[ARC5] R-26 BFO injection adjustment

[WA5CAB at cs.com]

The R-26 is the only model that has C45.  In the R-25, the diode is open 
(NC).  In the R-27, the diode is tied to ground.

Disabling the AGC for tests would seem to be a simple matter of shorting 
either R5 or C15A to ground.

In a message dated 05/11/2017 21:37:38 PM Central Daylight Time, 
arc5 at mailman.qth.net writes: 
> Well, after some experimentation, i found that C45 on the second diode 
> had the effect of loading the BFO.
> Adding capacitance to the 11 pf made little difference. Removing it helped 
> improve the injection and the ability to 
> 
> beat against strong SSB signals at room volume. It still distorts with 
> very strong signals, but I'd have to turn down the sensitivity anyway.
> I can run the control at 3/4 most of the time now. ( I run a speaker, not 
> headphones).
> 
> 
> I'm still not convinced that the AGC is working properly, but it passed 
> the "ohms to ground test." . It's not that bad that I want  to dive into
> it at this time with live voltage tests. etc, but maybe it will be a good 
> rainy day project.
> 
> 
> 
> Thanks for the insights into this issue.
> 
> 
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
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