Hi Stefan, Gerhard, ELF
The pre-amp is your circuit, Stefan, with the input FET on the antenna
and connected through 10m of twisted pair. For normal VLF work I also
added a op amp to the output of the second FE. This rolls off
below1.3kHz and drives 30m of coax to my computer upstairs in the house
through two cheap 600 ohm line isolating transformers. The ZEVS signals
are doing well to get through the LF filtering. I haven't changed the
LPF in SL which is still set at 22kHz - the default settings for normal
VLF. The hum filter is switched on and significantly reduces the 50Hz
component.
73 Chris G3WCD
On 08/05/2011 22:27, Stefan Schäfer wrote:
Hello Chris, Gerhard, ELF,
I've also seen a stable trace at 82 Hz but not the frequency shifting
transmission before. For some reasons there are various QRM levels
here and i don't know the origin. Never mind and interesting to see
something at all. Would be interesting to see what can be achieved
with an ELF optimised crcuit...
My SL settings include a 700 Hz LPF and the noiseblanker afterwards,
using the usual VLF settings. The width of one FFT bin is at 11 mHz
and the scroll rate is 1 pix/minute which seems to be a bit to slow. I
will change to 30 sec/pix soon. I've switched on the "Paul Nicholsons
hum filter" and set the hum frequency to 16 2/3 Hz to remove 50 Hz and
16 2/3 Hz harmonics of the German train power grid.
Maybe a simple mains transformer allows a simple way to realise a LPF?
73, Stefan/DK7FC
Am 08.05.2011 22:57, schrieb Gerhard Hickl:
Hi Chris, LF!
Very interesting....I'm also using Stefan's E-probe and on 9khz ist's
very sensitive. My probe is more than 15m above ground and I'm also
trying to receive the ZEVS-transmissions. I have the window running
since a few days but nothing on screen here in JN88hl....
I'm just using a low-pass filter with 1000Hz -3db point and the
noise-blanker afterwards. I wonder about your SL-settings.
73
OE3GHB
Gerhard
Am Sonntag, den 08.05.2011, 18:58 +0100 schrieb Chris Dillon:
Hi all - ZEVS transmission starting at 1800 BST received at IO92vf
using a 'Stefan' pre-amp with a 1m probe about 3m high.
Still transmitting a constant carrier on 82 Hz at 1857 BST. Wonder if
they QSL reception reports?!
73 Chris G3WCD
On 08/05/2011 09:37, qrss wrote:
Stefan / LF
Message commenced 0800UTC.
Eddie
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