Transponder antenna installations

On Feb 7, 7:46*am, Willy VINKEN wrote:
On Mon, 7 Feb 2011 06:18:57 -0800 (PST), JJ Sinclair





wrote:
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 Becker 4401-175 manual does say that RG-223/U is preferred over
RGU-58, but it doesn't mention LM-240? As a mechanic I am bound to
follow the appropriate tech data. Does LM-240 use the same BNC
fittings I have in stock? Can I use my crimper? What would my log book
entry say? Installed Becker 4401-175 transponder in accordance with
opinions found on ras?
:) JJ

*'Aircell 5' *is a good substitute for plain vanilla RG 58/U coax
cable.
It fits standard BNC connectors.
Attenuation at 1000 MHz is about 32 dB/100m (compared to 54 for RG58)

Willy VINKEN *-ON5WV-- Hide quoted text -

- Show quoted text -

....and Aircell 5 IS listed in the manual for the Trig transponders.
RG-58 is not.