Re: ULF: EbNaut message transmitted from ground loop

[DK7FC <selberdenken@posteo.de>]

Am 07.04.2019 01:10, schrieb DK7FC:
> Wow, amazing! We've done it :-) 7 characters in 2 hours at ULF. A 
> first message from DL > UK.
> Think about how long we needed to TX and stack for the 14 dB SNR 
> spectrum peak 2 years ago.
From Pauls milestone list i see that for the 2970 Hz carrier detection 
in March 2017, we needed 99 hours to integrate in one bin. Now wee 
needed 2 hours for 17 dB, i.e. 1 hour for 14 dB. So we are 99 times 
faster now, almost a 20 dB stronger signal!
I remember that it took 100 hours to wind the 6.1 H loading coil for the 
E field antenna, and its livetime was not much longer than 100 hours! It 
was much more expensive than the wire for the ground loop. Beeing close 
to (to close!) the voltage limit of the coil i was unable to run more 
power. Now, there is room for another 6 dB at this antenna, easily.
Oh, and another important point: The bandwidth of the loop is much much 
higher! It would allow to transmit on two frequencies for example, to do 
propagation research at ULF...
73, Stefan