[R-390] 4kc filter repair?

D. ball [email protected]
Thu, 08 Apr 2004 16:50:54 -0400


Has anyone rebuilt a 4kc filter before? I have been trouble shooting mine 
and have found it to have about a 10s-unit difference on the s-meter and 
about the same drop measured from the IF out using a spectrum analyzer. The 
signal to noise is slightly worse than the others. I have also noticed a 
.5db ripple across the top of the band pass on that filter. I do not notice 
this on the other filters. I also read the same 50ohms across the internal 
coils on all four filters. I supect that the foam inside the filter is bad 
because the filter seems to have a muted tone to it. I have the proper 
re-work tools to dissasemble the filter, clean it, and sweep it on a VNA 
once done. I am wondering if anyone has tried this and if so any tips?
thanks
joe
KE1MB
[email protected]

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