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Re: LF: VLF/ULF activity weekend 21th/22th

To: [email protected]
Subject: Re: LF: VLF/ULF activity weekend 21th/22th
From: DK7FC <[email protected]>
Date: Mon, 23 Jan 2017 19:17:36 +0100
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Am 23.01.2017 18:52, schrieb Paul Nicholson:
> What do YOU need to get a first trace of my signal in the UK?

Perhaps I need to move 1/2 wavelength nearer or further?  Maybe
the sky wave and ground wave are just nicely cancelling out?
Maybe, yes. But then a night transmission could show another result! The DFCW-10800 message could be combined as well. It was transmitted during the night:
DFCW-10800, message 'F' = dit dit dah dit
dit: 17...20 UTC
dit: 21...0 UTC
dah: 1...4 UTC
dit: 5...8 UTC

dit: 2969.9975 Hz
dah: 2970.000 Hz

> Would you do the decode work for me if i try to leave my
> call over 3 wavelengths on ULF?

Sure.  Your chosen settings look OK so long as the signal
at Bielefeld is as good as the 21st.  It doesn't seem very
repeatable, Friday 20th signal was not so good - 6dB weaker
and with a large phase difference too.  162 degrees on 20th
and 63 degrees on 21st.  But on 20th there were three occasions
when the Bielefeld timestamp stepped backwards by one sample,
which adds up to the extra 100 degrees.  Probably accounts
for the 6dB loss too.

So give the 5 chars a try.  If there are not too many timing
glitches I can probably adjust for them.
Maybe the reason is the QRM level? Maybe there is less QRM during the weekend? This could be another relevant factor.
The QRN was much lower today relative to Saturday. Maybe i should try a shorter message first, just to get some more experience.
Let me try:

f = 2970.000000 Hz
Start time: 24.Jan.2017   08:00:00 UTC
Symbol period: 30 s
Characters: 3
CRC bits: 18
Coding 16K25A
Duration: 8h, 0m, 0s
Antenna current: 150 mA

That's quite comfortable, i just realise that i can make ULF transmissions now, whitout the need to leave the warm building. Same for you, same for Wolf! :-)

73, Stefan

PS: Unfortunately i overwrote my txt file for the 100 character message on 5170 Hz and i even forgot the message! But i have saved txt files that should contain the message :-) So i need to decode it to know the message again. I tried together with DL6II but even 16 GB RAM were not enough. How much RAM does one need to deocode that message? The list length can be very small because the message should decode at rank 0 within the first phase pattern attempts...

Paul Nicholson

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