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Re: VLF: tonite on the 36km band...

To: [email protected]
Subject: Re: VLF: tonite on the 36km band...
From: DK7FC <[email protected]>
Date: Fri, 05 May 2017 15:12:42 +0200
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Thanks Paul, all,

Transmission for Paul only was meant in that way that you are probably the only one who get the necessary Eb/N0 for a decode. But now DL0AO is using a better antenna, they may also reach the threshold, providing the FFT length covers 13:44 hours...
I see again that a high VLF mailing activity seems to lead to a lower
LF/MF mailing activity. But why? The bandwidth isn't limited.
73, Stefan

PS: > 50 % of the 100 char message is already out...

Am 05.05.2017 09:56, schrieb Paul Nicholson:
Stefan reported a problem with setting message
length in the v0.7 decoder.  Now the version
is 0.7a which fixes this problem:

Stefan wrote:

Probably that's a transmission for Paul only:

> f = 8270.100000 Hz
> Start time: 05.May.2017   05:30:00 UTC
> Symbol period: 10 s
> Characters: 100
> CRC bits: 0
> Coding 8K19A

Needs about 5 Gbyte RAM to decode when using list length
of one million, about 7 Gbyte for two million.

It's likely that using the 8K19A instead of the stronger
16K21A will work better for some given available RAM,
because the small loss of coding gain in the convolutional
code can be more than made up by the use of a longer

An interesting 'feature' of longer messages is that a
false decode is often only partly false - you may find
most of the message is correct but there is a garbled

Paul Nicholson

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