Thanks Don. No, I wouldn't want all sigs to have the same audio level. I'll play with AGC off, and the limiter, and the AGC settings.
Mike On 11/6/2010 9:20 PM, Don Wilhelm wrote: > Mike, > > The AGC works at the IF level, not the audio level. > What that means is if you crank the AF gain way up to listen to a very weak > signal, > AGC action is probably not even started because the signal level is at or > near the > level of the band noise - In other words, the receiver is operation at "full > gain, > all stops removed". > > Under those conditions, if a very strong signal suddenly comes into your > passband, > yes, it will be loud simply because the AF Gain is advanced. Yes, the AGC > will > respond to that new signal - just how much depends on how you have the AGC > menu > parameters set. If it does cause an AGC response, it will reduce the gain of > the > receiver, and you will no longer be able to copy the signal at or near the > band > noise floor. > > So perhaps what I am saying is that everyone might run their AGC parameters > so that > all stations, no matter what their relative strengths will have the same > audio > level - that would cure the condition you have stated - but I do not really > believe > that is a good solution - for one, it will make band noise the same audio > level as > the signals - result is "noisy K3", and we have been there before. > > Myself, I prefer to be able to determine the relative strength of various > signals > "by ear" rather than "by S-meter" - that means the strong signals will have > greater > audio levels than weaker stations - that is just the way it is. > > Since very weak signals (which is what APF is all about) are well below the > level > that AGC action starts, when trying to dig out such a weak station, it may be > wise > to turn off AGC altogether (provided you have set the AF limiter beforehand). > With > AGC off, the Audio limiter is active to protect you from ear-shattering > events such > as a strong signal suddenly coming on frequency. > > An additional benefit to copying very weak signals with AGC off is that a > strong > signal coming on within the passband will not de-sense the receiver (as it > would > with AGC on), so you may be able to use the "filter between the ears" to > continue > copying the weak signal. > > 73, > Don W3FPR > > On 11/6/2010 7:46 PM, Mike wrote: >> Thanks Tom. >> >> Well, I kinda thought it shouldn't blast my ears that hard. Audio *WASN'T* >> up too >> loud for the signal I was after. Maybe I don't understand what AGC does. >> That's why I >> asked the questions I did. >> >> On 11/6/2010 6:21 PM, Amateur Radio Operator N5GE wrote: >>> On Sat, 06 Nov 2010 18:04:18 -0400, Mike<[email protected]> wrote: >>> >>> Sounds normal to me. >>> >>> Audio up too loud and APF on, then a strong signal transmits on the >>> frequency >>> you are listening to.... >>> >>> What do you think it SHOULD have done? You didn't say. >>> >>> Tom >>> Radio Amateur N5GE >>> >>>> On 11/4/2010 9:48 PM, Mike wrote: >>>>> I'm playing with the new APF, and trying to get a REALLY weak QSO to pop. >>>>> I >>>>> have the >>>>> volume cranked up pretty good, and a REALLY strong station throws in >>>>> their call. I >>>>> thought my speakers had blown. Glad I wasn't wearing cans. >>>>> >>>>> My CONFIG:AF is 18, AGC = F. >>>>> >>>>> Was I doing something wrong? Anybody else experience this? Do we need/can >>>>> we have >>>>> better audio limiting? >>>>> >>>>> 73, Mike NF4L >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
