KX3 AGC FD Issues and AGC Settings

[Ed G-2]

Hi Folks,
     I thought I might see a few more e-mails on the KX3 AGC pumping issue
briefly talked about earlier, especially with some Field Day conditions in
the mix.  I used my KX3 at home, so was not real near any active stations,
but still noticed some thumping with stronger signals.  I kept switching
over to the K3 which made me especially aware of the KX3 problem as the AGC
issue does not exist on my K3.
     I do see the "placeholder" MENU setting for the KX3, which looks like a
way to set five different AGC parameters when it's activated in software.
The manual says "details pending."  I'm hoping the ability to set these
parameters will get rid of the somewhat annoying thumping.  Any other KX3
users notice AGC issues during FD?
--Ed--


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[wayne burdick]

Hi Ed,

I know of no other such reports. The latest KX3 firmware has very well-
behaved AGC. We're getting close to a new field-test release that I  
could send you.

The present noise blanker may be susceptible to pumping from nearby  
signals and it, too, is due for an upgrade. Also, the roofing filters  
should help if they're installed and you have the PBT control set for  
a narrow width.

The AGC*THR entry provides access to several AGC parameters, each of  
which starts with AGC*. For most purposes the defaults will suffice.  
Tap the 1 through 6 switches to access the following parameters  
(defaults in parentheses):

1 AGC*THR (007): Threshold at which AGC action begins. A higher number  
moves the threshold up, providing greater audio dynamic range.

2 AGC*ATK (215): Rate of AGC attack. A lower number than the default  
provides a softer attack but may also result in overshoot.

3 AGC*HLD (000): Hold time in seconds for voice modes. Prevents AGC  
decay for a specified time after attack, reducing AGC interaction with  
signals.

4 AGC*DCY (Fast, 140; Slow, 040): Specifies the decay rate for slow or  
fast AGC (see AGC SPD menu entry). A larger number means a faster decay.

5 AGC*SLP (015): The higher the slope number, the "flatter" the AGC  
response is. With a high setting of slope, signals above the AGC  
threshold will be held close in audio amplitude even if they vary in  
strength at the RF input.

6 AGC*PLS (NOR): Noise pulse rejection. Prevents the AGC (and S-meter)  
from charging up on one-shot noise events. Set it to OFF to disable  
this feature.

73,
Wayne
N6KR


On Jun 25, 2012, at 4:12 PM, Ed G wrote:

> Hi Folks,
>     I thought I might see a few more e-mails on the KX3 AGC pumping  
> issue
> briefly talked about earlier, especially with some Field Day  
> conditions in
> the mix.  I used my KX3 at home, so was not real near any active  
> stations,
> but still noticed some thumping with stronger signals.  I kept  
> switching
> over to the K3 which made me especially aware of the KX3 problem as  
> the AGC
> issue does not exist on my K3.
>     I do see the "placeholder" MENU setting for the KX3, which looks  
> like a
> way to set five different AGC parameters when it's activated in  
> software.
> The manual says "details pending."  I'm hoping the ability to set  
> these
> parameters will get rid of the somewhat annoying thumping.  Any  
> other KX3
> users notice AGC issues during FD?
> --Ed--
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

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