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Re: LF: CFH plots

To: "Mike Dennison" <[email protected]>
Subject: Re: LF: CFH plots
From: Väinö Lehtoranta <[email protected]>
Date: Sun, 05 Mar 2000 18:17:32 +0200
Cc: [email protected]
In-reply-to: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
Hi Mike,

Thanks for interesting pictures of CFH signal variation.
You can certainly receive it much better than I can here.
It is most probably due to my qth on higher latitudes.

On 2nd March I weakly heard CFH after 2230z
with around -131 dBmW input on ESH2 (abt -4 dB(uV/m).

On 4th March I didn't hear it at all (below -135 dBmW).

Approximate estim. field strength with my present system:

Fs (dB(uV/m) = listed dBmW + (107 dB) + (20 dB) , so

during quiet condx can "see" down to -8 dB(uV/m) F-s.

That quiet condx I sometimes have during winter...

This is in agreement with my experiences during past
20 years on the nearby, now closed Measuring station.
With an active calibrated HFH2-Z2 loop the threshold was around -5 dB(uV/m), with a 200 Hz IF B-w that is.
You have any estimate how your dB's compare with F-s?

Please, more pictures like that...  73 de Vaino, OH2LX

At 10:45 5.3.2000 +0000, you wrote:
I have posted two graphs of CFH on my website at: (at the time f writing this
it is not linked from any other page).
One was from last Thursday after the X flare, and may show the immediate
effect of an M flare on propagation.
The other was last night.
They are quite different, and it is interesting to note the differences
and similarities. For instance, on Thursday it rose to a peak of about
S9+10dB at 0230 (just after the M flare) and the fell gradually to dawn,
but last night it peaked S9 at 2300 and very slowly fell from there.
Similarities are dips at about 0400 and a dip and peak at about 0630 (UK
I will post more graphs to improve our understanding of what's normal so
that enhanced propagation and its causes can be identified.

Thanks are due to ON5OO for writing the monitoring software. Does anyone
have a good copy of the original EXE file? The one I posted on my site
is corrupt and I deleted all other copies - doh!
Mike, G3XDV
V.K.Lehtoranta, OH2LX, POBox 50, FIN-05401 Jokela, Finland
------ Tel: +358-9-4173965 ---- Fax: +358-9-4173961 ------
E-mail: vais[email protected] - alias: [email protected] & [email protected]

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