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Old February 6th 11, 06:27 PM posted to rec.aviation.soaring
JJ Sinclair[_2_]
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Default Transponder antenna installations

On Feb 6, 9:57*am, jcarlyle wrote:
JJ, please don't use RG-58 for a transponder cable - it has very high
attenuation per foot. Times Microwave LM240 is a much better choice,
with only 1/3 of the attenuation of RG-58 at 1 GHz. I usually use
Times Microwave LM300, with only 1/4 the attenuation of RG-58, but it
has double the diameter. Both of these cables have a greater than 20
year life outdoors.

-john

On Feb 6, 9:07 am, JJ Sinclair wrote:



I second the L-2, di-pole antenna suggestion, all inside with nothing
sticking out to get ripped off. Carve a1"X 1"X4" balsawood block so
that it matches the inside curve of your non-carbon fuselage, then
glue the antenna vertical to the flat side and the curved side to the
inside aft fuselage. *Keep it about 6" away from metal objects like
your elevator push-rod, etc. Secure the RG-58 lead so that it can't
get tangled with controls and you're good to go.
Hope this helps,
JJ- Hide quoted text -


- Show quoted text -


The instructions from Advanced Aircraft Electronics call for RG-58A/U
unless wire bundle size is critical where the smaller RG-174/U may be
used if length is held to 20 feet or less.
JJ