Message-ID: <58701056.20008@posteo.de>
Date: Fri, 06 Jan 2017 22:47:02 +0100
From: DK7FC <selberdenken@posteo.de>
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In-Reply-To: <5870097B.7080708@posteo.de>
Subject: Re: VLF: Back on 5.17 kHz / 58 km...
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PS: Was the message decodable in Italy as well? Would be interesting to 
see if Renato got it too. I don't want to cause to much work to you, so 
only check it if you like. I don't even know how much effort that makes. 
Maybe you have a Linux script for each task and this question means just 
typing a single command line(?).

73, Stefan

Am 06.01.2017 22:17, schrieb DK7FC:
> Hi Paul,
>
> The errors in the 0 0 0 0  error map look quite equally spread.
> How much weaker is the average night signal relative to the day 
> signal? If the difference is not much, it would be worth to use the 
> nights as well.
>
> I got the feedback that the message was not decodable on the other 
> station, unfortunately. So maybe the plain carrier which is running 
> since 12 UTC is more helpful. It is already visible in Italy again: 
> http://www.vlf.it/cumiana/livedata.html
> Now, what was the message? :-)
>
> My signal looks terrible on the tree grabber. I still don't know the 
> reason. Is it the TX or the RX? The TX PC is very old. I thought it 
> could be a temporary overloaded USB port (WLAN + USB soundcard), so i 
> tried a LAN connection instead, with no change. Another thing could be 
> partial discharges in the coil arrangement! So i reduced the antenna 
> current from 21 UTC to 21:30 UTC from 225 mA to 210 mA. So far there 
> is no significant change. At 21:30 i will go down to 180 mA. If this 
> makes no difference i will go back to 225 mA again at 22 UTC. I will 
> run the carrier until tomorrow evening. Then i may have a new idea 
> what we could do next, on 58 km.
>
> The next 2.97 kHz experiment is a bit delayed but the coil is ready 
> for 150 mA. They say the wx will be terrible in the next days but as 
> soon as there are a few good days, i will be back on 101 km...
>
> 73, Stefan
>
> Am 06.01.2017 12:33, schrieb Paul Nicholson:
>>
>> Stefan wrote:
>>
>> > f = 5170.000000 Hz
>> > Start time: 04.Jan.2017   08:00:00 UTC
>> > Symbol length: 60 s
>> > Characters: 8
>> > CRC 16
>> > Coding 16K25A
>>
>> > I will repeat the transmission starting [5th] 8 UTC...
>>
>> Best decode with reference phase pattern: 30 30 0 0
>>
>> Eb/N0 = +3.6 dB,   BER 35.0%, list rank 0.
>>
>> S/N 20.24 dB in 11.8 uHz,  -63.0dB in 2.5kHz
>>
>> The phase pattern is appropriate for an advance of the
>> signal phase during day relative to night.
>>
>> Symbol error map (with 30 30 0 0 pattern):
>>
>>  http://abelian.org/vlf/tmp/170106a.png
>>
>> and with constant reference (0 0 0 0 pattern)
>>
>>  http://abelian.org/vlf/tmp/170106b.png
>>
>> Not much difference, 500/1408 symbol errors with constant
>> reference.  Down to 493/1408 with 30 30 0 0 pattern.
>>
>> I haven't mentioned the message text because it's possible someone
>> else may be trying a decode.
>>
>> > that  makes a fine record of 5.17 kHz successes
>> > between the two of you!
>>
>> Indeed, 5170Hz seems to be quite a cooperative band to use.
>>
>> -- 
>> Paul Nicholson
>> -- 
>>
>