[amsat-bb] Re: Phase 4 versus Eagle
kl7uw at acsalaska.net
Tue Dec 11 21:24:58 PST 2007
At 04:06 PM 12/11/2007, Tony Langdon wrote:
>At 11:21 AM 12/12/2007, Patrick McGrane wrote:
> >Merry Christmas to all my fellow space enthusiasts
> >Nice to see some informative Big Picture discussion here.
> >For all its worth; I believe a cooperative effort with an
> >established satellite builder incorporating an auxilliary payload
> >makes more sense than an independant effort with more complexity and cost.
>Agreed, more efficient use of resources.
> >Who really would'nt want a geosynchronise transponder?
>One? Probably not (odds are it would be parked over the Atlantic, a
>useless location from here). 2 or 3? Definitely (global coverage,
>except near the poles).
>73 de VK3JED
Good points! Most of you probably do not realize that geostationary
satellites are not high in the sky from high latitudes. From my QTH
(60.7 degrees north) the maximum elevation angle to the Geostationary
orbital plane (also called the Clarke Belt) is 21 degrees. That is
to a satellite positioned over the latitude of Hawaii (Longitude
150). If the satellite is parked too far east or west, it will be
below the horizon to us. That is true equally to north and south hemispheres.
I have written this before. The reason the Phase-3 satellites were
so popular was that they were in highly inclined orbits (to the
equator). Geostationary orbits are not inclined at all (ideally zero
This does not mean I am apposed to P4A. I am thoroughly in favor as
it is a great opportunity. But designers do need to realize the
impact for access to them (and I am sure they are aware). The rest
of you need to think about it to see the difference it will
make. NZ, AK, Aust. and Japan all will only be able to access a
Pacific satellite. DX range will be quite different than of the Heo
(Molinya) orbit. Africa will never be in range of Alaska on
Geostationary sats, unless satellite-to-satellite linking is
incorporated. We have already heard that this is not being considered.
For this reason I hold on to hope that P3E and one Eagle gets into a
high inclined orbit. If not then you can always work me on
OSCAR-ZERO since the (Moon) orbit is inclined 26 degrees!
Here is another fact to consider: ISS only reaches 11-12 degrees
elevation above our southern horizon. The orbit of ISS is inclined
51 degrees above the equator. Of course partly this is because it is
only 200 miles above earth. 23,500 miles is a bit more. The Moon at
250, 000 miles is even more.
How about earth-bound sat-gates to relay between Geo's?
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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