[aprssig] aprssig Digest, Vol 148, Issue 8

Dave B g8kbv at uku.co.uk
Tue Oct 11 03:41:09 CDT 2016


27dB is 500 times, not 1000.  Only half an S point in it, but...

As Bill Vodal suggested, one of the JT modes (Jt9 is very narrowband
too) could be good.  But frequency stability is a significant
requirement for some of them as a result of the narrow band factor, and
long transmission time..

73.

Dave G0WBX


On 10/10/16 18:00, aprssig-request at tapr.org wrote:
> Subject:
> [aprssig] APRS-WSPR APRS from anywhere!
> From:
> Robert Bruninga <bruninga at usna.edu>
> Date:
> 09/10/16 20:20
>
> To:
> TAPR APRS Mailing List <aprssig at tapr.org>
>
>
> The more I think about it the more I get excited about building up an
> APRS-WSPR Gateway system.  With the 27 dB signal processing gain of
> WSPR, then a 1W transmitter is the same as 1000 watts.  And for
> receive, since APRS can have HF receivers everywhere, then this can
> really expand the usefulness of APRS anywhere in the world including
> on the fringes of our existing network.
>
> QST in September showed the $29 TAPR WSPR daughter board that plugs
> onto a Rasberry pi and although it is only a 100 millliwatt
> transmitter, with enough WSPRgates, that should not be a problem.  But
> adding a 1W PA will always help!
>
> I already have come up with a compression technique that can improve
> on the existing gridsquare (60x120miles) down to (18x12miles) and down
> to 3 miles or nearly a half mile for 5 and 4 letter calls.
>
> see http://aprs.org/aprs-wspr.html
>
> Lets get those WSPR boards on the air!
>
> Bob, WB4APR

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