[amsat-bb] Re: Phase 4 versus Eagle

[sco@sco-inc.com]

"WE" will be where our "host" is located and need to point from there 
the best we can. I assume we will know this info before launch? So 
whether or not we can aim for a certain spot is unknown until then.

At 02:59 PM 12/14/2007, you wrote:
>Probably a good pointing spot would be where XM and Sirius Point their
>antennas - just about on the Canadian Border close to Winnipeg- Manitoba
>73
>Robin VE3FRH.
>
>-----Original Message-----
>From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
>Behalf Of Edward Cole
>Sent: December 14, 2007 1:43 PM
>To: Andrew Glasbrenner
>Cc: amsat-BB
>Subject: [amsat-bb] Re: Phase 4 versus Eagle
>
>Drew,
>
>I have direct personal experience with this when I was a TVRO
>installer up here in Alaska.
>
>Before the mid-1980's TV-satellites pointed their antennas at mid
>America around Kansas - Nebraska.  Due to Alaska being not only at
>the far northern fringe but also western edge of the beam, signals
>were down around 6 to 10 dB (from memory).  This meant that to
>receive the signal in Alaska one needed at minimum a 12 to 14 foot
>dish.  IN Barrow (Lat=70) it  took 16 to 20 foot dishes pointed a few
>degrees above the horizon (7-deg max due south).  As time went on the
>satellite industry re-pointed some of the satellites to better favor
>Alaska and Hawaii resulting in being able to use 8 to 10 foot
>dishes.  Today we get ku-band sat-TV with the use of a 30-inch dish
>(you use an 18-inch dish in the lower-48).  We find that we need a
>1-1.2 m dish to overcome rain/snow fading, though.
>
>OK how does this relate to P4?  For far-north or far-south stations,
>it will require careful ham station antenna location that can see a
>clear low horizon elevation angle and probably more antenna gain to
>overcome being on the fringe of the satellite antenna
>"footprint".  If the sub-satellite (straight down) position on the
>equatorial orbit is too far east or west of one's local longitude,
>there will be no view above the horizon for the extreme latitude stations.
>
>This will have no technical cure.  So hopefully the orbit positions
>that can be obtained will be favorable to the maximum population.  I
>would expect P4A and P4B will ride to mid-America and European
>positions.  The Pacific sat probably would be the last launched if
>one were trying to reach the maximum ham population centers (only logical).
>
>So you can see why Alaskan satellite operators are hoping for the
>launch of P3E and Eagle.  Otherwise we may be in for a long wait till P4C!
>PS:  I'm taking the liberty of assigning the designations P4A, P4B,
>P4C (not AMSAT terminology).
>
>Following the saga with interest - and hope!
>73, Ed - KL7UW
>
>At 08:50 AM 12/14/2007, Andrew Glasbrenner wrote:
> >I noticed the new release of SATPC32 12.7 includes Intelsat
> >spacecraft in one of the keplerian/satellite options. You can scroll
> >through them and get an idea of the possibilities and range of
> >footprints. Real life performance will be, as Bob suggests,
> >dependent on our antenna pattern. Other services are usuable from
> >the poles, such as Inmarsat, given enough gain and a clear horizon.
> >MTI uses this as a selling point for their phone with the 4 ft
> >dishes we S-band types are so fond of. So we might work fairly well
> >out to the edge, again, dependent on the antenna.
> >
> >73, Drew KO4MA
> >
> > >From: Robert McGwier <rwmcgwier at gmail.com>
> > >
> > >We do not know the answer yet.  Our request is for multiple payloads,
> > >covering with subsat over Atlantic, Pacific, and Central U.S.  We would
> > >need one over the Indian Ocean to cover the 2 pi radians of the equator
> > >with antenna pattern.  The north and south pole would be left out so I
> > >am sure the emperor penguins and polar bears would be upset!
> > >
> > >Bob
> > >
> > >Simon Brown wrote:
> > >> Where would this GEO be positioned? Even rough information would be
> > >> interesting.
> > >>
> > >> Simon Brown, HB9DRV
> >
> >
> >
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>
>73,
>Ed - KL7UW
>======================================
>   BP40IQ   50-MHz - 10-GHz   www.kl7uw.com
>144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w
>DUBUS Magazine USA Rep dubususa at hotmail.com
>======================================
>
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