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Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz

To: [email protected]
Subject: Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz
From: DK7FC <[email protected]>
Date: Sun, 29 May 2016 15:42:34 +0200
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Hi Paul,

What about your results? Nothing? 2 Remaining chances for a message.
I would expect the 13 char message should have decoded.
Do you still like playing the VLF experiments, or do you need a break?

73, Stefan

Am 25.05.2016 03:04, schrieb DK7FC:
Hi Paul,

The message just finished. The next one starts 4 UTC. Just in case the 68 hour message does not decode, i'm trying to continue in smaller steps using a day-night-day period of 36 hours:

f = 6470.00000 Hz
Start time: 25.05.2016   04:00:02 UTC
Symbol length: 140 s
Characters: 13
CRC 16
Coding 8K19A
Duration: 34h, 50m, 40s

Antenna current: 250 mA

73, Stefan

Am 21.05.2016 17:52, schrieb DK7FC:
Hi Paul,

Thanks! The message is correct. Our longest message so far on 6470 Hz :-)

The WX forecast is no ideal for the next days: Rain! My transductor variometer is still not automatised and its tuning range is a bit small. So probably it is not possible to hold the antenna current during rain. I also saw that the losses are higher when it's wet, makes a difference of about 10%, i.e.  -0.9 dB.
With a stable antenna current of 250...260 mA and low QRN it could be possible to make the 20 character message with 100s symbols, into a day-night-day period. However this will be hard in the coming days.
So i better prepare for 200s now:

f = 6470.00000 Hz
Start time: 22.05.2016   04:00:02 UTC
Symbol length: 200 s
Characters: 20
CRC 16
Coding 8K19A
Duration: 2d, 20h, 26m, 40s

Antenna current: 200...260 mA (Rain!)


73, Stefan


Am 21.05.2016 04:15, schrieb Paul Nicholson:
Stefan wrote:

> f = 6470.00000 Hz
> Start time: 20.05.2016   00:30:02 UTC
> Symbol length: 100 s
> Characters: 10
> CRC 16
> Coding 8K19A

Copied 'THAT WORKS'

Eb/N0 = +2.7 dB, constant reference phase

Carrier: 19.25 dB in 13.3 uHz

Error map: http://abelian.org/vlf/tmp/160520a.gif

--
Paul Nicholson
--

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