Hi Roger
Yes quite so, re such comparisons and very very weak signals, I am
just considering the possibility of telling if a signal is there or
not by eye. BTW before anyone notices in my idea of comparing with
Morse elements, there are no element spaces in WSPR and you get a
few together at time but it maybe out by a factor of 10, it was all
done quickly in a tired head :-)
We ought to save the comparison figures for modes I never can
remember them.
Eddie
On 27/04/2011 21:45, Roger Lapthorn wrote:
Dear Eddie (et al)
In the context of the very very weak signals experienced
at VLF I don't think WSPR is a serious contender except for
localised tests. No doubt someone here far more knowledgeable than
me can tell us the "dB advantage" of say, QRSS600 or 6000 versus
WSPR, but the difference must be enormous.
Where WSPR scores, in my view, is the automatic reporting via the
internet database. This has proved a real boon at 137 and 500kHz.
Even here though very slow QRSS would beat WSPR every time. I am
a great believer in WSPR, but do not believe it will be that much
use at VLF.
Andy (G4JNT) are you able to comment on please?
73s
Roger G3XBM
On 27 April 2011 20:51, qrss <[email protected]>
wrote:
Just a further thought.
WSPR doesn't of course spread its power over 6Hz it actually
transmits full carrier on each of the four frequencies for
0.682 mS and sometimes several of the same element follow
without a break in carrier, which accounts for some of the
bright spots and lines we see when things are marginal. One
element is a longer dot time than 2WPM Morse, and that is
SLOW Morse.
Long integration times are out of course.
73 Eddie G3ZJO
On 27/04/2011 18:58, Roger Lapthorn wrote:
Hi Eddie (et al)
It is highly unlikely you'd copy Andrew on VLF
remembering that the WSPR signal spreads around 6Hz in
the transmission burst, so the energy in any narrow
FFT bin would be tiny. Also, this is earth mode (I
hope, as G6ALB does not hold an NoV to radiate at
VLF), so signals are propagating through the ground by
conduction and no significant amount of signal is
radiated.
I'm still intrigued why the best reception here today
was with my 80sq m vertical loop. This outperformed
several earth electrode set-ups here at the RX end, an
E-field probe and a 30t loop laying close to copper
pipe work in the house! If the signals are coming
down the pipes then why don't these more direct means
of coupling to them work as well as (or better than) a
vertical loop outside? Odd.
73s
Roger G3XBM
On 27 April 2011 18:33, qrss
<[email protected]>
wrote:
Great stuff Roger
and Andrew
If you are RX'ing on an 80m dipole it may be worth
a look here, I would never say can't until I have
tried. Bearing in mind I should be able to observe
signals which would not be decode able on WSPR
I would appreciate a prior notification of times
and exact frequency of the WSPR signal of any
further tests.
Keep it up.
73 Eddie G3ZJO
On 27/04/2011 15:19, Roger Lapthorn wrote:
As
an experiment I changed over to my wife's
laptop and got immediate decodes of G6ALB's
VLF earth mode signal (3km) at -17dB S/N,
suggesting the issue with lack of decodes
may be with my soundcard and not Andrew's.
1408 -17 -0.6 0.008986 0 G6ALB JO02 47
1410 -17 -0.6 0.008986 0 G6ALB JO02 47
1412 -17 -1.2 0.008986 0 G6ALB JO02 47
1414 -17 -0.8 0.008986 0 G6ALB JO02 47
1416 -17 -0.8 0.008986 0 G6ALB JO02 47
This is a very solid signal on the 80m
square single turn vertical wire loop
antenna. Andrew is using 44W to an earth
electrode antenna.
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/
--
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
https://sites.google.com/site/sub9khz/
--
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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