Why not use a VSA scope?
de N2MLP Brian
Monroe County PA
From: 070@... [mailto:070@...]
Sent: Friday, September 05, 2014 11:19 AM
Subject: Re:  kd8ggn needs help with his trace on 20M this morning
There is only one way to accurately determine your PSK signal quality. That
is with an IMD meter.
Any IMD readings that you might get on the receiving end are inaccurate due
to the influence of other signals on the waterfall, S/N ratio, receiving
The IMD meter as designed by KK7UQ is a standalone wide-band HF receiver
that samples the PSK signal being broadcast by your antenna and
independently calculates the actual IMD reading. There is no physical
connection between the IMD meter and the radio or computer.
There are several web sites that discuss the IMD meter by KK7UQ (Google "IMD
Meter"), but the only source for these meters currently is Jim Neutens KJ3N.
If you are interested, send Jim an email at Jim Nuytens
<jim.kj3n@...> and ask for current pricing and availability. The
meter comes fully assembled and calibrated.
I got mine about a month ago for $139.95 plus Priority Mail shipping charges
and would never want to work PSK without it again. Initially, I thought of
it as a test instrument, but I now consider it to be an operating tool for
use any time I work PSK.
It measures signals for PSK31 and PSK63, but not for PSK125. While that is
not inexpensive, it is well worth the money if PSK is your primary mode of
communication. I know it that it is the case for many 070 club members.
When you transmit, the meter will immediately begin to measure your signal.
It will send both a visual and audio alarm if the IMD is below the standard.
For example, if you change frequency and forget to retune the antenna, the
SWR will be higher than normal and your signal quality will drop. The alarm
sounds and reminds me to retune the antenna.
Also, if you need to run a little higher power than normal to reach a
distant station, or to bust a pileup, you can watch the IMD meter as you
increase power to determine how far you can go before your signal quality
deteriorates. Sending a high-power signal with poor signal quality is not
going to help you reach the other station.
Of course, the IMD meter is an invaluable tool for setup of gain, power,
etc. One thing you will find is that the optimal setup for 20 meters 14.070
MHz might not be the optimal setup for other bands or frequencies, but
without the IMD meter, you would never be aware of the difference.
I learned about the IMD meter from another ham whose credentials include
serving with NASA Mission Control for a number of the Gemini and Apollo
flights. Thus, I valued his opinion enough to make the investment in the
meter. I do not regret that decision.
------ Original Message ------
Received: 09:39 AM CDT, 09/05/2014
From: "shopr3@...  <mailto:shopr3@...%20> "
Subject:  kd8ggn needs help with his trace on 20M this morning
Just had a nice Rag Chew with KD8GGN in ohio this morning he was/is looking
for critique on his signal quality. Sugested he might call cq 070 members
for some Elmers and some added info on the club. A chance for helping keep
ripple off the bands. Robert KD0FIP 1396 LONP 249
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