Hi Douglas
A few posts ago, in a long meandering thread, I made an assertion that Racal introduced a mod to replace the spring edged covers with knitted mesh versions. You said you'd never seen any.
It took a while to scan through the various RA17 documents I have. But here it is:
E729 Misc Instr No 9
...RA17L
...Change of filter covers
"In order to reduce spurious oscillation below specification figures...change the covers of the 37.5MHz and 40MHz filters...new covers contain "knitmesh" cushions, and will replace existing type covers in future equipment manufacture."
There is then a list of existing spring finger part numbers and the corresponding modified knitmesh part numbers.
Dated Jan 1971.
It may be possible to get the same effect by taping the filter seams with adhesive copper EMC tape (once the filters are aligned of course!).
Craig
