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Re: LF: 8269 kHz EbNaut tonight

To: [email protected]
Subject: Re: LF: 8269 kHz EbNaut tonight
From: Paul Nicholson <[email protected]>
Date: Tue, 26 Dec 2017 15:45:06 +0000
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Jan 2015 we managed 25 chars in 24320 seconds, this time 45
chars in 35050 seconds.  Actually just a small increase in
info rate from 20.7 bits/hour to 24.2 bits/hour.     On a lower
frequency this time and Dex's trees have grown some under the
antenna, so ERP will be a bit less.  Rx performance is improved
enough to just about compensates.

I don't know if we can get much more out of it, perhaps 46 chars
with 7 second symbols, or keep to 7.5 and extend duration in
both directions.  We're at about 70% of channel capacity and
EbNaut never does 80% or more, we might use 75% max.

> WX looks good for another run tonight.
> Maybe a short repeated message?

The only other site that might receive is Cumiana.  Based on S/N
from the 30 char message, it might do 3 chars 16K23A CRC20 with
30 second symbols 22:30 to to 06:30.  Have to use a weaker code
because the short message doesn't make full use of constraint
length 25.  I've extended the CRC to pad it out enough to fully
use constraint length 23 when using optimum list length.

If that got through it would be a record distance for EbNaut
decode but it might take a couple of attempts.

--
Paul Nicholson
--

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