[Hammarlund] SP600 - Reduced gain on 13kHz bandwidth

[kirklandb at sympatico.ca]

I have noticed the same thing as Les reported. I have aligned several sp-600's.
I believe the reason is due to how the bandwidths are achieved.
If you look at the schematic you will see that they change the resistances , coil taps 
 as they change bandwidths.  

I suspect that in going to the higher bandwidths the Q is lowered and this creates more loss, 
hence less gain.

As for the response curves, I suspect that they are "normalized".  BTW, I use a spectrum analyzer
 to align the IF's and you do see the dimples on the wider bandwidth.  However you only achieve these
 if you carefully align all of the IF transformers. e.g. It is pretty easy to skew the response if you adjust
 the IF transformer from the RF deck off center a tad.

bill, ve3jhu