As far as I can tell, the sound card is the limiting factor in
receive IMD generation when using a K3, KX3 or K2. I try to run
my receive just below where the computer software indicates the
digital levels are distorting, and control that level with the
RF gain control. This procedure seems to keep all the radio
pieces within their linear range. I can see IMD being generated
on my waterfall when I have the RF gain too high, and it is all
in my receive chain.
Measuring IMD on a PSK signal is not as easy as it seems. Any
band noise may be interpreted as IMD, so the weaker the signal,
the worse the IMD reading. Ideally IMD measurements will be
taken with a strong signal and without any data -- so you just
have the PSK idle "railroad tracks". I just ignore IMD
measurements from stations I am only receiving weakly, assuming
they are also receiving me weakly. From strong stations, I get
good reports.
As for obnoxious, rude reports; they aren't limited to PSK. I
answered a CQ on 80M SSB running QRP and the ham at the other
end just said, "Get an amp!" A signal report and a comment that
I was too weak to continue the conversation would seem to be the
least one should expect. I'll just try to remember not to behave
rudely myself.
Cheers - Bill, AE6JV
On 6/26/13 at 11:45 PM, [email protected] (Mark Petiford) wrote:
I am relatively new to PSK (operate mainly CW), but after
receiving my KX3, started to take an interest in it. After
listening for some time, I became curious as to why some hams
were giving out poor IMD reports and verbal reports of "You are
splattering all over" when I wasn't always seeing the same
thing. Some folks were just downright rude with their
reports. I realize that different software packages may give
different IMD measurements, but a few were grossly different.
There seems to be a lot of information about getting things set
right on the transmit side, but not so much on the receive side.
-----------------------------------------------------------------------
Bill Frantz |Security, like correctness, is| Periwinkle
(408)356-8506 |not an add-on feature. - Attr-| 16345
Englewood Ave
www.pwpconsult.com |ibuted to Andrew Tanenbaum | Los Gatos,
CA 95032
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