Stefan,
Excellent news, a great day for ULF!
1570 Hz seems like rough propagation terrain (unpredictable spatial nulls
and temporal phase variations at distances less than 500 km); I wonder if
the earth-loop antenna magnetic field pattern helps with these.
It seems that the rough part of ULF is yielding to your experimental
adjustments and innovation, well done!
Regards,
Jim AA5BW
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of DK7FC
Sent: Wednesday, September 5, 2018 8:51 AM
To: [email protected]
Subject: ULF: First far field detection at 1570 Hz
ULF,
Last sunday i finally managed to detect a carrier transmission on the
191 km band in the far field. In fact the distance is higher than 1/4
wavelength. A new lowest frequency of a signal generated by amateurs,
detected in the far field.
At 250 W RF power i transmitted for 2 hours (starting 08:08 UTC) on my 900m
long ground loop antenna. It seems to be a very hard band with poor
propagation. Furthermore my RX antenna becomes deaf below 2 kHz. So the S/N
is much lower as expected when comparing to the results at 1970 Hz.
Two spectrograms are arrached, showing the short trace in 424 uHz and
212 uHz.
Before finally entering the far field in the frequency range below 1 kHz it
may be necessary to build up an E field RX at the RX QTH. I first step for
that was done yesterday.
To be continued...
73, Stefan
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