VLF,
Am 26.11.2011 17:55, schrieb Markus Vester:
Once more, Paul Nicholson is showing
a good trace:
Wow, yes, very good!
Well, the system runs on the GPS locked system now since 17:00 UTC and
i'm running 780 mA on 8970.00000 Hz. Will go for dinner now and leave
the system running some hours. The WX looks quite useful, no rain, poor
wind and no fog! Maybe i will even run it overnight until tomorrow,
transmitting a streight carrier at 350 W RF. Can't do more
unfortunately, due to the cola-cap ;-)
Now as the signal is locked and non-drifting there may come up
something on the 6000-windows...
Maybe Paul or others can do some calculations, estimating the ERP? I
think it should be in the range of 200 uW. Up to 6 dB can be added in
further tests, i hope.
Markus, a S/N (better S and N ;-) ) plot on your side would be
interesting. My ERP should be constant now so we can observe the QSB,
caused by propagation...
A photo of the todays arrangement:
http://dl.dropbox.com/u/19882028/VLF/DSC04268.JPG
73, GL, Stefan/DK7FC
... well done!
Markus
Sent: Saturday, November 26, 2011 4:33 PM
Subject: Re: VLF: 8970 Hz transmissions, soon again here
Stefan,
around 15:00, your sig on 8970.008
was visible in Nuernberg, peaking ~ 20 dB SNR in 0.48 mHz.
Viel Glück,
Markus (DF6NM)
Sent: Saturday, November 26, 2011 3:57 PM
Subject: Re: VLF: 8970 Hz transmissions, soon again here
VLF,
I'm now running 350W into the system and get about 0.8 A antenna
current. Strong audible partial discharges occurr on a parallel fixed
plate capacitor, spaced by 3 cola bottles (0.33l ;-) ). At 550 mH i
have
25 kV rms on the antenna and coil which seems to be no problem at all.
The frequency is still a bit unstable since i took the DDS VFO which is
more comfortable to find the resonance. I will now try to slightly QRO
and then apply a fiber optic cable carrying the GPS locked frequency
coming from the PC/SpecLab, hopefully without to many phase glitches.
Currently i may have an offset of some 20...30 mHz and a slight drift
but it is a first successfully test :-)
73, Stefan/DK7FC
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