[Collins] 75A-3 Filters in a 75A-4

[root]

On Mon, 2005-03-28 at 20:51 -0800, Jim DiMauro wrote:
> Hi All:
> 
> I have a question: are 75A-3 mechanical filters
> electrically interchangeable with those of the 75A-4? 
> I know that they're quite different physically, but if
> they're electrically equivalent I would do a
> reversible mod to install a 6 KHz filter from a 75A-3
> in an 'A-4.  Thoughts?  Facts?  Flames?
> 
> Thanx & 73,
> 
> Jim
> w2bvm
> 
With a few exceptions, most filters for the same frequency, and in
similar sized packages have similar resonated impedances. This should be
reflected in the necessary resonating capacitor sometimes specified in
the data sheets or the impedances. The A3 and A4 filters ought to be
listed in the on-line data booklet on filters. Resonating C is probably
round about 100 pf.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer