[Milsurplus] ARR 15, how to narrow selectivity???

[Mike Hanz]

The classic outboard way to solve this problem is with a preselector, 
Mark.  The 4th and 5th editions of the RSGB Radio Communications 
Handbook have some excellent designs that I have used on several of the 
WWII receivers with some success.  It does make band scanning a more 
complex process, but with an in/out switch and some patience, it's not 
bad at all.   Also agree with KK5F that a digital audio processor is an 
excellent additional tool, but nothing beats slicing the unwanted 
interference off at the front end to start with.

73,
Mike  KC4TOS

boeing377 at aol.com wrote:

>My Collins R 105A ARR 15 is now working perfectly including the wonderous electromechanical autotune. It is as broad as a barn door however?and I'd like to narrow it wothout butchering the radio. This rcvr has a variable IF as part of the tuning so a fixed freq xtal or mech filter does not seem useful.? I guess I could make a tunable outboard additional IF stage, but that seems extreme. Any practical ideas?
>