Scott
I set up levels for PSK per this article
http://kc.flex-radio.com/KnowledgebaseArticle50363.aspx?Keywords=PSK
with great success.
It's another method similar what Dudley describe.
To my knowledge, I've never had the type of side bands you describe, but
I have observed differences in transmitted signal depend on where you
are transmitting within the sideband.. The farther away from center
frequency the higher the audio tones being used to modulate the PSK.
There might be an issue if your tones are too high or too low.
You might want to use the "center frequency" feature of DM780 so the
audio tones you use to transmit will also be the same frquencies.
Dave
W0DHB
Dudley Hurry wrote:
Scott,
Besides what Tim asked, have you gone back to another version of SW
or different, maybe MixW, remember that version of HRD is beta,
might have a filtering issue with the Audio filtering...
Another thought, be sure that you are not overdriving in the "Mic"
meter, you should never go over "0" dbm running digital modes. I
usually run with the Drive (RF) at 100 and adjust the TX gain in VAC
to the usual 40 watts or so, this leaves the Mic meter at about -15
to -10 dbm..
But your mileage may vary.. :-)
73,
Dudley
WA5QPZ
Scott Myers wrote:
When I originally set-up my Flex for PSK using DM780, I played with
it with a local ham and we both noted that we each saw sidebands. We
went through all the normal checks with our sound drivers and any and
all the normal checks one would go through with double checking gain
settings in the signal chain. All seemed well, and got no sidebar
comments... until someone had the guts to say something to me today.
I use DM780 with HRD 5.0, VAC and vCom.
Today, someone came back and e-mailed a couple of screenshots of my
PSK31 signal when I was operating at 14.070. Sure enough, a
problem. But these were not the normal sidebars, but rather harmonic
signals about 125 Hz off on either side of my main signal. Then I
had a later QSO, about 1000 Hz higher in the waterfall and the
problem disappeared!!!!
I have noted that sometimes, I do get two bigger harmonic bumps on
either side of the transmitting frequency in PowerSDR which appear
quite close to the transmitting frequency. I can't predict when this
will happen. I tried it again a bit later at the same frequency and
I couldn't recreate this. I will be when I see these larger close in
harmonics, this is when I get the "extra" signals being transmitted
that others can see. I do have the screenshots still.
I have noted that I do see more harmonics on my signal when I am
operating in the lower half of the waterfall when operating on DIGU
or DIGL. (Of course, when I am in DIGL, it looks "reversed" in the
Panadapter as one would expect, since the lower frequencies are
toward the carrier.)
So where is the most likely culprit for these large harmonics that
cause this problem of duplicate signals 125 Hz off; The transmitter
or something in the audio chain? And why do I tend to see more
harmonics when I operate in the lower part of the waterfall closer to
the carrier VS the upper? There may be two different issues. They
may be related. I am at a loss.
Scott AC8DE
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