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Re: New AO-27?



30 minute passes are possible. Rs-15 was launched by an old Russian ICBM and
is in a 2000 km orbit that provides up to 30 minute passes. There is 8 dB
(9X) more path loss than a traditional LEO orbit at 800 km so you need more
uplink power. The lifetime of the satellite may be less at this altitude
because of increased radiation but it may be a reasonable compromise.

On 435 MHz with an omnidirectional antenna 15 watts would be the minimum
required on FM so a 25 W mobile radio could easily be used. A 5 W HT would
need an Arrow antenna to use the satellite. This type of satellite would be
much bigger than the current microsats because of the larger amount of power
required. Only a few FM channels can be reasonably accomodated but a much
larger number of end user digital voice channels could be made available as
availability permits.

73,

John
KD6OZH

----- Original Message -----
From: <sco@sco-inc.com>
To: "John Stephensen, KD6OZH" <kd6ozh@amsat.org>
Cc: <amsat-bb@amsat.org>
Sent: Sunday, 24 December 2000 12:29 UTC
Subject: Re: [amsat-bb] New AO-27?


> At 12:41 AM 12/24/2000 , you wrote:
> > > PCs get more powerful and less expensive all the time. Why should a
ham
> >sat
> > > cost more?
> >
> >The electronics in either a geosynchronous or Molniya orbit ham sat are
> >getting less and less expensive. However, the cost of the rocket engine,
> >fuel, spaceframe, electrical power generation system and launch vehicle
> >haven't come down in cost very rapidly at all. The number of satellites
> >manufactured is miniscule compared to the numbers of PCs that are
> >manufactured.
> >
> >The only type of satellite to benefit significantly from the
manufacturing
> >volume of PCs and other personal electronics is a low earth orbit (LEO)
> >satellite because it eliminates many of the low-volume "rocket-science"
> >components. Launch costs for this this type of satellite have also come
down
> >recently because the Russians have a lot of old ICBMs to get rid of and
they
> >are only useful for launching LEOs.
>
> THEN Could we get a LEO bird into a little higher orbit so we have at
least
> 30-45 minutes on a pass?
> This could be either a FM bird [2m up/70cm down] or a SSB/CW sat [that
> could work with the new Ft-817 ???]..
>
> W4SCO
>
>

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