One of the local UHF repeaters had a jumper center pin desense problem, but that was with the opposite condition where below a certain temperature the center pin pulled apart more. I do not remember if there was noted to be change in antenna feedline SWR when the crackles? occurred in the current situation, but like with a scratchy stationmaster, if the weak internal antenna connection is far enough up in the collinear elements, the SWR could be normal. I am thinking internal antenna problem because temperature increase is a factor and wind does not create? more crackles.
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John
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On 01/08/2025 6:49 PM EST DCFluX via groups.io <dcflux@...> wrote:
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Next guess would be the Center pin of the connector is sunken in just enough to be a problem.
After heating with a heat gun and cooling with freeze spray,
everything in the rack (and also bypassing the diplexer), nothing
made a difference in the appearance (and disappearance) of the
crackles other than transmitter ON time.
Looking at the output of the PA with an SA doesn't show anything out
of the ordinary either. And (I think I posted this before), the TX
time to warm things up can come from either the UHF or VHF repeater,
would seem to point to either the antenna and/or feedline and their
connections.
As the UHF side of things never has cracklies, I feel I can rule out
the feedline and various connectors and pin it down to the antenna.
Is my logic flawed?
Ken
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