[Elecraft] An AGC story

[Cady, Fred]

Thanks Barry for the suggestion to run some curves while changing the RF
gain position. I've done that and I'm not sure I understand what is
going on yet. Need to think about it a bit. I'll post the curves up on
ke7x.com in a while.
Fred


Fred Cady
fcady at ieee dot org  

> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Barry N1EU
> Sent: Thursday, December 09, 2010 8:11 AM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] An AGC story
> 
> Thanks Don.  I just realized that I can do some quick 
> experiments to get my
> answer using an XG2's s3/s9 capability and noting audio level 
> increase with
> AGC Off and then with AGC On and reducing RF Gain until same 
> audio increase
> is accomplished.
> 
> An aside to KE7X and W4TV:  I too wish we could try 
> experimental firmware
> that significantly raised the max AGC THR value.
> 
> And to K6LL: Yes, I too fear loss of weaker signals
> 
> 73, Barry N1EU
> 
> On Thu, Dec 9, 2010 at 3:00 PM, Don Wilhelm 
> <w3fpr at embarqmail.com> wrote:
> 
> >  Barry,
> >
> > Without doing any measurements it may be difficult to say 
> precisely, and I
> > would think there would be a bit of difference from one K3 
> to another.
> >
> > However, there is a quick and easy way to accomplish that - 
> note that the
> > S-meter increases as the RF gain is reduced.  So if you 
> want to increase the
> > AGC Threshold by (say) 3 S-units, disconnect the antenna, 
> and reduce the RF
> > Gain until you move the no-signal S-meter up by 3 S-units.  
> That should be
> > close to your goal.
> >
> > 73,
> > Don W3FPR
> >
> > On 12/9/2010 9:07 AM, Barry N1EU wrote:
> >
> >>
> >> Cady, Fred wrote:
> >>
> >>> I made some measurements and have posted the results for 
> your perusal
> >>> and information at www.ke7x.com.
> >>>
> >> Very interested findings -  Fred has a graph of AGC action 
> with AGC THR=8
> >> labeled figure 3 on http://www.ke7x.com/home/the-k3-agc-story  :
> >>
> >> So I ask this group: is it possible to raise the AGC 
> Threshold from s3 to
> >> s6
> >> or s9 by simply reducing the RF Gain control?  Can anybody 
> estimate what
> >> settings of the RF Gain control would accomplish that?
> >>
> >> Barry N1EU
> >>
> >>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>