Re: VLF: 8270.1 Sunday 16:10

[Markus Vester <markusvester@aol.com>]

Thanks Paul for trying! This message was really targeted at Stefan's receiver in Heidelberg, who has started saving 70 uHz spectum data for possible Ebnaut decodes.  But even there it would have been marginal. To make things worse, it started to rain here at 16:45; I had to go off air for about 10 minutes, and came back only with reduced.power. Running 0.27 amps (1 dB less) now, just below the onset of partial discharges.

 

I am now running another easier sequence:

 

Start time 18:30:02, 

5 characters, 8K19A, 16 bit CRC, 10 second symbols,

total duration 5120 seconds,

end time 19:55:22

 

TX frequency is 8270.1 Hz to minimize the effect of the local test during EbNaut sequences, and 8270.0025 for carriers in between.  

 

Well we'll see what we get...

 

73, Markus

 

 

-----Ursprüngliche Mitteilung----- 
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 24 Jan 2016 7:39 pm
Betreff: Re: VLF: 8270.1 Sunday 16:10

 

 > Frequency: 8270.1 Hz 

 > Start time 16:10:01 

 > Polynomial: 4K19A, CRC 16 bit 

 > 13 characters 

 > Symbol Duration: 10 s 

 

I wasn't able to decode this one here.  Signal calculator 

says it's probably a few dB too weak.  You would have to 

use at least 40 second symbols with that code and message 

length. 

 

Better to use 20 seconds and an 8K code (more constraints 

beats the increased symbol errors). 

 

10 seconds and a 16K better still if you can switch phase 

fast enough. 

 

Could not decode at Bielefeld or Cumiana either. 

 

-- 

Paul Nicholson 

--