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40 What Is An Inclined Orbit Satellite And How Can I Receive Them?




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This article is from the Satellite TV FAQ, by Gary Bourgois flash@lopez.marquette.mi.us with numerous contributions by others.

40 What Is An Inclined Orbit Satellite And How Can I Receive Them?

Inclined orbit birds are satellites that "wobble" north and south of the
vary in the vertical plane, as explained in the previous paragraph. At
the end of a satellite's life, when station keeping fuel is running low
if a replacement satellite is not ready, there is the option to "go
inclined". One method used is called the "Comsat Maneuver", which puts
the bird into an elongated figure 8 pattern. On C band this method can
get 6 months or more of life out of a near dead satellite (Usually the
electronics are fine, it is just the low amount of Hydrazine fuel that
marks the EOL or End Of Life of a satellite. On C band a slightly
inclined satellite will appear to have a weaker signal during parts of the
day when it is off axis. Many of us remember that this was done with the
old Telstar 301, causing some of the Wild and Network feeds to be less than
perfect. However, it is better than no satellite at all, which is the
case when a launched bird BLOWS UP like Telstar 402 did in late 1994, meaning
that 302 will go inclined while waiting for T-402R. In addition to these
situations, there are birds that are kept in inclined orbits for YEARS.
Several Intelsats are this way, as are a couple of SBS birds, such as
SBS3. ON KU band, because of narrower beamwidth, an inclined bird can
only be viewed during an hour or so a day on a standard satellite system,
when its wobble places it directly over the equator. The Robert Smathers
SSSSC Chart lists the times of day you can pick up these inclined birds.
Some, like SBS3 have a continuous ID slate so you can find them.
Professional Downlinkers often have DUAL AXIS tracking systems which allow
for adjustment in the vertical as well as horizontal plane. In 1995, NBC
will move its feeds off K2 and onto an inclined SBS bird. All NBC affiliates
will be outfitted with costly auto tracking systems. The good news is that
it is now possible for the HOME BACKYARD TVRO OWNER to install his own
system to track these inclined orbit birds. The key component of this
setup is a "vertical kit" which consists of a heavy steel "hinge" which
will allow your dish to move up and down. The cost for this kit is around
$70, and if you are a bit of a tinkerer, it is well worth the money. To this
kit, you simply add a positioner arm (you can do like I did and scrounge one
for very little money) and you will need a means of providing the 24 volt
DC current with switchable polarity. This can be accomplished by using
an old manual type dish positioner to control the vertical tracking. These
can be had free or very cheap. Such a system is NOT automatic, you need
to use your eyeballs and your IRD's signal readout to peak the signal and
you need to adjust the tracking every 10 minutes or so. If you are chasing
newsfeeds, this won't be too much bother. If you really get into tracking
inclined birds, there are computerized tracking systems, and even a few
IRD's that have the ability to track them automatically. It depends on
your own tastes, desires, and level of technical expertise. The vertical
kit I purchased was from Global Communications (See Dealer list at end of
this article) Since he is a TVRO dish design engineer, he can quickly
determine if your system will adapt to this type of system. Hint: if you
have an AJAK H/H drive, the answer is YES! During the Olympics it was fun
to be able to watch the feeds LIVE and not have to wait for the USA delay
broadcasts. Many of these feeds were on an inclined Intelsat. Besides
NBC, activity on inclined birds is fairly sparse, mostly special feeds.
Thus the option of being able to track these satellites is not for everyone
but the option is certainly there for folks who do.

 

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