Hallo Markus,
Very nice! It's a short clear dit on that frequency but the identical
time and frequency on the various grabbers makes it even more plausible
that it's yours, so crongratulations! It is your first trace at IK1QFK,
right?
73, Stefan
-------- Original-Nachricht --------
Great
thanks to Max, Eddie and Gary for activating screen uploads.
The carrier was on air from 4:40 to 11:00 UT, with about 0.36 A antenna
current and stable phase. It was nicely visible on Paul's "gold
standard" spectrogram in Todmorden, and partly in 424 uHz in Heidelberg
on Stefan's tree. The attached screenshot shows potential 47 uHz
detections in Cumiana (IK1QFK, Friday, top) and Heidelberg (DK7FC tree,
Friday and Sunday, bottom). Unfortunately today's transmission did not
result in a clearer trace in Cumiana, so I'll have to try that
again under quieter conditions.
Best 73,
Markus (DF6NM)
-----Ursprüngliche Mitteilung-----
Von: Markus Vester <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: So, 3 Jul 2016 12:00 am
Betreff: Summertime VLF: 8270.0025 Friday, Sunday
Yesterday
(July 1st) I attempted to improve the cooling and to reduce the
acoustical emission from my VLF loading coil. A large 12 volt fan was
placed above the top of the coil, powered directly by the rectified
antenna current. The high voltage and electric fields at the motor did
not seem affect the electronic commutation. To reduce heat
buildup inside the enclosure, the inner wall of the lower blue bucket
was lined with a coil made of thin polyethylene tube, which was
manually fed with cooling water by swapping the upper and lower
canisters from time to time. Finally the remaining narrow slot
between the two outer buckets was tightly sealed with tape, which
indeed attenuated the annoying coil beep very significantly.
Then I ran a carrier on 8270.0025 from 11 to 15:30 UT. Unfortunately at
that time, the QRN was already quite strong, preventing a detection in
the 424 uHz grabber windows of DK7FC and OK2BVG. But after the long
transmission, a couple of promising brighter pixels did show up at the
right place in the 47 uHz instances in Heidelberg and probably also in
Cumiana at IK1QFK.
Today's weather was not favourable but we expect better conditions
tomorrow morning. So if all goes well, I will try to repeat the carrier
transmission on Sunday morning 6 to 11 UT (July 3rd,
overlapping with SAQ), hopefully in lower background noise. Tomorrow's
goal would be clearer detection in Cumiana, but of course I'd also very
much appreciate possible detections from anyone anywhere else. I
will also try to send more EbNaut later but not tomorrow.
BTW I have also reactivated my slow VLF grabber windows on the
permanent "summer antenna" (a passive E-field probe in the garden),
which is permanently serving the 137 kHz and Loran-C receivers. On
LF it is somewhat plagued by ADSL and powerline pickup, but the QRM
situation may be different at 8.27 kHz. I actually need some
amateur signals to find out how good it is ;-).
All the best,
Markus (DF6NM)
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