[ARC5] Question on IF transformers...

[Kenneth G. Gordon]

OK, Gang, this question is for those smarter than me (which shouldn't be all 
that hard): 

Why are connections to the 1st IF transformers in the receivers up through 
the 1.5 - 3.0 MHz receivers NOT tapped down on the IF coil, while the 2nd 
and 3rd IF transformers ARE tapped?

In the 3.0 to 6.0 Mhz receivers, the 1st and 2nd are NOT tapped, while the 
3rd MAY be tapped, and in the 6.0 to 9.1 MHz receivers, NONE are tapped.

Yet one can substitute a tapped-coil IF can for the un-tapped ones and there 
appears to be no difference in operation.

In my (somewhat limited) experience, one taps down on a coil in order to 
match impedances better AND to "unload" the coil, making the circuit a bit 
more selective.

If that is the case here, why would the ARC engineers want the 1st IF stage 
to be less selective than the other two, or is there some other reason for this 
difference?

Will someone please explain this apparent anomally?

This is really bugging me....but then again, sometimes I "bug" easily.

Ken W7EKB