Phil, It is quite normal for the S-meter reading to increase when the RF gain is reduced. The AGC voltage (which drives the S-meter) is increased to reduce the gain of the receiver when the RF Gain is reduced - so the S-meter indication goes up.
The way I tend to think of it is - there is already an S-3 level of atmospheric (and locally generated) noise on a particular band, so I reduce the RF Gain until the S-meter reads S-3 and the band noise does not bother me. Signals stronger than the band noise will still make the S-meter increase, so I can still see a relative signal strength reading between stations. If you want to reduce the signal level into the K3 without changing the S-meter, set the menu to S-MTR ABS (S-meter absolute) and turn off the preamp and possibly turn on the Attenuator. In ABS mode, the S-meter will not change with preamp or attenuator on/off, but it will still rise with reduction of the RF Gain. For maximum performance on any particular band, if you can hear the band noise (with no signal present), turn the preamp off (it is not needed and is detrimental to the receiver dynamic range) - if the band noise is still present, turn on the attenuator. If you can still hear the band noise, reduce the RF gain to the point where the band noise is just barely audible - that is the maximum sensitivity setting that can be used for that band. Note than this optimum setting will change from time to time, and from band to band. The K3 has more than ample gain so it can hear very weak signals - if the band noise is high, you are unlikely to hear signals below that band noise level, so it is wise to reduce the receiver gain to keep the receiver from sounding "noisy". This is different than squelch. Squelch totally silences (mutes) the receiver until a signal greater than the level set by the squelch control is exceeded. Does that help? 73, Don W3FPR Phil Hystad wrote: > I have never really understood the connection between RF gain and squelch > controls. I first saw this when I got my first modern rig, the Icom 756 Pro > III. And, I see this kind of combo with the K3 too. I never had experience > with this back in my early ham operator days (~1960s). > > So, can someone explain the behavior. Let's assume that I have squelch > operative for FM only. > > On CW or SSB I see that RF gain maximized is the control knob turned all the > way clockwise. But, as I back off the RF gain (counterclockwise) there comes > a point where the S-meter starts to increase even though there is no apparent > signal. Turning the RF gain fully counter clockwise pins the S-meter. > > So, what is going on here. What is this connection between turning "down" RF > gain and the S-meter increasing. Now, I have the same behavior (roughly) on > my Icom Pro III and I never understood that either. > > Thanks for any explanation you can contribute. > > 73, phil, K7PEH > K3 owner for one full week now. > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
