Re: VLF: Long time transmission on earth antenna

[Markus Vester <markusvester@aol.com>]

Hi Stefan,

 

since 16:54, you are painting a strong 8970 Hz trace on your own VLF grabber, about -69dB (35dB SNR) in the 4.5 mHz window. Interestingly, there is also a 15th harmonic at 134.55 kHz, which appears on your wideband LF grabber at - 80dB (20 dB SNR).

 

Nothing seen on the 0.95 mHz VLF grabber in Nuernberg yet, which may of course be due to me being near the null of your N-S oriented earth antenna.

 

Good luck,

Markus

-----Ursprüngliche Mitteilung-----
Von: Stefan Schäfer <schaefer@iup.uni-heidelberg.de>
An: rsgb_lf_group@blacksheep.org
Cc: Paul <paul@abelian.netcom.co.uk>
Verschickt: Di., 16. Nov. 2010, 14:50
Thema: Re: VLF: Long time transmission on earth antenna

Dear VLF,

I will do some pre-tests today on the earth antenna (testing if GPS can be received in the forest and if the output transformer becomes warm in steady state when running 100 W RF key-down).

Before i will do a (new) short test on 1970 Hz. A loop antenna was built to receive on 1970 Hz. It has still no preamp but is directly fed into the soundcard, anyway... The antenna is now nulling out the strong QRM of the tram line near the institute and i hope for a better S/N.

After that about one hour or so on 8970.00500 Hz.

Starting time is in about 90 minutes.

If someone wants spontaneous to take part, you are invited. The 24 h transmission will then come hopefully in a few days, maybe wednesday/thursday...


73, Stefan/DK7FC

PS: Again note that this is a very weak signal test and cannot be compared with a kite antenna transmission. So do not wonder if the signal doesn't appear at 25 dB S/N in 4.5 mHz ;-)