Many satellites are hybrids, meaning they have both C and Ku band transponders. In the main Satellite menu, these C and Ku bands will have different two-character codes. For instance, Telstar 4 is a hybrid. Its C-band code is T4, but its normal Ku-band code is W4.
Why? The Chaparral receiver thinks that each band (C and Ku) on each satellite is a separate satellite with its own unique two-letter code. When you switch from T4 to W4, it engages a whole different set of electronics. This is like switching a radio from AM to FM; your dial may be in the same position, but you're listening to a different part of the radio spectrum.
In our example, since T4 is used for the Telstar 4's C-band transponders, the receiver cannot use T4 again for any satellite in memory, including the Ku-band of that same satellite. An operator adding any new satellite must choose a letter and number which are not currently in use. Think about this: the Telstar series has five active satellites (all starting in "T"), and there are only 10 numerals available, so if the operator is determined to give the Ku-side of T4 a T-prefix, the only available combinations are T6, T7, T8, T9 or T0 (T-zero). (For more about the codes, see What are the Correct Two-Letter Abbreviations for Satellites? )
To carry the example further, we've noted that Chaparral currently uses W4 to designate the Ku-side of T4. However, the "W" prefix is also used for the C-band side of GE satellites, and GE-satellites 1, 2 and 3 currently exist. If another GE-satellite goes up, since W4 is already in use Chaparral will have to find another prefix for the GE-series or will have to assign a new code to Telstar 4-Ku. Clearly, this situation can be confusing! It seems that since most consumers use the C-band satellites, Chaparral uses the most "intuitive" letters for C-band and less intuitive letters for Ku satellites, which are used more by industry.
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Copyright 1997, Dr. Albert E. Powell, Jr.
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