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Old January 1st 18, 01:22 AM posted to rec.aviation.soaring
Scott Williams
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Posts: 198
Default ASW27 Trasponder Antenna Installation Inside Fuselage.

On Sunday, December 31, 2017 at 7:12:51 PM UTC-6, Scott Williams wrote:
On Sunday, December 31, 2017 at 6:13:39 PM UTC-6, Steve Koerner wrote:
On Sunday, December 31, 2017 at 3:13:42 PM UTC-7, Dan Marotta wrote:
If it's not too much trouble, try a coax cable length of 21 11/16 inches
which would be 2 wavelengths at 1090 MHz (assuming my arithmetic is
correct).Â* You may have reflected power in your coax which will reduce
performance.


Dan: I'm not jumping into the real technical matters here but its pretty obvious that you're neglecting the fact that waves travel slower in coax.


Hey Dan,
I think you may be correct about Too short,
I googled this and there is a couple of opinions that seem to originate
with Garmin, I doubt very many transponders are installed with coax runs
less than 15 inches, maybe this particular problem is rare?
I'm using rg400, and may try a longer coax run.
Thanks,
Scott.


In addition,
So does anyone willing to suggest a coax length if not 21 11/16 inches?
maybe tree foot? is there a non critical length range?
Scott.