HF 3-5 LF 5-9+ See Jim’s Cookbook audiosystemsgroup.com/RFI-Ham.pdf

  36. Ian GM3SEKHoney, I shrunk the ferrets! http://www.ifwtech.co.uk/g3sek/in-prac/inpr1005_ext_v2.pdf

  37. M0PCB version of GM3SEK ferrite choke

  38. Lessons 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…

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

  40. CAT – station automation

  41. CAT – Computer Aided Transceiver

  42. Further Reading • 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

  43. Questions?

  44. Where to next? E6GG North Coast of Niue 6Gs team that brought you TX6G last year September 15-29 2015 www.e6gg.com

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