AW: Re: LF: 8270 Hz traces again! AK

[uwe-jannsen@kabelmail.de]

rain agn. the transmission has been switched off at 21:06:42.

what abt the second message 20:01 until 21:02 ?
can you decode that one?

Uwe/dj8wx

 

Von: Paul Nicholson <vlf0403@abelian.org>
Gesendet: 08.12.2015 21:53
An: <rsgb_lf_group@blacksheep.org>
Betreff: Re: LF: 8270 Hz traces again! AK

 

Carrier of DJ8WX measured in about 80uHz bandwidth. S/N is 18.4dB in
this bandwidth.

http://abelian.org/vlf/tmp/151208a.gif

The magnetic flux density of 0.1fT corresponds to around
30nV/m electric field strength.

Uwe wrote (28th Nov)

> Coding 8k19a
> Characters 2
> Bits 368
> Duration 01:01:20.00
> Start 2015-11-28 17:00:00
> Rpt on hour
> (in between carrier only)

With the above S/N, this should decode at about Eb/N0 = +2.5dB

Uwe wrote (today)

> carrier on the air.
> the message starts at 18:00:00

At 18:00 I am still getting carrier. When I run this into
the decoder it struggles to decode, the noise has come up
since the S/N measurement. I add in the E-field to gain a
couple of dB and then the carrier decodes:

18:00:00 to 19:01:20
found rank 0: ** ps [ 2 30 30 30 30]
re-encode 131/368 ber 3.56e-01 Es/N0=-11.6 Eb/N0=3.3

(Carrier decodes to a string of * characters).

--
Paul Nicholson
--