[TenTec] Ten Tec OII - SSB Distortion

[Dr. Gerald N. Johnson]

On Tue, 2009-01-13 at 20:56 +0000, ac9s at mchsi.com wrote:
<SNIP>
> >----- Original Message ----- 
> >From: "Mark DeBord " <markinkpt at hotmail.com>
> >To: <tentec at contesting.com>
> >Sent: Monday, January 12, 2009 9:51 AM
> >Subject: Re: [TenTec] O2 - SSB distortion
> 
> 
> > Check the mic gain. The Orions, Omni VII, and Jupiter will overdrive and 
> > it sounds exactly like RF. Your ALC should only flicker on some words. 
> > Check the menu to make sure the menu mic boost was not accidentally 
> > increased.
> >
> > Mark ka4ick
> 
> As originally reported, I have been experiencing really distorted SSB with my OII for the last 3 - 4 weeks - after receiving glowing reports for the last 2 years.  I have partially 'cured it', but don't have the root cause nailed yet.  A master reset will restore the radio to its excellent state, but it appears my problem reappears after checking into a 160 meter AM net we have locally on Sunday mornings.   160 Meter AM operation is always distorted and once I have operated 160 I then have the problem on all other bands with SSB.  A master reset now gets me back in operation, but I don't know what is triggering the problem.   This Sunday I used  my 756Pro and received excellent audio reports on the net.  I switched to the Orion and had the distorted report.  Asked the guys to switch mode, did a master reset and had excellent audio reports on SSB, which I then validated on 40 and 20..  So - it looks like AM operation on 160.  Maybe There is enough RF floating around the sha!
 ck 
>  on 160 o scramble its little brain, but I have always thought the Pro more succeptable to RF than the O2 and I don't have any evidence of RF in the shack.  
> 
> Does this trigger any thoughts?  I can work around the problem, but clearly something is wrong. 
> 
> Thanks --
> 
> Keith
> AC9S

Maybe its going to AM that raises the gain and it doesn't go back when changing 
to SSB. Try going to AM on another band, today on 10m you probably won't be noticed.

Then try going to 160 AM on a dummy load. That will keep RF out of the
microphone input. Does it have the microphone connector grounding mod?

73, Jerry, K0CQ