[Elecraft] K3 - AF/RF Gain [and S-meters]
Guy Olinger K2AV
olinger at bellsouth.net
Thu May 19 20:30:56 EDT 2011
You haven't told us what settings you have on ATT/PRE, per band. That
would make a huge difference in how things worked out. 73, Guy
On Thu, May 19, 2011 at 7:59 PM, Fred Jensen <k6dgw at foothill.net> wrote:
> Lots of good info comes from this list. I segregated all the recent
> "How to set AF and RF Gains" postings to try and see if I'm missing
> something since other than the EQ settings [K9YC's for SSB TX and "try
> to emulate my hearing aid response" for RX], I run pretty much
> out-of-the-box-defaults, AGC on, RF max, AF for volume, and am a really
> happy ham.
>
> In olden days, which have been mentioned here a lot, we ran CW [and SSB
> unless you had a new receiver with a product detector] with AF gain
> firewalled and RF gain for adjustment. The reason for this, although no
> longer valid with a K3, was to equalize the signal and the BFO injection
> amplitudes. Minimum distortion occurred when they were about equal, the
> BFO amplitude was fixed, so you adjusted the signal level through the
> receiver to sort of the same amplitude. The right point was fairly
> obvious. The S-meter followed the RF gain control ... that's just how
> it was.
>
> AGC used to be a somewhat brute force thing ... 1st mixers had to be
> protected so the AGC line hit the RF stage(s) as well as the IF's.
> SX-28? My K3 seems to have an exquisitely designed AGC system [well,
> more than one]. I run with it on, I've tweaked the threshold so it's at
> my normal noise floor, and my RF gain is at max.
>
> I cannot tell any difference between my ability to copy very weak CW
> signals in my normal configuration, and when trying to ride RF gain. In
> light of all the reflector chatter on this subject, I've tried to make
> this work [I'm retired, I have time :-)]. The WIDTH knob can help, the
> APF function can be a big help under some circumstances [not all], and
> very occasionally, the manual NOTCH will make a difference. Other than
> that, it seems letting my K3 do its job by itself, AGC on, RF max, AF
> for volume, works best.
>
> What am I missing here?
>
> For the record, my K3/100 is pretty vanilla: One Rx, "stock" filters,
> KDVR, KAT3. I have several locals within 3km of me, their rigs are very
> quiet on CW, they are the only signals that get much above S9+20, and I
> can get well within 1 KHz of them in contests and still work the weak
> ones. They haven't complained, I hope I'm not getting too close :-) I
> don't operate SSB a lot, usually only in contests to support my contest
> club. If that's what this is all about, I apologize for the BW. If
> it's CW, I'm either missing something or I guess I'm less discriminating
> that most.
>
> 73,
>
> Fred K6DGW
> - Northern California Contest Club
> - CU in the 2011 Cal QSO Party 1-2 Oct 2011
> - www.cqp.org
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