Doug wrote:
"Jack Painter" wrote in message
news:SR2tc.76990$pJ1.75446@lakeread02...

"Steve (another one)" wrote in message
...
1. RF feedline from ATU to antenna.

This should be coaxial cable with dialectric and shielding designed for

RF.

Never improvise with something such as spark plug wires.

2.(a) Grounding: RF

This does not have to be wide surface area copper, but doing so will not
hurt, and it will allow the combination-use of the RF ground connection to
serve as a lightning protection ground. RF ground does not require a dc-
connection to ground, and is often designed to use capacitive coupling to
ground for sailing vessels and other marine applications where isolation

for

galvanic protection is adviseable.



NO NO NO coax from ATU to antenna, even inside a metal ship! Use GTO wire.
In an emergency repair in the Aleutians I used HV cable from a television
flyback transformer to the CRT anode once and it worked until the ship got
back to civilization. I have corrected many poor performing backstay
installations by replacing RG-8, 214, etc coax running from the ATU to the
backstay with GTO. What a difference in receive and transmit performance.

Use the widest copper foil you can find, at least 3" for the RF ground path.
The wider the better! Smaller sizes and round wire is too high impedance for
proper HF RF grounding.

Flat braid may be used is you have to use it, putting more that one flat
braid in parallel usually helps.
Doug K7ABX


Thanks for these comments, sorry if was a FAQ, I did search first. I
have since asked the same question of Icom UK and their suggestion was
to use the centre conductor of RG213u - having stripped off the outer
shielding. Someone else told me they cut back the centre conductor of
RG213u and used only the shielding which seems very odd as it would have
little insulation.

Anyway, thanks again, I think I now understand the issues and can
assemble something.

Steve