Re: PSKMeter (was CU2AP)

Bill Garwood

A few observations.
A couple of years ago when I started with PSK31, I would get an occasional blast from an unknown op that I was a lid and was causing QRM etc.  I have always tried to be courteous and being a bit thin skinned, I quit PSK31 for a while.  Read about the KK7UQ IMD meter and bought it.  My IMD looked good on the meter and I could make it look bad if I tried but in my normal operating parameters, IMD was always -30 dB or better, usually -34 dB.  I was also getting compliments over the air about my nice clean signal but then there was still the occasional complaint.  The complaints were only in the late afternoon and only on 20 meters.  I have seen some of this myself on other stations.  They have a nice signal that seems to suddenly go bad for a short while then improve again.  I've seen it on some of our regular 070 members.  I believe this is some kind of propagation phenomenon.  It seems to be on stations around 500 miles away and must be some kind of NVIS event that maybe has something to do with multipath or something that causes problems with the decoding software at the receiving end.  Station booming in here for a short while at S9+ on the receiver, gets very wide on the waterfall,  then they drop back down to a more normal level in minutes or less.  Probably could work them at that moment with milliwatts of power.
IMD does not always originate at the transmitting station, it can also happen in your receiver.  Try turning the receiver RF gain down or switching in the attenuator and see if the offending station's signal improves on your waterfall.
There are quite a few stations, especially to the south of us, that are not operating properly but I believe most of the US stations are trying to keep their stations clean.
I was using a Signalink with my older rig (TS-680) and played around on a dead band with the adjustments.  ALC always at zero.  I could turn the transmitter power control to full 100 watts and bring the power up to 25 watts with the Signalink and get good IMD readings.  I could also decrease the TX power to 50 watts and bring the Signalink up to 25 watts PSK31 and the values were the same.  -34 dB.  Your results may vary.  Did not notice a sweet spot.
Current rig is a TS-590 and uses USB direct from computer.  ALC at zero.  I can turn the power up on the rig as high as 80 watts and still have a good IMD reading of -30 dB.  I do not operate at that power level except occasionally on 160 meters.
Bill N4GBK  

To: 070@...
From: 070@...
Date: Wed, 11 Feb 2015 10:32:42 -0600
Subject: Re: [070] PSKMeter (was CU2AP)

I found an answer for the software question, where else but
. There is a PSKScope program for XP and
one for Linux to interface the PSKMeter.

I'm still curious if there is a real improvement in IMD and if
the sweet spot is different than the "old" method. I've read
that with some rigs the best IMD isn't always full power with
reduced drive.

Mike kc9doa

On 11 Feb 2015 at 10:08, 'Mike Miller' lists@... [070]

> Hi Milt,
> Couple of questions. How much improvement do you see with the
> PSKMeter over the old method of running the transmit power
> setting at 100% and driving it to 20 or 30% of its rated output
> with no ALC? Will the software run in WINE on a Linux system ?
> I've been running FLDigi on Linux Mint 13 for most of the club
> contests.
> 73
> Mike kc9doa 070#1040
> On 11 Feb 2015 at 3:49, n6mg@... [070] wrote:
> > Jim & others,
> > I use the "PSKMeter".
> > It works, & is very versatile.
> > I have 100 % piece of mind, and a 2nd one as a spare,
> (200%
> > peace of mind! Hi Hi )
> > It's in kit form with all parts available when you order
> it.
> > Under $100.
> > PSKMeter Page
> >
> >
> >
> >
> > PSKMeter Page
> > PSKMeter Page, describing the hardware, software and
> firmware
> > for a monitoring device for PSK31 transceivers that
> > automatically maintains the sound ...
> >
> >
> >
> > View on
> >
> > Preview by Yahoo
> >
> >
> > I'm sorry that our path's didn't cross yesterday. If you
> want
> > to try again today, let me know when and what band.
> > I have a little utility, "Mr Snappy 95" that lets me grab a
> > screen shot, save it and then do as I wish with the file.
> > I used to crop these down on a signal I was in QSO with,
> print
> > it on a matte photo paper, and on the back I ran it through
> the
> > printer with a QSL format. My QSL card to a station was a
> pic
> > of my screen, showing his waterfall signal and all of the
> > details.
> > Milt.
> > N6MG
> > 070-650
> > LONP #76
> > Cheerleader for Clean Signals
> ------------------------------------
> Posted by: "Mike Miller"
> ------------------------------------
> Check out the 070 Club website at
> for the latest information on 070 Club activities.
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