[Elecraft] [K3] Setting RF gain & AGC correctly

[Fred Jensen]

I left all of Bill's post below for context.  Full disclosure - 95% CW

My experience parallels Bill's for much the same reasons.  My K3 [#642] 
has had two EEINIT's, and I haven't changed the AGC settings since the 
second one, 4 or 5 years ago.  The K3 AGC parameters are many and have 
interacting effects.  When playing with them, often I was unable to 
discern a difference between choices, even going very slowly and 
operating for awhile between changes.

I find the APF to be useful with weak signals of course, but also with 
moderate signals in deep QSB ... with APF I don't lose it completely 
even though it went to near ESP levels briefly.  I have spent some 
listening time to SM, LA, OH, and the like during auroral events, with 
rapid, deep QSB, and with AGC off and riding the RF Gain.  Given that 
the propagation under these conditions is essentially a chaotic 
function, I may ... or have just imagined ... a very subtle improvement 
over just running RF at max with AGC on.

I had to max the AF GAIN on my SX-28 and ride the RF of course, now many 
years later, I find the  stock K3 settings to be close to very good for me.

Grizzled Old Engineer advice to an aspiring new engineer [me]:  "The 
fewer the knobs, the less problems from the users."

73,

Fred K6DGW
- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org

On 4/9/2016 4:32 PM, Bill Frantz wrote:
> Note that to change some of the AGC settings you must have Tech MD ON.
>
> I tried these settings and went back to the stock settings. I think the
> reasons were:
>
> I don't run pileups. I am mostly a S&P contester, and always in the
> pileup rather than working it for DX. (Just how many people need Santa
> Clara County CA?), so most of the improvements don't affect me very much.
>
> When I'm listening to weak DX, the higher SLP keeps the occasional
> person who forgets to go into split mode (and the up police) from
> blasting out my eardrums.
>
> My normal background noise on 20M is about S2. (It's about S5 on 160M.)
> I think this means that I'm not getting AGC from the normal background.
> BTW, I don't know why my noise levels are so low living in suburbia. I
> always seem to be a couple of S units weaker than others I hear giving
> honest signal reports. In any case, I have enough sensitivity to get the
> band noise, and I can certainly hear a lot of stations which can't hear me.
>
> When I run digital modes, I don't have to ride the RF gain to keep the
> audio signal to the computer below overload, a nice convenience.
>
> I will have to try turning AGC off when using the Audio Frequency
> Peaking feature. With AGC on, it only seems to do a little compared with
> 50 or 100 HZ on the DSP filter. The DSP filter technique helps suppress
> slightly off frequency strong signals better too.
>
> 73 Bill AE6JV