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AW: LF: Re: 9kHz noise level

To: <[email protected]>
Subject: AW: LF: Re: 9kHz noise level
From: Stefan Schäfer <[email protected]>
Date: Thu, 4 Mar 2010 00:23:48 +0100
References: <[email protected]> <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
Thread-index: Acq7ErvlSfDUCPTCQOq6b06bz4JdwAAEvFGI
Thread-topic: LF: Re: 9kHz noise level
Hello Paul, LF, 
 
I plan to transmit on 8,9700 kHz. Maybe, if i am in phone contact during the 
test i make QSY of some Hz if the RXing station has a carrier/line on this QRG. 
Or would this be a problem?
BTW: My loc will be JN49IS...
Before some days i added the feature to the PA to be keyed by the PC. Probably 
QRSS-60 is an idea?
 
Another question: Paul, do you know other members in the VLF group who live 
near frankfurt? It seems still to be a problem having enough receiving stns in 
the near. But i know that there are several OMs who watch the VLF sector and 
haven't ever transmitted a signal below 1,8MHz. That could be very helpful, 
especially if they are /p with their equipment...
 
73, Stefan

________________________________

Von: [email protected] im Auftrag von Paul Nicholson
Gesendet: Mi 03.03.2010 21:42
An: [email protected]
Betreff: Re: LF: Re: 9kHz noise level



Can the tx frequency be confirmed? I've seen both 8.79 and
8.97 kHz mentioned in LF list messages and web pages.

It looks like Horst Stöcker is using 8.79kHz and Stefan
Schäfer is on 8.97kHz.    Anyone else?

The crucial factor is the level of natural VLF background noise
after sferics have been removed.  A couple of dB either way
will make all the difference to detection.  The noise is quite
variable and can be significantly higher during geomagnetic or
auroral activity, sometimes exhibiting strong bands of hiss.
Generally it is stronger in summer than winter.  At night the
background increases.  This is mostly due to a large number
(10 or 20 per second) of weak sferics, too weak to reliably
remove with simple amplitude threshold blanking.

Check out the night time activity now on

  http://abelian.org/vlf/test.html

This is typical night time activity level when the band is
'flat'.

On the 13th I will try to recalibrate the rx at 9kHz so
that the absolute background level can be displayed reliably.

Range to Frankfurt here is about 840km.  A long shot indeed!
Slightly closer at 522km is a high quality receiver set up by
Claudio Re I1RFQ and Renato Romero IK1QFK.  It is located half
way up a mountain in NW Italy,

    http://www.webalice.it/rromero/pnts_observatory.htm

A live stream is here

    http://194.116.73.37:8000/pontese124.m3u

This very clean stereo stream has E-field on the left and
H-field on the right.
--
Paul Nicholson



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