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Re: ATV from Space?



There are two problems due to frequency allocations. The uplink band is 10
MHz wide and amateur FM FSTV is 17 MHz wide. The downlink band is 3 MHz wide
and AM FSTV is 6 MHz wide.

Digital video would require less power than analog video and PCs can do the
necessary compression. It seems that a 384 kbps digital transponder would be
a better investment as this speed supports streaming video over the
Internet.

73,

John
KD6OZH

----- Original Message -----
From: "Dee" <morsesat@optonline.net>
To: <amsat-bb@amsat.org>
Sent: Thursday, December 29, 2005 19:47 UTC
Subject: Re: [amsat-bb] ATV from Space?


> Robert Bruninga wrote:
>
> >I'd like to form a core design group to design
> >a satellite Amateur TV repeater.  Everyone knows
> >this wont work unless the satellite has lots of
> >power (far beyond our usual power budgets).
> >
> >But what if there was a launch opportunity that
> >had 100 watts or more power available?
> >
> >I'm in the middle of a lunch campaign and dont
> >have time right now to work up a link budget,
> >but thought some others might enjoy looking
> >at the problem.
> >
> >1) Assume ranges of 1500 km
> >2) Assume 100 watts DC average power
> >3) Uplink FM on 1.2 GHz band
> >4) Downlink VSB FSTV on 70 cm band
> >
> >Someone want to work it up and address all
> >the issues of bandwidth, coordination,
> >compatibility, etc...
> >
> >Goal would be anyone with a cable ready TV
> >to see signals using maybe the gain of a
> >handhled Arrow antenna for downlink?
> >
> >Bob, WB4APR
> >US Naval Academy Satellite Lab.
> >----
> >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!
> >To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> >
> >
> >
> Bob,
> It's funny that you suggest this but many times have I said the same
> thing. Kids, the future of our hobby, are certainly more visually
> impacted vs. a few beeps and squeaks from a black box.  Problems with
> your suggestion.  LEO and not HEO.  I must again explain that fleeting
> satellites do not draw support.  99+% of people (My unscientific polls)
> want HEO satellites and while opportunities for putting together a LEO
> satellite are more numerous, a 10 minute pass is not conducive to any
> type of  TV work.  Also, 2.4ghz and 1.2 ghz would be the preferred
> freqs.   With my limited time to operate a satellite, LEO's aren't there
> when I am the majority of the time. I've been successful with the LEO's
> many, many times but we need a longer visibility window to give people a
> chance to experiment and more operational time.
> My time spent representing AMSAT at hamfests and presentations etc. have
> resulted in the same common thread- satellite enthusiasts have been
> spoiled by OSCAR 10, 13, and 40.  The bottom line is funding and HEO's
> is what the squeaking wheels keep above the noise.
> Your idea of a TV repeater is a good one, however, it must be visited
> with the hopes of attracting a larger audience for financial reasons.
> 73 & Happy 2006,
> Dee, NB2F
> P.S.  I've never had a lunch campaign that was that long!!??!!!(Hi, Hi!)
> ----
> 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!
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
----
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!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



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