[amsat-bb] Link Budget
Edward R Cole
kl7uw at acsalaska.net
Sat Nov 7 21:39:41 UTC 2015
I don't recall exactly but there is geostationary and there geocentric orbits.
The orbit that is not zero inclination will trace a figure 8 in the
sky but its not a large deviation in position. If 5GHz is being
considered for the link, antenna gain may be fairly high but will
they have a beamwidth narrower than the angular deviation that the
figure 8 makes? How big a dish? 2-foot? 3-foot? Get out your
sliderules and calculate the beamwidth (no I will not do it for you).
I think the inclination in geotationary is not very high (maybe a few
degrees; i.e. <10). The apparent motion would be diurnal so nothing
rapid. One could probably use a manual setting for a few hours.
Just a guesstimate.
73, Ed - KL7UW
From: Burns Fisher <burns at fisher.cc>
To: Joe <nss at mwt.net>
Cc: AMSAT BB <amsat-bb at amsat.org>
Subject: Re: [amsat-bb] Link Budget
<CABX7KxVtXXFHvm_3_BLd4SKyTDRSpOdYwsA+x+kXJrTNHG0Eew at mail.gmail.com>
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While it appears that you are right about the link budget, one of you
arguments holds only *some* water, and that is tracking.
GeoSTATIONARY birds would require to tracking, but there are
geosynchronous orbits (i.e. 24 hours, but not necessarily 0
inclination and 0 eccentricity) which would move north/south or
east/west in the sky over the course of a day.
And regarding the moon: Another argument against it is that it is
darned hard to land on the moon. Lots more deltaV required.
73, Ed - KL7UW
"Kits made by KL7UW"
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