Hello Daniele,
This done by a special TX LED (SFH750V)that is switched into the line
(Drain to +) of the second FET of the active antenna.
73, Stefan
Am 13.05.2010 22:42, schrieb Daniele Tincani:
Hello Stefan,
how do you connect the fiber to the antenna? I mean, how do you
convert from electric to optical?
Cheers
D.
----- Original Message ----- From: "Stefan Schäfer"
<[email protected]>
To: <[email protected]>
Sent: Thursday, May 13, 2010 8:48 PM
Subject: VLF: Outdoor test for different places for active E-field
antennas for VLF
Dear group,
Today i checked 3 different places for my VLF grabber antenna. The
currently used antenna was not touched. I used a second antenna that
uses a fiber optic cable + battery that totally decouples the antenna
from the PC (noise!).
The first time i cheked the QTH in the 7th floor of the institute. The
signal was 20 dB stronger and all local QRM lines are gone!
I created a report with many photos and spectrograms to see the
difference. First it was thought to be just a notice for me but due to
the impressing difference of the received signals i want to share it to
other OMs who are working with active E field antennas. Sorry, it is in
german language but perhaps you can use a online translator, if you are
not german and interested ;-) There are some OMs planning to built an
active antenna for VLF and some who have problems or are sceptic about
these fiber optic cables. Also some are afraid with antennas connected
to the PC, when thunder storms occurr. There, the fiber optic cable is
surely a good way to do it, we know.
So if you want to take a look, look here:
http://www.iup.uni-heidelberg.de/schaefer_vlf/Vergleichstest_Antennenstandorte_UNI_HD.pdf
Wish you a nice weekend and better WX than here ;-)
Stefan/DK7FC
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