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Re: Re: Ham Radio High SPeeed data



There is an article on the D-Star system in the latest issue (June) of Radio 
Active magazine (UK publication).

Trevor M5AKA

>From: Phil Karn <karn@maggie.ka9q.net>
>Reply-To: karn@ka9q.net
>To: bruninga@usna.edu
>CC: amsat-bb@AMSAT.Org
>Subject: [amsat-bb] Re: Ham Radio High SPeeed data
>Date: Mon, 20 May 2002 11:10:00 -0700
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>
>A google search for "jarl d-star" yields quite a few hits, but all of
>the pages so far are in Japanese only.
>
>From what little I've seen, the system looks promising but my big
>concern is that the physical layer may not incorporate any coding. It
>*appears* to be just uncoded GMSK.
>
>This is corroborated by the sensitivity figures in Icom's Dayton
>handout. The digital modulation requires more microvolts than FM,
>while a well-coded signal should require less.
>
>This affects not only the required transmitter power, but also the
>interference susceptibility and the amount of interference that is
>created for others. And it affects the ability of the system to
>withstand fading, impulse noise and multpath.
>
>Phil
>
>
>
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