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Hello Stefan,LF
I will be on air from 09.00 till 15.00
Utc.
henny pa3cpm
best 73's
----- Original Message -----
Sent: Sunday, April 01, 2012 8:09
PM
Subject: Re: LF: 8.970Khz
Hi Henny, Uwe, VLF,
Yesterday i did some tests with an
active E field antenna in the forest. I used my normal VLF receive antenna
design. First i didn't expect much since it is said that there are little
chances to receive anything with an E field antenna in the forest at VLF but i
got excellent results! DHO38 easily reached 50 dN S/N. The antenna was hung up
2m above the ground to a branch of a > 20m tree. A small 12V battery was
used for the supply and i took a recording of about 10 minutes. In a previous
test i had QRM coming from the netbook's screen but yesterday i added a single
copper earth rod, 20 cm stuck into the soil. Now the QRM was completely gone
and the levels rised 1 or 2 dB.
Now i want to try if i can receive your
transmission Henny and Uwe, if you have the chance to transmit tomorrow
between 8 UTC until the late afternoon? The longer the better. It is exciting
how clean the band looks there and i really want to have a permanent remote
link to my grabber PC. These are the pre tests...
Will you be on air
tomorrow? :-)
As an additional test i want to add a switch into my
antenna which allows to disable the high pass RC part. I will then see the
difference and who knows, maybe i can receive the ZEVS on 82 Hz. At least i
want to do a recording of > 1 hour. That is such a fascinating WX
here! I love it.
Also i want to do a new VLF transmission test with
the small LOPT transformer from an old TV. It became wet during the last test
and then i had a flash over. Maybe it is damaged but maybe not. If not, i will
transmit at 8972 Hz or so and try to decode a WOLF10 signal on VLF.
I
also ordered some audio transformers in different winding ratios. A galvanic
decoupling, optimal matching to the soundcard, first using a 4:1 and then a
1:10 xfmr with a local ground between the transformers may help to get a lower
noise floor on my 2 orthogonal VLF loops which generate the signals for the
CDF VLF grabber at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
73,
Stefan/DK7FC
Am 01.04.2012 10:34, schrieb henny van elst:
Gm LF,
the tx is on,8.970 Khz 450 mA antenna
current
henny pa3cpm
73's
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