[Lowfer] Re: Modes, signaling, and data recovery

[Les Rayburn]

Very exciting to think about Alberto and Stewart joining
forces on a piece of software, esp. one that will offer
something for us weak signal types. If we could Bill de Carle
to join in, we might really be onto something!

One thought about repeating messages. I don't consider it
cheating if you know the message length. It still does not
provide you with the intelligence contained within the message...

My understanding that having the software be aware
of the message length makes a big difference in
it's ability to detect weak signals. Also, with the addition of
the GUI interface, I'd expect to see very "creative" messages
such as we have seen in Jason mode here this season.

Please keep us posted and I repeat the offer for financial assistance.

73,

Les Rayburn, N1LF




>Hi Stewart and the group,
>    I read with interest your comments and proposals for an evolution of
>the protocols used in LF weak signal operations.
>If I understand well your scheme, you suggest to use absolute frequencies
>as signalling elements, or maybe delta frequencies, as in the present Jason,
>could be used ?
>The synchronizing pattern seems to be a good idea, but do we really need
>four synchronizing symbols ? Aren't they an overkill ? Just asking.
>
>I have another comment on the decoding of repeating messages. Of course,
>this is just personal opinion, but I feel a bit like cheating if I have to 
>give
>as input to the program the expected length of the message. However, I do
>realize that this is needed if you want to do an integration over a long 
>period,
>without using a brute force approach, trying all the possible lengths, and
>probably this is the only way to achieve (together with GPS synch) a
>possible transatlantic reception of a lowfer signal.
>
>You say : "Who will write all this software ?". The answer is not easy, as,
>if fully implemented as you describe, it's not a minor task. You offered for
>the sigproc part. We could tentatively start a joint effort (with no
>guarantees..:-), where I could invoke an entry point of a DLL produced by
>you, passing you a pointer either to the time-domain series of values
>obtained by the sound card, or to the frequency-domain FFT-processed
>output of those values, or a decimated series. We just have to agree on the
>details. In return, you could pass me back some status flags and a decoded
>data block. But from now on maybe we could continue via private emails.
>
>Let me please know your thoughts,  TNX
>
>73  Alberto  I2PHD
>
>
>
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Les Rayburn, director
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