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Re: AO-7 Emergency receiver



Make that a 1460 km orbit as Oscar 6/7 but yes thats basically what we need 
- a simple straight forward communications satellite using Mode A or B 
LINEAR transponders that ordinary hams with modest stations (50-100w EIRP) 
can use for SSB/CW QSO's.

I just don't understand why AMSAT-NA are persisting with a single channel FM 
voice repeater - its not whats wanted.

Trevor M5AKA

>From: "Graham Shirville" <g.shirville@btinternet.com>
>To: "SM0AIG" <sm0aig@hotmail.com>, <Richard@g3rwl.demon.co.uk>,   
><amsat-bb@AMSAT.Org>
>Subject: Re: [amsat-bb] AO-7 Emergency receiver
>Date: Fri, 28 Jun 2002 21:43:15 +0100
>
>We should remember that not long after Oscar 7 and 8 AMSAT volunteers
>developed a wonderful method of matching Nicads to prevent this sort of
>problem.
>
>Hence Oscar 11 with it's batteries still performing after 20+? years.
>
>The amazing thing is that almost all of the rest of the hardware still 
>seems
>to be working.
>
>So after all the recent debate are we really saying that the most popular
>spec for a new Oscar would be a 10 watt Mode B bird in a  1200km sun
>synchronous orbit with little if any software/ICs and a damn big solar
>array?
>
>Well it looks like there will be plenty to discuss/debate at the AMSAT-UK
>Colloquium next month in Guildford!
>
>Please excuse the plug and check out
>
>http://www.uk.amsat.org/colloquium.htm
>
>73 all
>
>Graham G3VZV
>
>----- Original Message -----
>From: "SM0AIG" <sm0aig@hotmail.com>
>To: <Richard@g3rwl.demon.co.uk>; <amsat-bb@AMSAT.Org>
>Sent: 28 June 2002 19:13
>Subject: Re: [amsat-bb] AO-7 Emergency receiver
>
>
>The fact of the matter is that with an emergency receiver we wouldīnt have
>to send up new satellites every second year so I donīt think there would be
>a problem of frequency congestion. Itīs just such an utterly waste of time,
>money and effort to have a completely healthy satelite killed off by some
>stupid battery short - a problem that could certainly be addressed one way
>or the other. And if one would plan for a future on solar power only, the
>satīs behaviour would not be as erratic as that of todayīs Oscar 7.
>
>Maybe the designers at the time never realized that solar cells might have 
>a
>life span of 30 years or more. Yes, this is truly a matter worthy of some
>debate.
>
>Oscar 7 also has a near-perfect orbit for a LEO, at least on our latitudes.
>It appears over the Stockholm horizon 10 times a day from 6 am to around 11
>pm in 20 minute passes. That amounts to three hours of daily operating 
>time.
>And it stays that way until Xmas Eve both this and the next year.
>
>Ingo / SM0AIG
>
>Original Message -----
>From: "Richard W L Limebear" <Richard@g3rwl.demon.co.uk>
>
>
> > "SM0AIG" writes:
> >
> > > And the s/c
> > > would live happily ever after, singing to us for decades.
> >
> > /Heresy mode ON
> >
> > But do we really want them all to stay on. Really. All of them. Sure,
>theres
> > some candidates for this (with 20/20 hindsight) but I'm not totally
>convinced
> > this would be a good idea. For a start we'd run out of frequencies for 
>any
> > new birds.
> >
> > /Heresy mode OFF
> >
> > Could make an interesting debate.
>73
>Richard W L Limebear G3RWL
>
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>
>----
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Trevor M5AKA


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