Hi Jean-Louis, sometimes it does, but I think there are a lot of different
frequencies stimulated. I have had a few attempts to fourier analyse the
plots, but not with a great deal of enthusiasm yet. If I look at a lot of my
recordings there are obviously cases of beats between "waves" of different
periods. But theory.....well no not yet....I am an empiricist.....get the
measurements first and find a theory to fit later.
I think there are things called "gravity waves" talked about in the realms
of atmospheric and ionspheric physics (KN4LF's MF Propagation site has a
reference to them), but I have not yet found much else of interest
yet,except on I think it was the NOAA site, a program that prints out a
quasi 3d representation of an oscillating sphere. I can envisage a mechanism
that attenuates the high frequencies first but have not tried to work it
out. I think that ocean waves might be the nearest analogue. The problem is
that unlike water, the medium has a rapidly reducing density. Maybe there
are some keen mathematicians around who would care to play with the ideas.
Also the CME and solar wind is an "electro-magnetic" interaction. If it were
not for the earths field I think the solar ions would penertrate right down
into the atmosphere.
Like all things it is probably a lot more complex, but at least I have a
handle to enable me to talk about it and gather ideas.
Cheers de Alan G3NYK
alan.melia(at)btinternet.com
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: 05 January 2005 12:09
Subject: LF: RE: Re: RE: Re: DI2AG 440KHz...rapid fading
Hello Alan
Thanks for your interesting suggestion.
I'm wondering why the "oscillating mirror" frequency would decrease when
time passes.
The amplitude of a jelly portion wobble decreases when the losses dampen the
oscillations, but not the frequency which remains stable.
So I would expect some diminishing QSB amplitude on the DI2AG records, and
not QSB frequency decrease.
Please what is the underlying theory about this frequency vs time decrease ?
73
Jean-Louis F6AGR
-----Message d'origine-----
De : [email protected]
[mailto:[email protected]]De la part de Alan Melia
Envoyé : mardi 4 janvier 2005 18:17
À : [email protected]
Objet : LF: Re: RE: Re: DI2AG 440KHz...rapid fading
Hi Jean-Louis, and Walter. I see a rapid almost cyclical
fading on some
136kHz signals immediately after a geomagnetic storm (we have
had several
minor storms Kp=5 recently), the period usually lengthens on
successive
nights. I have suggested that this might be due to the plasma cloud
"slapping" the ionosphere on one side and it then "ringing"
like a wobbly
jelly ( I must have eaten too much this Christmas !!) This
would cause the
"reflection" level to move up and down a few hundreds of
metres maybe even a
kilometre, which is quite sufficient to swing through a
180degree phase
change. The movement required for a "null" at 440kHz is much
less than at
136kHz. I would certainly be interested to see if the period
of the fades
increases over the course of the next few nights.
Cheers de Alan G3NYK
alan.melia(at)btinternet.com
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: 04 January 2005 13:48
Subject: LF: RE: Re: DI2AG 440KHz
> Walter et al.
>
> I recorded your DI2AG sigs last night from 6 PM to 6 AM .
> A quick exam on the 150 ARGO snapshots during my tea time early this
morning tend to show a deep QSB (period around 1 minute).
> Have you got other similar remarks ?
>
> 73
>
> Jean-Louis F6AGR
> Loc. JN18DQ, near Paris
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