Hi Jacek,
All very interesting, i cannot stop thinking about ;-)
Your plot_80km.png tells me that in 200 km distance (pretty close to
DF6NM/DJ2LF/DK6NI/DJ6LB), 2500 Hz is the most suitable frequency.
Compared to 8970 Hz, the signal shall be 20 µV stronger, about a factor
5 in field strength (~ 14 dB). This would mean, my signal would be much
stronger even if the losses due to a parallel capacitor would increase
by say 6 dB.
BTW, since i was out of resonance during the 5170 Hz test, the current
was just half the current which would be possible. This means my TX
power on 5170 Hz was just about 150 W! Anyway the S/N at OE3GHB was
about the same as on 6470 Hz where i have had the full power! So the
signal could have been 6 dB stronger!
So, if i would use the 300m kite and switch a parallel capacitor to the
loading coil, 3x the C of the kite wire (about 5 nF/ 30 kV), i could
resonate on 2.5 kHz (crazy!). Although just 1/4 of the coils current
would flow into the wire (< 12 dB losses) my signal would be stronger in
that region! Ah, i have forgotten the lower radiation resistance of the
300m wire on this frequency,ok...
Oh dear, should we really try a 2.5 kHz test?
Another idea: It would be most interesting in a test on the earth
antenna since there is no need to resonate it and the earth losses are
almost independent of frequency! If the frequency decreases, the skip
depth (and so the effective loop area) increases. This might partly
compensate the decrease of efficiency.Wow! I will prepare such a test
for the next week! :-)
73, Stefan/DK7FC
Am 29.10.2010 22:57, schrieb Jacek Lipkowski:
On Fri, 29 Oct 2010, pws wrote:
Yes, I'm very interested, especially in the makefile since I'm having
trouble invoking the GCC against those code. More than 30 years ago
dealing
with Fortran - on a block heating station named PDP-10 ["."]
the page with code and sample graphs is here:
http://www.lipkowski.org/~sq5bpf/vlf/wavevlf/
i've added a program that can be used to create data for graphs and
example files for gnuplot to make graphs. the code compiles under
gfortran
jacek
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