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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