[MRCA] BC-348 Help

[DSP3]

Ray,

With appropriate kudos to Joe, WA3EJT et al, one uses 1/2 the BC-348 IF 
frequency and couple it into the mixer of the Q-5er, either ARC-5 or 
SCR-274-N.  Physically, I make an insulated loop, about 1 1/2" in 
diameter and locate it at the base of the 3rd IF in the BC-348.  No 
soldering.  Using RG-175 coax, I run the coax out the back of the 
BC-348.  For convenience, I use either a set of RCA phono M/F connectors 
or a BNC set.  Then, run another length of RG-175 (etc) into the Q-5er 
and connect it to the grid cap of the mixer tube via about 10pf.  
Attaching the signal here effectively bypasses the front end which would 
otherwise serve to attenuate the desired 915 kHz IF frequency of the 
BC-348.  Then, tune the Q-5er to +/- 407.5 kHz to pick-up the IF output 
of the BC-348.  The Q-5er IF tuning rods can be selected for whatever 
bandwidth you desire.  The math for the above is 407.5 kHz + 50 kHz 
(Q-5er IF) X 2 = 915. It works like a charm and the only physical 
connection is the grid cap.  Some say one can get BC-348 IF signal 
leakage via the headphone jack, but that has not been my experience.  
Finally, and if you want to be a bit more elegant, mount an RCA F on the 
rear, top cover of the Q-5er and run the coax to the grid cap. Using a 
submin clip, attach the center conductor to the grid cap.  That way, 
service can be done without difficulty.

Jeep K3HVG


On 2/11/2019 1:06 PM, comcast wrote:
> Jeep how would you set up the Q5 with the BC 348 without hacking into 
> the receiver? how and where would you physically Connect into the 
> IF circuit and how would you run it into the command set receiver?
> thanks Jeff
>
> Sent from my iPhone
>
> On Feb 11, 2019, at 10:08 AM, DSP3 <jeepp at comcast.net 
> <mailto:jeepp at comcast.net>> wrote:
>
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