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

[Hubert Miller]

If you want the BC-453 to pick up the 915 kHz IF from the BC-348,
the Q5er has to be tuned to ( 457.5  kHz - 85 kHz )  = 372.5 kHz, right ? 
Then I would think, loop around the BC-348 last IF run to loop around the
BC-453 (glass ) mixer tube. No ? I have not tried this.

I recall the first "Q5er" article I saw was in a Radio - TV Experimenter magazine from
the mid 1950s. It was by the well known DXer columnist C. M. Stansbury, as I recall.
The article was titled "The Secret Weapon" and he used an RAX - LF receiver. I recall
I wrote him a score years later and asked if he cared to sell the receiver. Pretty naïve
on my part, but I was younger and ( more ) callow then.
-Hue Miller 

-----Original Message-----
From: arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> On Behalf Of Kenneth G. Gordon
Sent: Saturday, May 9, 2020 10:22 AM
To: ARC-5 Maillist <arc5 at mailman.qth.net>
Subject: Re: [ARC5] What the heck is a "1/2 harmonic Q-5er?

On 9 May 2020 at 11:09, Doran Platt wrote:

> 
> Bob,
> Yes, the concept was written up in ER magazine by Joe, WA3EJT.  I 
> simply loop couple the Q-5er to the last IF of the BC-348 and tune the 
> LF receiver to 1/2 the IF of the BC-348 minus 50 kHz.  I adjust the 
> variable IF cans in the LF receiver to about 1/2 down and all works 
> really well.  The BC-348 becomes entirely usable in crowded 
> conditions.
> Jeep K3HVG

Yes. Exactly. Turns out that the IF output of most receivers has a good harmonic output and tuning the BC-453 or R-23 to 1/2 the frequency of the IF (915/2=457), the Q-5er "hears" that just fine and works just like it does with a receiver which has a 455 kc IF.

I have that article here somewhere. I have forgotten the year and number of ER in which it appears.

Joe Long went into quite a lot of detail on this process, and tried it with several different receivers which had IFs other than 455 kc. It worked perfectly in all cases he tried.

Ken W7EKB
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