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Harsh Sidetone on QCX-20M With AGC On

Ernie Bailey - N2DGQ
 

I have read several topics about this on this forum regarding harsh sidetone and relating to RF feeding back to speaker.  But in my case when I turn the AGC off the harsh side tone goes away.  I have a QCX-40M rig with AGC and there is no harsh sidetone.  I am using a powered speaker. And I have a Rev-3 rig. 

I have removed the AGC board and reinstalled it.  Adjustment of the AGC potentiometer does not seem to remove the harsh side tone.  

It's not the end of the world as there does not seem to be as many strong signals on 20M as there is on 40M.  But I'd like to have the AGC on.  

Any suggestions? 
Tony AE0KW <tcollen@...>
 

Check your sidetone volume setting in the menu. I had my QCX for 2 years before I realized it existed, and it turned out it was set to the maximum value. Dialing it down to maybe 15 or 20 (out of a max of 99 or 100 or whatever) cleaned up my sidetone quite a bit.


Tony AE0KW

On Sun, Apr 3, 2022 at 10:53 AM, Ernie Bailey - N2DGQ wrote:


I have read several topics about this on this forum regarding harsh sidetone
and relating to RF feeding back to speaker.  But in my case when I turn the
AGC off the harsh side tone goes away.  I have a QCX-40M rig with AGC and
there is no harsh sidetone.  I am using a powered speaker. And I have a Rev-3
rig.

I have removed the AGC board and reinstalled it.  Adjustment of the AGC
potentiometer does not seem to remove the harsh side tone.

It's not the end of the world as there does not seem to be as many strong
signals on 20M as there is on 40M.  But I'd like to have the AGC on.

Any suggestions?
Ernie Bailey - N2DGQ
 

Thanks Tony.  My volume is set to 17.  Just for kicks I tried setting it to 7, and still had the same result. 
mike/w1mt
 

How does it behave with a dummy load?

-mike/w1mt
Ernie Bailey - N2DGQ
 

With a dummy load on it sounds normal.  I would suspect a common mode issue on the antenna leads but my QCX-40M rig sounds normal with the AGC on.  My main rig is a Yasue FT-450D and there is no issues with common mode currents there.  
mike/w1mt
 

If it's fine with a dummy load then, yes, it's a common mode issue. Describe your antenna and feedline to the rig.

-mike/w1mt
Chuck Braswell
 

Add a .01uf cap between pins 1 and 2 on earphone socket pins on back of board. Make sure it lays flat to clear case. Takes care of the stray RF issues in the audio.


On Sun, Apr 3, 2022, 18:25 Ernie Bailey - N2DGQ <ebrcdddcdc@...> wrote:
With a dummy load on it sounds normal.  I would suspect a common mode issue on the antenna leads but my QCX-40M rig sounds normal with the AGC on.  My main rig is a Yasue FT-450D and there is no issues with common mode currents there.  

Ernie Bailey - N2DGQ
 

Mike, I have RG-213U feeding an OCF Dipole up about 25-Ft.  The feed line goes into a lighting arrestor then to my LDG YT-1200 Automatic Antenna Tuner.  From the tuner I feed a one-meter piece of RG-8X to the QCX for 20M.  I have the same set up for my QCX-mini on 40M and there is no issues with harsh side tone.  
Ernie Bailey - N2DGQ
 

Chuck, I'll check that out ant let you know what happens. Thanks for your suggestion. 
mike/w1mt
 

Different bands on the same antenna system will behave differently. I would try putting a choke between the RG-213 and OCF dipole. You could try one closer to the rig for convenience just to see if it works. I've found that a properly designed choke can keep common mode away from the rig.

-mike/w1mt


On Tue, Apr 5, 2022 at 8:52 PM Ernie Bailey - N2DGQ <ebrcdddcdc@...> wrote:
Mike, I have RG-213U feeding an OCF Dipole up about 25-Ft.  The feed line goes into a lighting arrestor then to my LDG YT-1200 Automatic Antenna Tuner.  From the tuner I feed a one-meter piece of RG-8X to the QCX for 20M.  I have the same set up for my QCX-mini on 40M and there is no issues with harsh side tone.  

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