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Date: Sat, 04 Jun 2011 22:14:45 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: Advanced notice of VLF transmission tests
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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/
> http://www.g3xbm.co.uk
> http://www.youtube.com/user/g3xbm
> https://sites.google.com/site/sub9khz/
>