The little filter ahead of the rest in the 9 MHz IF can be replaced by a
nice, narrow filter as George at INRAD did. It helps some, but it is
not much of a deal as the front end is already designed reasonably well
(there is only so much you can do if you are already in good shape :-).
The "other" rigs with high VHF IF's and wide filters have much more to
gain by a narrow filter up there to protect the next mixer.
Clark
WA3JPG
On Monday, June 16, 2003, at 10:37 AM, Pete Smith wrote:
At 12:11 PM 6/16/03 -0400, you wrote:
The Omni VI first IF is 9 mhz. You have always been able to get narrow
filters there.
Fair enough -- so it's a mystery why a narrow roofing filter *wouldn't*
help, isn't it? A 1-kHz filter there should result in a usefully
better close-in IMD figure, I'd think...
73, Pete N4ZR
The World HF Contest Station Database was updated 9 May 03.
Are you current? www.pvrc.org/wcsd/wcsdsearch.htm
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