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Re: LF: Observation, drop in LF noise

To: [email protected]
Subject: Re: LF: Observation, drop in LF noise
From: Väinö Lehtoranta <[email protected]>
Date: Thu, 23 Mar 2000 18:37:16 +0200
In-reply-to: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
Hi Larry, a very short comment follows:

Assume your noise level depends on ionospherically
reflected signals, possibly from natural sources as
the case often is at least on lower latitudes.
My corr geomagnetic latitude is about 57 degrees
and I can notice reduction of "sky-wave" signals
(before?) during or after a solar M/X level event.
I've kept daily log of LF noise level in hope to get
some new ideas. Unfortunately man-made noise of
some kind is getting worse especially on LF freqs.
It is a paradox that for more than 30 years of
time we had a stationary order to keep that kind
of log of LF/MF noise levels but actually we didn't.
Would be interesting to know what stations you hear
on 189.000 and/or 189.008, possibly via ground wave?
73 de Vaino, OH2LX






Greetings All:
The following is an observation the occurred about an hour ago that may be
of interest to some in the LF and LowFer communities.
I am watching 189.000 +30, -30 Hz with Gram continuously while I am in the
shack here.  There are two signals I am seeing on this part of the
spectrum, one carrier that goes on and off from time to time is on 189.008
kHz.  There is a much weaker signal on 189.000 that in the daytime is a
faint trace line.  There is another signal that is louder in the evening on
189.000, I am assuming the two signals on 189.000 are from different
sources.  I am looking for a LowFer beacon signal on 189.000, so far I can
not confirm I have seen it.
There was an M class flare at 11.59 utc, peaked at 12:14 utc, ended at
12:33 utc.
At about 12:48 utc the screen presentation from Gram suddenly went from
typical noise spots to almost ZERO noise, the signal level on 189.008 kHz
stayed the same level and the trace signal on 189.000 kHz stayed the same
level although it was certainly easier to see.  Without having the
confidence of my observation I started poking around for a bad RF connector
in the system.  The duration of the low noise was for very nearly two
minutes then the noise returned to normal levels.  By this point I had
nearly torn the place apart looking for the bad connector that I now feel
does not exist.  The low noise period had moved to very nearly the edge of
the screen when I realized that the 189.008 kHz signal level had stayed the
same throughout the event period, only the noise had changed in level.
The 15 minute difference from the end of the M level solar event started me wondering if the lack of noise and the M level event might be related. If anyone else has an observation of a varying level of noise on LF during
this time period today I would be interested to hear about it.
Larry
VA3LK

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V.K.Lehtoranta, OH2LX, POBox 50, FIN-05401 Jokela, Finland
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