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LF: Re: RE: <Tech> Wolf coding

To: [email protected]
Subject: LF: Re: RE: <Tech> Wolf coding
From: "Vernall" <[email protected]>
Date: Wed, 2 May 2001 08:35:45 +1200
References: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
Andy and others,

re Jim's comments :

>  I have been thinking along similar
> lines for somewhat different reasons. I don't claim to have
> expertise in this field, but suppose the data rate of Wolf was
> reduced by a factor of 10, ie, to 1 bit per second. What would be
> the effects?
I was not proposing just slowing Wolf down, I was arguing the merits of
using Uncoded BPSK for the same performance  (a-la VE2IQ & Coherent) but
at 1 b/s - this would give a few extra dB capability immediately.  With
Wolf coding as well, this could give 10 dB extra but at 16 minutes for a
15 character message.
I suggest that there are also middle options.  At LF there are "lightning
pops" and some forms of QRM that are that are "bursty", and either could
thwart successful decoding of a few parts of a message, but inbetween noise
bursts the RF S/N conditions could be satisfactory for reception.  So having
some redundancy is desirable, especially for a text messaging system.  The
question is in the selection of the degree of coding overhead.  I do not
have a suggestion as to where the optimum answer lies.

73, Bob ZL2CA

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