Hello Jim, ULF,
Am 13.12.2016 01:13, schrieb [email protected]:
If you have ruled out phase jumps from corona (which I think you did rule out)
Today i did. I sent an unmodulated carrier from 10:30...18:38 UTC today
(maybe useful for Paul who's probably working in the background :-) )
and monitored the signal in 30m distance. Of course the signal levels
are very strong there and we can exclude any propagation effects. I can
confirm there was no change in the colour (equal to the phase) in the
transmission. It was interesting to see sidebands at +- 0.5 Hz and about
-50 dBc, which probably come from the samplerate drift compensation
which happens each second. So it all works as expected. On the tree, the
colour changes were visible again, but the variations were quite weakly
expressed today.
my next thoughts would include (among other things) variations in diffraction
and/or re-radiation from local geography and infrastructure,
I think this is unlikely because there is no electricity on the receive
site on the tree, nothing like trees and stones in a radius of 1000m.
If your initial SNR measurements at 65 km are representative (first pixels 20dB
at 47 uHz?),
20 dB at 424 uHz, after sferic blanking, in daytime. You're right, i
should try to
BTW the noise was so low that it looks like i am system noise limited,
not natural noise limited. So i built a new and better preamp today,
with two op amp stages, inspirations taken from
http://www.vlf.it/feletti2/idealloop.html
The VLF/ULF band noise is really very very low these days, i'm regularly
impressed. Oh and i'm planning a 130 km experiment in the next few
weeks. Before that i'm doing a local experiment just to test the new
preamp together with the loop.
In this 130km experiment i will rise the power by 3 dB, about 150 mA
antenna current. That should be enough to see the signal in that
distance in 424 uHz. Ah and the plan is to do it in France, JN38OO could
be the region of interest...
73, Stefan
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