Re: [amsat-bb] Digital SSB Mode, Laser over satellite

["John B. Stephensen" <kd6ozh@xxxxxxxxxxx>]

Digital voice adapters for SSB radios are OFDM modems with 48 modulated carriers
spaced 62.5 Hz apart. The crest factor is similar to SSB so they should work
over a linear transponder. However, the modem must be right on frequency or you
hear nothing. Tracking Doppler shift will be be a problem.

73,

John
KD6OZH

----- Original Message -----
From: "Mike Hooles" <Mikehooles@btinternet.com>
To: "AMSAT" <amsat-bb@AMSAT.Org>
Sent: Saturday, 07 August, 2004 09:00 UTC
Subject: [amsat-bb] Digital SSB Mode, Laser over satellite


> Hi Folks,
> Just to keep us forward thinking.
> 1. Before I buy a unit, has anybody tried digital SSB on FO29 yet?
> What is the likely impact of this mode over the satellites?
>  In practice,  is it going to hit the satellite power supplies significantly
> harder than normal SSB?
> and should we start thinking about this as a separate mode for the future?
>
> 2. How about setting up a nominal standard for ground to satellite laser
> communications, e.g. green ? nanometers up and red ? nanometers down, just
> to get us started. We can modify them later.
> From point to point results already obtained in Europe and the U.S. it
> looks as though  we can get to the LEO's with 5mW ( maximum pointer legal
> power) without too much difficulty.
>
> Regards
> Mike G3LGR
> ----
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