[ARC5] What the heck is a "1/2 harmonic Q-5er?

[Jim Haynes]

On Sat, 9 May 2020, Bob Groh wrote:

> Just caught K3HVG's recent email in which he mentions wanting a BC-453 or
> R-23 for a "...1/2 harmonic Q-5er for BC-348...". I am certainly familiar
> with using the BC-453 as a tunable IF for other receivers and rather suspect
> this is a variation of that (the BC-348 has, I believe, a 915 kHz IF).  The
> "1/2-harmonic" thingie does intrigue me!!
> 
My friend the late W6NRM, RTTY-er extrordinaire, loved BC-348s in the
1950s.  He had an article published in CQ about the Q-5er he built
for them.  With the dynamotor removed he put a plate in that space
with a couple of mixers and the 85 KHz IF transformers from the BC-453.
He converted 915 KHz down to 85, went through the transformers in
cascade, then converted back to 915 and inserted back into the IF
chain of the '348.

I used his idea in a very much modified BC-348, making the up/down
conversion oscillator tunable from the front panel.  That gives you
passband tuning.

But when the Drake 2-B receiver came out Bob adopted those as his
favorites and quit the BC-348s.

Jim W6JVE