[Premium-Rx] Looking for USB filter for Racal 6790/GM

[Ron Ott]

I'm on my second forey for a crystal USB filter for my Racal 6790/GM. 
 As a result of the first hunt, I bought one LSB and two USB filters, 
but both USB filters have problems.  

In one, there is a 20 db notch in the audio passband about 1 kHz from 
the edge.  I haven't looked at the second filter with an audio spectrum 
analyzer, but it sounded funny also. Is there any strangeness  with the 
Racal auto setup that would give this result? I checked and the BFO 
frequency is spot on (455 kHz, as I recall) and the filter passband is 
right on, except for the funny notch, which is a few hundred Hz wide. 
It's odd, but I suspect a bad crystal in the filter.  The second USB 
filter has been opened and resoldered.

So, if you'd like to part with a good USB filter for the Racal, please 
let me know privately by e-mail. I would consider a USB/LSB filter pair 
if you won't sell the USB separately.

Thanks!!
Ron
W6XY