[Elecraft] IF xtal replacement mod

[Vic Rosenthal]

"David A. Belsley" wrote:
> 
> Well, I replaced the 7 IF xtals and redid CAL FIL with spectrum analyzer.
> I guess the results are good, although I didn't do any before and after
> measurements.  The only negative is that my FL4 position, at 100Hz, is now
> much more attenuated relative to the other BPs, roughly one S unit.  It was
> somewhat less than the others before the mod, but not that much.  Any
> thoughts out there?

I found (in my case, both before and after replacing the crystals) that the
attenuation increased sharply when the filter width was less than about 200 Hz,
and that the actual bandwidth as viewed on spectrogram did not appear to narrow
so much.  So I settled on 220 Hz as my narrowest filter.  Incidentally, I used
220 rather than 200 because at this bandwidth the pitch of the signal centered
in this filter did not vary from the others.

73
Vic K2VCO