Am 28.04.2016 20:28, schrieb Paul Nicholson:
Stefan, want to try EbNaut at a lower frequency? That would
be a good challenge. 6kHz perhaps?
Paul, maybe you are right! We don't know so much about the propagation
and phase stability on lower frequencies. If we assume the phase is much
more stable on lower frequencies then 8.27 kHz, then it may be worth to
experiment there, in slower modes.
The most important system is, in my opinion, that stable transmissions
can be done at any time!
I sent 45 characters to you over 850km distance within 24 hours. 24
hours is nothing! It could have been 4 days, no problem!
I still have 2 yoghurt cups ready to be added to the coil, no problem to
go down another kHz.
And i've ordered these 100x 3C85 cores! I'm really looking forward to
experiment with them. With these cores it will be no problem to go down
to 4 kHz. The question is which antenna current i can get with them.
Maybe even 3 kHz is possible.
Oh yes, let us try 2.97 kHz, OK? That's ULF! Sounds not realistic? A
dream into a dream, you know?!
2.97 kHz, that's a distance of just 1.7 lambda to DF6NM and 8.8 lambda
My antenna has 114 kOhm reactance there, so 150 mA is no problem. That's
about -5 dB over the current current. The radiation resistance falls by
another 9 dB. So the signal will be 14 dB weaker? Sounds managable.
Sferics are weaker below 5 kHz or so. Is it just due to propagation and
will a amateur radiated signal over < 1000 km suffer from the same loss
in propagation so the SNR stays the same, apart from the weaker signal?