Message-ID: <8840D182F8BB7540B173D2B1FA0CA9AB034FEE8F@argos.clb.tcfr.thales>
From: Jean-Louis.RAULT@fr.thalesgroup.com
To: rsgb_lf_group@blacksheep.org
Date: Wed, 5 Jan 2005 13:09:36 +0100
MIME-Version: 1.0
Subject: LF: RE: Re: RE: Re: DI2AG 440KHz...rapid fading
Content-Type: text/plain; charset=iso-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org

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 : owner-rsgb_lf_group@blacksheep.org
> [mailto:owner-rsgb_lf_group@blacksheep.org]De la part de Alan Melia
> Envoyé : mardi 4 janvier 2005 18:17
> À : rsgb_lf_group@blacksheep.org
> 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: <Jean-Louis.RAULT@fr.thalesgroup.com>
> To: <rsgb_lf_group@blacksheep.org>
> 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
> 
> 
>