LWPC claims 7.2 dB anisotropy on the VO1NA to Todmorden
overnight path. That means east-to-west is only 7.2dB more
loss than west-to-east.
For VO1NA to DK7FC the anisotropy is only 5.6 dB. Also VO1NA
at Heidelberg is only 2.8 dB weaker than VO1NA at Todmorden.
These figures suggest that with a good rx at Torbay, a first
T/A east-to-west and a 2-way T/A QSO is within reach.
Perhaps something for the long Winter nights.
VO1NA seems to be stable on 8270.0070093 since that first night.
Perhaps we saw some DOCXO warm-up drift.
Overnight 9th/10th the best signal was between 00:00 and 06:00,
about 13dB S/N
http://abelian.org/vlf/tmp/170511a.gif
Overnight 10th/11th the signal was hardly visible against the
noise, it was a noisy night. The noise was enough to bury a
0.06 fT signal.
It appears the overnight signal is clearly detected on about
half the nights.
As I walked past the E-field antenna yesterday, I paused for
a moment to contemplate the 1.4 electrons currently being
jostled by the field from Joe's transmitter at the other side
of the Atlantic. I could see Pendle Hill 24km away and tried
to imagine the transmitter 150 times further away.
Jim wrote:
> have we seen natural-propagation-related frequency changes
> on this timescale?
The most rapid changes are during the terminators, LWPC predicts
a deviation of 25 uHz for about 4 hours as the terminators cross
the Atlantic. Outside those periods it should be stable within
a few uHz, say within 5uHz. The T/A signal from W4DEX was stable
away from the terminators.
Joe wrote:
> The sigs will continue until the helix sparks or the wx grounds
> the aerial.
Well I think I've got all I can get out of this signal for now.
It's not strong enough to measure how the phase is varying
during the night or day. This weekend I'll have time to take
a closer look at the recording.
--
Paul Nicholson
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