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Message-ID: <3.0.6.32.20000305181732.00889100@pop.saunalahti.fi>
Date: Sun, 05 Mar 2000 18:17:32 +0200
To: "Mike Dennison" <mike@dennison.demon.co.uk>
From: =?iso-8859-1?Q?V=E4in=F6_Lehtoranta?= <vaiski@dlc.fi>
Subject: Re: LF: CFH plots
Cc: rsgb_lf_group@blacksheep.org
In-reply-to: <dKL3fCAuqjw4EwrW@dennison.demon.co.uk>
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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:
>http://www.dennison.demon.co.uk/mike/cfh.htm (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
>dawn).
>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
>IO91VT
>http://www.dennison.demon.co.uk/activity.htm

----------------------------------------------------------
V.K.Lehtoranta, OH2LX, POBox 50, FIN-05401 Jokela, Finland
------ Tel: +358-9-4173965 ---- Fax: +358-9-4173961 ------
E-mail: vaiski@dlc.fi - alias: oh2lx@dlc.fi & oh2lx@sral.fi