Alan
Thanks for your comments.
Based on Spectrum Lab's s/n measurement, along with that of WSPR, I would say that we are in a
period where signals are down roughly 6 - 10 dB on the EU > NA T/A path as compared to a month ago.
There have been a few nights where the noise floor was elevated due to thunderstorms in the US but I
am not including them in my observation.
Jay W1VD WD2XNS WE2XGR/2
p.s. I rarely use Argo any more since it is virtually impossible to determine s/n of the received
signals.
----- Original Message -----
From: "Alan Melia" <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 20, 2013 9:32 AM
Subject: Re: LF: Beacon to the west
Hi Jay I am still pondering this, plotting Dst against "period receive signal exceeds xdB" gives a
interesting but not very illumination picture. It provides a cut off when theDstis depressed, but
it shows a wide range of received signals when the Dst is high (towards zero nT). I am still
looking for another factor.
By "quiet period" I mean Kp <2 for 10 days or more.... really quiet geomagnetically and signal
levels seem to be unexpectedly poor. Then signals seem to improve after a low level event say Kp=4
. That led to my idea of ionospheric "leak".
However taking a quick look at the recent conditions, things look active enough to be "normal". It
is very confusing but I am looking to see if it could be explained by just an unfavourable path
length/fading. Unfortunately one needs several stations in different location to either tranmit,
or several receiving stations to receive the same signal to see the effect of this. If some paths
are unfavouable other should be favoured.
One problem also is I do not know what a "subjectively" worse signal means, does it mean 10dB ??
Most likely not waterfal displays are very non-linear so it might only be a dB or two. That could
easily be expained by a fading pattern involving say three different hop modes.
There was a grab recently that shoed Stefan and Markus. Markus was fading to a "ragged" trace at
times whereas Stefan was solid all the time, though they were probably seeing similar fading
conditions.
I am still not convinced that there is not some other effect but I cant find anything:-)) Bit
like "Dark Propagation" :-))
Best Wishes
Alan
G3NYK
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Cc: <[email protected]>; <[email protected]>
Sent: Wednesday, February 20, 2013 12:38 PM
Subject: Re: LF: Beacon to the west
Stefan
Good copy last night ... although some dB short of the 'best' conditions. Seem to recall Alan
mentioning that prolonged 'quiet' periods can be less favorable than those that feature some 'ups
and downs'. Maybe Alan will chime in.
Representative capture below. Copy past 0800Z at http://www.w1vd.com/interestinggrab.html ... if
you squint hard enough.
Jay W1VD WD2XNS WE2XGR/2
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