[ARC5] BC-348 Question

[D. Platt]

Its the age-old problem of lack of proper BFO injection.  The BFO was 
designed to create a beat note for copying CW, not for recoupment of a 
suppressed carrier.  The ratio required for each is quite different. 
That is, for CW copy, not much injection is required.  For copying SSB, 
BFO injection of upwards about 25-50% of the amplitude of the received 
signal (at the point of BFO mixing) is required.  That's what a product 
detector does. Using MVC (no AVC), one can adjust the gain such that the 
ratio fairly correct.  I've had some success by increasing the BFO 
injection in older gear, but only limited.

Jeep - K3HVG


On 5/3/2013 9:44 AM, Robert Eleazer wrote:
> I have been enjoying listening to an BC-348-N of late and found something interesting.
>
> When on AVC the BFO sometimes does not seem to be strong enough to resolve SSB.  Is especially obvious on 80M.  For the weaker signals, you can pick out SSB Okay, and on the higher bands it works better.  Now on MVC it all works Okay, on all bands; you can get SSB fine.
>
> Previously I had a problem with the BFO on this same receiver and "eventually" replaced the associated tube, which fixed it.
>
> Anybody have an idea what is going on?
>
> Thanks,
>
> Wayne
>
>