Hello Roger,
Am 04.06.2011 18:49, schrieb Roger Lapthorn:
Stefan, DK7FC, when are you intending to do some tests from your fixed
VLF station please? 17dB weaker may be copyable here in 424uHz if
continuous carrier. I am really looking forward to this.
Well, some infos about what i plan in then next time and when.
I'll take the TX coil to the antenna in Heidelberg probably next week.
Then i will arrange the station and do some first tests to find the
resonance frequency. This may be probably a bit above 9 kHz, maybe 10
kHz. Then i have to add some copper rods on HV near a grounded plate on
the wall to get some more C. If the signals and ground losses are
reasonable good, i shall replace the additional C by some addional L
(probably such a bucket as Markus has) to get a better ERP.
I assume the ERP will be about 1 mW. I assume lower earth losses. My TX
power is not limited any more! The limit will be the HV withstand
voltage of the coil, i estimate about 50 kV rms which is no problem for
the antenna, neither for the wire (which is 10mm diameter) nor the
insulators (36 kV rms 24/7 under rain or snow). Depending on the earth
losses, this limits the maximum power to be applied. But the PA can
produce 1...2 kW without problems i think. So i will run as much power
as possible.
If all works well and i can find a place in the institute where i can
place the coil for a longer time, i'll be QRV regularly, transmitting
DFCW-600 to 60000. I will announce that here before, as usual.
So, no need to worry to miss anything. I will inform you after the first
tests.
I expect to be visible in a radius of 800 km in DFCW-600 on a quiet day
in a quiet location, hopefully ;-)
73, Stefan/DK7FC
Thanks Chris G3XIZ for today's test and for the advanced notice. Have
a good holiday.
73s
Roger G3XBM
--
http://g3xbm-qrp.blogspot.com/
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