Hi Ira,
Being that RF is my specialty, I would suspect that the folks having trouble
with GPS reception with the antenna mounted in the panel are likely caused by
the proximity to metal parts to the antenna or a leaky coax connector.
Grounded metal parts, i.e., radio chasis, wiring, etc, would "desense" the
receive characteristics of the antenna if they are close enough by changing
the characteristics of the SWR of the receive antenna. GPS signals are weak
and it doesn't take much to make the signal unusable. A leaky coax connector
close by on your Com or Transponder wouldn't help matters either.
Regards,
John Lawton
Dunlap, TN
A-245
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