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Laura,
don't know for sure whether it's the same
site, I was hoping someone in the group might have more information. This
afternoon, Paul Nicholson's http://abelian.org/vlf/spectrum.shtml showed similar
azimuth, -48 degrees for 18.3 kHz and -44 for 21.75 kHz.
Thanks for the pointer to Peter Schnoor's plots.
Both show the sunrise dip at the same time (6:15), but the midday
maximum is only present on 18.3 kHz. But this may well be due to
different groundwave vs skywave fringe patterns for the two
frequencies. A few years ago, DHO-38 was also temporarily
operating on two similarly spaced frequencies, showing very
different propagation patterns: df6nm.bplaced.net/VLF/2006/vlf_DHO_dualfreq.htm .
Best 73,
Markus
Sent: Thursday, March 13, 2014 8:14 PM
Subject: Aw: VLF: HWU dual frequency?
Marcus,
You wrote:
>
...
> I wonder if they are using the same antenna for both carriers,
> ...
Are you sure? Diurnal patterns from Kiel VLF Grappa look
quite different:
http://lf-radio.de/cgi-bin/ki/plot_channel.cgi?date=14-03-12&freq=21.7KHz
http://lf-radio.de/cgi-bin/ki/plot_channel.cgi?date=14-03-12&freq=18.3KHz
Laura
Sent
from my DoubtPhone
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