Hello Piotr,
Nice to see/read again from you here on the reflector! :-)
Thank you for your very nice words and for the effort on updating the
propagation model for my current setup! It is very interesting for me!!
If the S/N in 904 km is so good and the E field decrease (as a function
of distance) is like you show, i assume a transatlantic
contact/reception is not to far away! All the things that happend in the
last time is still a little unbelivable for me, it takes some time ;-)
The link to the IEEE paper is very interesting as well! Maybe the
scientists over there are interested to take part on the experiments? Do
you know some of them? Maybe we can combine the amateurs and the
scientific work, although they will have no appreciation if i transmit
"73" instead of a constant carrier ;-)
Will you try to receive on the next experiment as well?
Vy 73 and i wish you all the best!
Stefan/DK7FC
PS: If you have the time, could you give us some ideas to compare 8970
Hz and 6470 Hz? Or even 5170 Hz if i can set up a 300m vertical? Maybe i
should do the first test on 5170 Hz before you take the effort ;-)
Stefan/DK7FC
Am 04.10.2010 22:44, schrieb Piotr Mlynarski:
Stefan Schäfer pisze:
Wow!
Dear VLF,
This was very nice to read. So many messages and so many positive
receptions. I am really impressed!
*Many thanks to you all* who have been active on this day, watching
on 8,97 kHz, the Dreamers Band :-)
*We have a new world record of the maximum distanced reception on VLF
(by amateurs): SQ5BPF at a distance of 904 km with excellent S/N.*
Congratulations!! See attached picture.
Thanks to Markus/DF6NM for QSP to the reflector. Sorry to Wolf/DL4YHF
that i was not QRV on 2m CW but there were problems to that time (see
below). Thanks to SQ5BPF for the positive SMS ;-) Thanks to the US
and canadian stations who tried to receive the signal. It becomes
more and more probably since the S/N values are impressive here in EU.
Congratulations to all successful receiving stations, especially the
new ones (on 8970 Hz) which are as far as i can see: Daniele Tincani,
SQ5BPF, DD7PC, DF0WD, F1AFJ (683 km since my locator is/was JN49IS),
F5WK (very impressive S/N 25 dB at 460km distance!), DL3ZID(463 km) :-)
Dear Stefan, VLF ,
Congratulations to you for ,again, your remarkable efforts, passion,
knowledge and skills resulting in another, world-wide acknowledged VLF
experiment.
Unfortunately, i was away from home by the time the experiments were
taking place so i could only read e-mails with rx reports and remarks.
I guess you recall some discussion about field strength ,propagation
models etc.. among some "Dreamers" which took place, here,
on this reflector, after your second/third vlf experiment. Paul
Nicholson has introduced us to a paper dealing with some theoretical
considerations
about EM waves travelling in earth-ionosphere waveguide:
http://dspace.mit.edu/bitstream/handle/1721.1/16973/53712465.pdf;jsessionid=995C2F2A8DC7FFC28D518D8FF1745D7C?sequence=1
I 've written fortran code based on egn. 5.2 of the above paper and i
have already presented some theoretical estimates
based on data taken from your previous experiments. Today, i present
another theoretical E-field strength estimate( attachment) based upon
your recent setup
i.e with assumed antenna current of 1 Amp and its vertical length of
200 meters. The height of ionosphere has been assumed to vary between
60 and 80 km
f = 8970 Hz. A separate, 'single point' calculation has also been
made for the tx-rx distance of 904 km
i.e. between you and Jacek,sq5bpf and the calculated effective field
values for 60,70,80 km of ionosphere height are: 3.32; 2.85; 2.49
respectively
(expressed in microVolts/m).
73, Piotr, sq7mpj
p.s.
in the course of collecting some literature dealing with propagation
models of EM waves in the ELF_VLF_LF range; 'receivers' and 'antennae'
i have found an interesting paper which title ( and contents) reads (
in our,radioamateur vocabulary)
as simply another loop antenna and receiver for VLF reception :-)
http://www-star.stanford.edu/~vlf/publications/2010-02.pdf
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