Hello Roger,
Tnx for your tests and report. Well, yes, i haven't looked for you but
G3ZJO did, as visible on his grabber. I saw no tryce of you there.
Congrats to your new DX. It may be useful to use the same settings to
compare to the last best DX. If i remember correctly, your last best DX
was arround 5 km but in QRSS-3? Of course the signal will go farer when
using 11 mHz instead of 0.18 Hz.
Do you use the blanker settings as well? This improves the signal by
arround 6 dB or more, depending on the noise of course.
How do you generate the TX frequency? You may use SL itselfe at home
and generate 0...24 kHz directly coming out of the soundcard, feeding
your PA. Then you can generate QRSS and even stepping frequencies. So
you can directly check which frequency is the best at a given QTH, TX
power, RX antenna and polarisation, WX, etc... Maybe this allows
further extended interesting tests :-) Just an idea.
73 es go on!
Stefan/DK7FC
Am 17.07.2011 19:54, schrieb Roger Lapthorn:
After lunch I did further tests at 8.7605kHz using long
carriers interspersed with brief off periods for ID. Having had some
success away from roadsides this morning I was hopeful of more "local"
DX this afternoon. When I tried reception at a distance of 7km using
one earth rod in Bottisham Lode (a fenland waterway) and one about 15m
in from the water's edge in the soil no copy was achieved, even with SL
in bandwidths of around 4.5mHz. Looking at the map it is not clear this
waterway is directly connected to the watercourse I was using
successfully this morning.
Not to be beaten, I tried another reception test at a second location
exactly 6km from the home QTH - this is 0.4km further than ever before.
I tried to find the watercourse beside the road, but it was totally
overgrown and inaccessible. So, instead I placed the 2 earth electrodes
alongside the road (i.e. parallel to the road) in a line that would
have been also parallel to the water in the water drainage ditch, if
there.
Using SL, with 11mHz settings as for the test before lunch, good copy
was immediately achieved of the 5W test transmitter back at home. As
before, I got my XYL to cut carrier for a 5 minute period (actually
more like 8 mins as she forgot to turn it on again!) and the signal
reappeared with the same thermal drift seen earlier. Also, I noticed
that the signal was just visible with Spectran in 0.18Hz bandwidth.
Results with a single turn loop on the ground and the 18m spaced
earth-electrode pair were similar in S/N. I'm still not sure what
orientation is optimum for either schemes.
My new earth-mode DX is exactly 6km and my best yet. S/N
in 11mHz was around 10dB, so there is more to be had yet, especially
with more TX power (currently just 5W), better stability, moving down
below 1kHz and even narrower SL bandwidths (currently 11mHz).
With our 40th wedding anniversary and family commitments there will be
a break in tests for a couple of weeks now, but I have lots of new
things to try still.
I assume no-one else was looking for my signal (or certainly no-one was
successful) locally today?
73s
Roger G3XBM
--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
https://sites.google.com/site/sub9khz/
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