[Lowfer] More Frosty MP-XGJ (Now fortified with SL at no extra charge!)
JD
listread at lwca.org
Sun Jan 15 06:52:27 EST 2012
>>>Thanks for the great capture, you must have a nice quiet location for the
>>>sigs to be audible!
It is reasonably quiet if we don't have a northeast wind, or if it hasn't
recently rained. Those seem to be the main factors in noise on our rural
power lines. Being well outside town and having no neighbors closer than
1/4 mile also helps.
QRN is generally the limiting factor. Static crashes during early evening
were frequently up to S7, with intermittent ones to S9. That's with the
buffer amp at the antenna. Without it, the mismatch is so severe that the
S-meter would have been sitting calmly at 2.5, its resting level. Last year
at this time, when I didn't have the buffer's help, the same signals were
usually visible but seldom audible.
Upon returning to the field later tonight, I achieved another similar
capture of MP and XGJ (not shown here). I noticed that the static seemed a
little less frequent and the audio wasn't as loud. That should have piqued
my curiousity, but it didn't...the volume is always highly dependent on
where I place the computer because it partially blocks the radio's speaker.
With the same signals displaying about as well as they had earlier, I was
content. Later, I tuned down and caught SL (attached) at about 136.1733.
This view is stitched together from over 90 minutes of watching. I was
pretty happy with that one, too, although I wonder what that glitch is near
the end.
Then I went up to 600 meters and listened to WD2XSH/31 in CW on 477.870
about 2:40 AM. Down the dial a bit was /7 in both regular CW and commercial
speed on 476.3, followed by PSK31. Some sort of pseudo-Morse was on 490.
And there appeared to be two stations using WSPR or Olivia or something
similar at 495.901 and 495.904, give or take half a hertz (also included in
the capture).
France Inter, Europe 1, and Iceland were all very strong around 3 AM, which
is surprisingly late for such good signals from them. After listening to
them a while, I made sure DCF77 and JJY (40 kHz) were both nice and clear.
(Haven't heard HBG in a couple of weeks now, though!) Even did a little AM
band DXing, despite the buffer amp containing low pass filtering. Then I
packed up to come home.
That's when it hit me. I'd spent the entire second session tonight
listening with the shorting strap in place!
This is the first time in several weeks that I've done that. I think it's
because I've gone back to using longer clip leads to connect the buffer to
the wire running up the pole. When I connect with shorter leads, as I had
been doing recently, I'm right down near ground level. However, with the
longer leads I connect higher up on the pole, and apparently I don't think
to look down at the strap or don't see it as well in the dark. Evidently
it's not much of a short at RF...or else I'm connecting high enough to get
effective shunt coupling for most purposes.
Still, I probably missed some things I could have seen otherwise. The
attached capture shows hints of signal at 136.1725, and there were wisps at
.171 and .172 on the originals as well. Also, the fruitless hour I spent
watching for JAM might have turned out differently without the strap, as
there were a few faint indications of signal there, too.
I'll try again this coming night. It is supposed to be several degrees
warmer, although the next weather system will also be approaching, and I
have no idea whether it will be as electrically quiet. But it will be my
last good chance for a week, as the deadline for my LOWDOWN stuff is
looming.
John D
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