Re: VLF: Coherent BPSK at 8270 from DF6NM

["Markus Vester" <markusvester@aol.com>]

Surely the concept is not limited to five-letter words. The current encoder implementation on Paul's website takes up to 50 characters, so you can announce a whole litter of kittens including their names, colours etc ;-) The coding for longer message actually becomes more efficient, due to a bit of fixed overhead (constraint length K, CRC check).

 

Although the transmit part is comparatively simple, the decoder is certainly not trivial. This is currently in an early state of experimentation, and I have no idea weather Paul  would really intend to take it all the way to an easy-to-use software package for everyday use.

 

Best 73,

Markus

 

From: DK7FC

Sent: Sunday, May 11, 2014 12:37 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: VLF: Coherent BPSK at 8270 from DF6NM

Hi Markus,

Uuuh, chatting with max. 5 characters will become difficult i think :-) As in JT-9, there should be 13 characters, so one can at least write "i have a cat"... :-)

Well, what does one need to arrange such a decoder? How is the message displayed? Is it possible to run a detection window, as a text file, like in OPDS?

73, Stefan

Am 11.05.2014 12:30, schrieb Markus Vester:

Stefan,

 

yes, you guessed right, the message content was indeed "DF6NM" ;-) Let me cite from a recent direct mail to Paul:

 

>> I was using a somewhat guessable message, foreseeing a possible "official first" demonstration. Maybe a truely random message would have looked even more impressive ;-) Anyhow as this is formally not "amateur radio" but rather using an unallocated frequency range, so there's no need for an allocated callsign. Maybe if you'd set up a transmitter (relatively easy) and I'd learn how to decode (the hard part), we could start chatting away on VLF ;-)

 

73, Markus

 

From: DK7FC

Sent: Sunday, May 11, 2014 12:06 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: VLF: Coherent BPSK at 8270 from DF6NM

Hello Paul, Markus,

Well done! Interesting stuff. I see you never stop to find some new
things to try :-) Well well, i should think about...

What was the contest of the message? A complete callsign, DF6NM?

73, Stefan

Am 11.05.2014 08:36, schrieb Paul Nicholson:
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