"Jim Carriere" wrote in message
...
ccwillwerth wrote:
Hi, I am about ready to cover my Cub type airframe, but need a place to
attach a com antenna. I was considering brazing a plate to the airframe
so that it would be just under the fabric. The antenna is the type that
has a ceramic insulator on the bottom of the antenna that insulates the
stainless steel antenna from the airframe. Does the antenna need a large
plate for a ground plane or will a small plate be sufficient? If a
ground plane is required, can the copper foil tape be used on the inside
of the fabric as the ground plane?


Two comments. One is that the steel tube fuselage will be an adequate
ground plane if the attach plate is electrically connected to the fuselage
tubes.

Two, that wire whip antenna was just fine for the day in which we had 90
channel radios and didn't go much above 124 MHz.. Do you and your radio a
favor and get one of those fiberglass whips that have the word "broadband"
in their descriptor. You will be a much happier camper.



Please excuse my "piggybacking" your question, can anyone with an informed
opinion weigh-in on this:

http://www.aircraftspruce.com/catalo...nnasystems.php

You put it inside a tube and fabric structure. Seems like a good idea at
first glance...


Read it again. The antenna is meant for composite aircraft or metal tube
aircraft IN A FIBERGLASS WINGTIP. No VHF antenna will work worth a darn
inside of a steel tube fuselage. Google on "Faraday Cage" or "Screen Room"
to get a picture of what is happening.

Jim