Hi VLF,
I'm back from LF for a while and built up my large VLF coil which was
used on 2970 Hz in the beginning of the year. Actually it is under
maintenance, one of the six stacks has to be replaced. It is already
dismantled but the new wire is not yet wound on the 250 mm diameter PVC
tube again.
So now the resonance is higher! I didn't know where it is and just
connected the coil and scanned the frequency downwards. Near 3685 Hz i
found a maximum of the antenna. Since the Q is not extremely high, i
decided to tune to 3675 Hz and added the usual 5 mHz offset, to stay
away from multiples of 1 Hz.
So, now since 14:40 UTC a carrier is running on 3675.005 Hz.
The antenna current is 170 mA. I estimate the ERP is just 3
uW!
I guess this is a first amateur radio transmission on the 82 km
band and that class of ERP (?).
Hopefully the coil will hold the 15.5 kV with just 5 stacks of
windings. It's inductance is 3.9 H in the moment!
I intend to run the carrier for at least a few days, depending on the
feedback.
Good luck for the VLF experts!
73, Stefan
PS: A 424 uHz RDF spectrogram is running at
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
(First pixel appears in 30 minutes)
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