[Hammarlund] HQ129X AVC

[Carl]

It sounds as if the radio needs a full recap, the original paper caps 
are leaky. This affects the AVC circuit by acting as a voltage load so 
the tubes can get full AVC voltage.

It could also be a tube on the AVC line that has cathode-grid leakage 
which keeps the control grid biased at full on.

Another possibility would be modifications that werent done correctly.

I had a HQ-129X with a DX-100 and then a Viking I in the late 50's. I 
now have another 129X and Viking I.

Carl
KM1H


----- Original Message ----- 
From: "Guido Santacana" <laffitte at prtc.net>
To: "D C *Mac* Macdonald" <k2gkk at hotmail.com>
Cc: <hammarlund at mailman.qth.net>
Sent: Wednesday, September 10, 2008 8:27 PM
Subject: Re: [Hammarlund] HQ129X AVC


> Hi Mac,
>
>  This is happening in the AM mode until the HQ is on for about 60 min. 
> At the beginning it is as if the AVC is nonexistent.
> I had an HQ170AC matched to a Heathkit DX100B years ago. It was great 
> and I have always regretted getting rid of them.
>
> 73s
> Guido KP4FAR
> ----- Original Message ----- 
> From: "D C *Mac* Macdonald" <k2gkk at hotmail.com>
> To: "Guido Santacana" <laffitte at prtc.net>; 
> <hammarlund at mailman.qth.net>
> Sent: Wednesday, September 10, 2008 9:16 PM
> Subject: RE: [Hammarlund] HQ129X AVC
>
>
>
> Hello, Guido!
>
> The AVC/AGC on an unmodified HQ-129 works ONLY in the
> AM mode of operation.  CW or SSB modes require you to
> back down the RF gain and run the AF gain fully advanced
> unless you add a product detector and fast-attack and
> slow decay AGC circuit.
>
> I converted the HQ-145X I owned many years ago (1962 to
> 1966) for CW/SSB with a product detector and AGC circuit
> I stole from my National NCX-3 transceiver.  It made a very
> good match for the Hammarlund HX-50 transmitter I had then.
>
>
> 73 - Mac, K2GKK/5
> Oklahoma City, OK
>
>> From: laffitte at prtc.net> To: hammarlund at mailman.qth.net> Date: Wed, 
>> 10 Sep 2008 21:09:14 -0300> Subject: [Hammarlund] HQ129X AVC> > Lets 
>> see if the combined wisdom of this list can help me out on this.> My 
>> HQ129X overloads on strong signals with the AVC on. This will last 
>> until the radio has warmed up for quite a while. Then the AVC starts 
>> to work normally. HQ129Xs suffer from overload or at least I have 
>> heard that. Opinions will be most wellcome.> > 73s> Guido Santacana 
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