[Hammarlund] HQ-180 AVC and Audio Issues

[Bob Camp]

Hi

> On Dec 18, 2014, at 6:10 PM, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:
> 
> Thank you for the information, Byron, especially on what you did to yours.
> 
> I have a complete collection of HSN, which I bought some time ago. I'll dig 
> into them.
> 
> BTW, one thing about the Hammarlund receivers that has always bugged 
> me is their continued use of the 6C4 as their HFO.

Simple answer - lower phase noise.

Bob
> 
> I've never understood why Hammarlund insisted on using that tube, or an 
> earlier type, in the HFO. Triodes are too easily pulled by adjusting the RF 
> gain, and voltage-regulating the HFO voltages does not always fix the 
> problem either.
> 
> It isn't all that difficult to change that circuit from a triode to an 
> electron-coupled pentode circuit using a 6AH6WA, and that makes a big 
> difference in the stability of the HFO.
> 
> Ken W7EKB
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