Hi Roger,
Nice to hear about your progress.
Do you have snow as well in JO02 ? Maybe this makes it more comfortable
to have the RX at home and the TX in 5 km distance in the forest where
you can easily arrange a 100m earth antenna, even in some height above
ground :-)
Good luck and fun there!
73, Stefan
Am 10.12.2010 14:53, schrieb Roger Lapthorn:
Today I did a test receiving my 8.76kHz QRSS3 VLF signal
5.1km away from the home comparing reception using (a) an 80cm loop
antenna and (b) a small earth electrode antenna (14m spacing) using a
variety of pre-amps. Although quite solid reception (17dB S/N in
0.18Hz BW) was achieved using the loop laying flat on the ground, there
was absolutely nothing detected using the earth electrodes which were
pushed into the soil either side of the road, which was both surprising
and disappointing. I used the very same pre-amp in both cases and also
tried the lo-Z input 8-9kHz tuned pre-amp with the earth electrodes
that successfully copied DK7FC at 648km last weekend on the earth
electrodes at home.
Several possibilities for the failure with the earth electrodes at the
RX site:
- The electrode spacing was far too small
- The barbecue skewers used as RX electrodes were too short and
not making decent soil contact
- The soil was too wet, so the pick-up (effective loop area in
the ground) was lower than with dry, low conductivity soil; the test
site is in the fens where the soil is a dark peat.
Next step is to repeat the test up on the chalk uplands to the south of
the QTH at about 4km distance where soil conductivity will be lower and
to try a larger earth electrode spacing on receive.
When compared with the 2873km DX by Stefan this is nothing to
get too excited about, but fun experiments nonetheless.
73s
Roger G3XBM
--
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk
www.youtube.com/user/g3xbm
G3XBM GQRP 1678 ISWL G11088
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