[AMRadio] Re: GB> 75A-2 project (sbjohnston@aol.com)


D. Chester k4kyv at charter.net
Wed Jan 23 21:42:58 EST 2008


> It might be possible to "stagger tune" the IF stages to increase
> bandwidth.  Use of a sweep generator (or a manually swept signal
> generator) will let you know how you are doing when trying this.  As a
> general rule, you can trade gain and selectivity for increased
> bandwidth.  You might be able to get as much as a doubling of the IF
> bandwidth by this method.


Another approach might be to try overcoupling one or more of the i.f. 
transformers.  This might be accomplished by physically moving the primary 
and secondary coils closer to each other, if their mechanical configuration 
permits.  Overcoupled tuned circuits tend to have a broader bandwidth with a 
dip in the middle of the passband.  Combine this with a more loosely coupled 
stage with a narrower peak that coincides with the dip, and the sum result 
would be a broader and flatter passband with steeper skirts.

Don k4kyv 



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