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Fw: Re: Digital SSB Mode, Laser over satellite



I forgot to send the query to the BB , John.
I thought it best to includ the community.

Joe  K0VTY
=======================
--------- Forwarded message ----------
From: k0vty@juno.com
To: kd6ozh@AMSAT.Org
Date: Sun, 8 Aug 2004 12:40:20 CDT
Subject: Re: [amsat-bb] Digital SSB Mode, Laser over satellite

Hi John

What happens with the OFDM when multi SSB signals are involved ?
Say a worse case would be a SSB DX pileup.

Joe  K0VTY
==============================
On Sun, 8 Aug 2004 04:11:35 -0000 "John B. Stephensen"
<kd6ozh@verizon.net> writes:
> 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
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the 
> author.
> > Not an AMSAT member? Join now to support the amateur satellite 
> program!
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> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the 
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