After 2.5 years of flawless operation, earlier this summer my YCCC 9 circle rx
array started to develop some strange inter-mod noise, and random junk showed
up on 160m when using the array.
I isolated the problem to be the .1 uF coupling capacitors on the input of the
amps. This happened on 4 of the 9 amplifiers.
The most likely cause is from TX overload because this array is only about 125’
from my parasitic TX array. (the TX antenna is detuned when on RX and presents
no issue on receive).
At first I suspected a nearby lightning strike, but the 4 failed amps happen to
be the closest to the TX array, nothing else in the amp was damaged, and there
was no other evidence of a lightning event at the station.
Here is a link to a YouTube video I made showing how I isolated the problem.
Using my scope I show how the output from the damaged amp has significant phase
and amplitude distortion, and using the multimeter the failed caps are
evaluated.
https://youtu.be/t6oux3MStDw <https://youtu.be/t6oux3MStDw>
If you have one of these arrays, I show how it is very easy to test the
pre-amps in the field using your multi-meter to confirm if a similar fate has
occurred in your system.
73, de steve ve6wz
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