[R-390] Filter Repair

[quartz55]

Great.  The 8K filter is working, however, it turns out to be more like a 9K filter.  No biggie.  Only other thing is it only appears to have 8dB loss in the passband range.  All the other filters I've worked on (only 2 and 4 K filters) have had losses in the 25dB range.  Is this typical?  I know the spec is no more than 26 dB I think.  Here's a plot of the thing with my test setup. http://i251.photobucket.com/albums/gg287/DogTi/R390A/8K6723_zps80cfb0b2.jpg  I put a line in at -14 dB (6dB down).  My setup is still limited to about 45-50 dB range.

I've learned a lot fixing this one, kind of getting the patter down.  I don't know whether to go ahead and fix the 16K while I have things apart, which appears to have about 350 Meg to ground resistance.  I'm sure the foam has turned to glue like the rest.  I can't even measure the resistance to ground on the 8K one now, so it must be beyond 500 Meg.  That's quite an improvement from 20 Meg or so.

Dave
N3DT