[R-390] Stagger-tuned IF question

[Mark Huss]

In the first run from Collins, all the I.F. cans were peaked at 455 
kHz.  Turned out, though, that the Q was a bit too sharp for the 16 kHz 
bandwidth, so all subsequent runs are stagger-tuned.  This includes the 
first-run models as soon as they hit Maintenance.  If you tune it 
straght, you will get higher gain and a bit less noise at the detector, 
but the 16 kHz position will roll off about 10-12 kHz.  Then you will 
have to turn the GAIN pot on the I.F. deck down a bit, which will reduce 
noise a bit more.  Don't know what you would gain by doing this, though, 
except a slightly lower noise floor.

Barry wrote:

>Guys,
>
>In the alignment instructions in my R390A manual, it states that some I/Fs
>should be stagger tuned while others should be straight through at 455kc,
>but it doesn't explain what determines this.  Is there a component
>difference that makes this distinction or is it simply the application for
>which the receiver is to be used?
>
>I'm thinking a CW-only receiver might benefit from being tuned at 455kc
>while a receiver that was going to do a lot of voice work might sound better
>stagger tuned.
>
>What's the skinny on this?
>
>Thanks,
>
>Barry - N4BUQ
>
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