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Re: LF: Beacon to the west

To: <[email protected]>
Subject: Re: LF: Beacon to the west
From: "Alan Melia" <[email protected]>
Date: Wed, 20 Feb 2013 23:10:30 -0000
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Hi Stefan it is difficult to draw any firm conclusions from sporadic
"catches" but shall we say that there is nothing that seems to disprove it.
:-))
I am processing data on the path from CFH Halifax in 2003, before I "saw the
light". This shows a distinct "edge".......so that when the Dst is low (say
<-60nT ) there are no periods of good strength reception. The higher the Dst
the more likely there will be a good night and the lonnger the good period
will be. However picking a night with a higher level of Dst does not ensure
good reception but does make it more probable. I am now looking at details
of selected nights to see if I can determine a relationship to the better
conditions.
I feel a bit like a weather forecaster predicting "sunny periods with
showers, some gusty winds, a little snow in places, accompanied by the odd
thunderstorm" :-)) i.e. "I don't know, but there will be "weather"......."
Alan
G3NYK

----- Original Message ----- From: "Stefan Schäfer" <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 20, 2013 10:01 PM
Subject: Re: LF: Beacon to the west


Jay, Alan, Mark, LF,

Thanks for the discussion and for watching. KU7Z, that sounds like a challenge! Not sure if i can make that path in this time of the year. But we never know...
Alan, did you get more informations which confirm or deny your theory
since the Venezuela grabber is available?
73, Stefan


Am 20.02.2013 16:44, schrieb Alan Melia:
Thanks for that Jay I will factor that into my musings   :-))
I think that is within the range I have been considering.....so that is very useful data. You put the finger on the difficulty of knowing how much the local noise level has shifted, but this is where your long experience is an advantage.
I have a vast amount of data the problem is thinking of a way of
displaying it that will stimulate some new ideas.....plenty to fill my
waking hours :-))
Alan
G3NYK
----- Original Message ----- From: <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 20, 2013 3:01 PM
Subject: Re: LF: Beacon to the west


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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