Running here PSDR V 2.2.3 with Flex 5000. The only time I occasionally hear some type of peak distortion or "muddy"-type distortion on 75 meters is when listening to strong AM signals operating "class E" type rigs. I don't hear on it on broadcast AM, commercial SW AM, or amateurs running current transceivers or even most boatanchor rigs. I also don't hear when listening to AM transmissions on 40 or 20 meters. 160 antenna is down so no opinion there.
On 10 meters AM, I generally shun away from being too judgmental on "quality" AM reception, since, besides fading and other atmospheric anomalies, many I've heard and/or worked are not using current state of the art type transceivers, but old drifty boatanchors, converted CB rigs and trashy CB linears, modified commercial rigs, modified commercial FM rigs, or cobbled together old electronic car parts. Maybe, since DTS, EMS, AEX, and myself all live in the Northeast, maybe the AM reception problem, at least on 75, is more localized. Pete, wa2cwa http://www.manualman.com On Wed, 14 Dec 2011 12:48:23 -0500 W1AEX - Rob <w1aex.f...@cox.net> writes: > Which version of PSDR are you using Brett? Version 2.2.3 fixed a very > > big issue with AM reception (AGC tracking the sideband energy rather > > than the carrier energy) that was present in all the previous 2.x.x > > versions and the later 1.x.x versions. That being said, I do notice > what > sounds like peak distortion on some strong signals when using the AM > > mode. I do not hear it when listening with other conventional AM > receivers that I use. Adjusting the AGC-T slider in PSDR doesn't > seem to > stop it, but I wonder if adjusting the variables in the DSP AGC/ALC > > setup tab might address it. The "max gain" and "attack" values might > be > a good starting point for experimentation. Curiously, I never hear > that > distortion with PSDR when listening to strong signals on the AM > broadcast band, so it may have something to do with selective fading > and > the way PSDR deals with it. > > As Tim may have been inferring with his question, the "peak > distortion" > phenomenon is not present on those signals when listening in SAM > mode. > Unfortunately, some of the older AM transmitters being used are not > > perfectly stable and tend to move a few Hz when modulated. The SAM > detector warbles now and then with those stations as it tracks them > on > peaks. It's most notable on 10 meter AM where there's a > multiplication > factor being applied to the VFO in the older transmitters. So, at > this > point, I find that I switch back and forth between AM and SAM to see > > what seems to work best with different stations I run into. I'd be > curious what others may have noticed when operating AM or when SW > listening in the AM or SAM modes. > > 73, > > Rob W1AEX _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
