Hi Dave thanks for those comments, I dont often listen at HF these days so
would not know what to expect. I use the NOAA site for Kp which hit 5 this
morning on the Boulder estimate. But I use the Dst estimate to judge the
electron precipitation into the D-layer. This mimics the continuing
absorption well after the Kp has returned to "quiet". It is a kind of
measurement of the size of the reservoir of electrons available in the Ring
Current in the Van Allen belts, which enter the ionosphere at the sunrise
edge. LF conditions at night stay depressed until the reservoir is near
exhasted.
My guess is the D-layer is normally absorbing at 500k but I wondered if it
might switch to "refecting" if the injection was high enough.
Cheers de Alan G3NYK
----- Original Message -----
From: Dave Sergeant <[email protected]>
To: <[email protected]>
Sent: 23 May 2007 13:16
Subject: Re: LF: 500 propagation
> On 23 May 2007 at 12:56, Alan Melia wrote:
>
> > Hi all, there was a geomagnetic event this morning and whilst small it
> > is likely to be extended to tomorrow as well. We have not really had
> > such an event yet whilst 500k permits have been active. I would be
> > interested to know from regular users and listeners whether the signal
> > levels are enhanced over your expectations (particularly around the
> > middle of the day) or as I suspect are weaker. 500k is different to
> > 136k where the current conditions could boost daytime signals
> > slightly. I also think night-time signals may be slightly weaker,
> > similar to 136k.
> >
> > Thanks and Cheers de Alan G3NYK
> >
> >
>
> Guess that explains why the HF bands are so dire this morning.... All
> I hear on 500kHz at the moment is noise...
>
> There is no indication of this event on the DK0WCY magnetometer, it
> says 'quiet', 'quiet' though I see the K index has been up at 4.
> (http://www.dk0wcy.de/magneto/magnet.htm)
>
> 73 Dave G3YMC
>
> http://www.davesergeant.com
>
>
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