On 2/6/2011 11:18 AM, JJ Sinclair wrote:
On Feb 6, 11:12 am, wrote:
I understand your point - I saw those suggestions on my L2
instructions, laughed, and pitched it. Why should you pay for
transponder output just to heat up the antenna cable with outdated
RG-58, when low loss LM240 is only $0.70 more per foot? And if RG-58
is bad, RG-174 is 4 times worse...



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- Hide quoted text -

- Show quoted text -

You're right John.................I'll disregard the manufactures
instructions and go with something I heard on ras.............
Yeah, right!

JJ, call AAE and ask about the LM240 cable. It might be their
recommendation was aimed at airplanes carrying 200+ watt transponders
and using shorter cable runs, compared to gliders that might using units
with 150 watts or less and long cable runs. Also, looking at the
transponder manufacturer's recommendation is probably a better
indication of what's needed than the antenna manufacturer. My Becker
instructions made quite a fuss about which cable to use.

Generally, I like to go the "good stuff" for transponders, as
attenuation per foot is much higher at transponder frequencies than our
communication radios frequencies (factor of 8).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)