Tektronix 1705A - Manual (Page 32)

Introduction
1705A Spectrum Monitor 1- 13
Zeroing in on a Satellite
In almost all cases a set procedure for Locating, Identifying, Finding (transpond-
ers), and Optimizing will be followed. The 1705A Spectrum Monitor is a tool
that greatly simplifies the individual steps so the correct satellite transponder can
be accessed in the minimum time.
In most cases the elevation (angle above the horizon) and the true azimuth
(direction east or west to the satellite) of the antenna will be the same as it was
for the previous access of the same satellite. This angle can be found in one of
two ways, calculation or approximation from previous accesses; however, no
matter how the satellite is located the signal path will need to be optimized. In
most cases the approximate location of the satellite is known from previous
transactions and only identification of transponders and signal strength remain to
be dealt with.
Each of the satellites has one or more singular characteristics. In many cases the
singular characteristics can be easily identified on the spectrum monitor, which
can save valuable setup time. These characteristics can take the form of
telemetry beacons, transponder polarization schemes, or blocks of non-video
signals that stand out. And in a few cases, the easiest method of identification
may be the fact that the satellite is near another satellite that is readily identifi-
able.
Telemetry Beacons. Satellites have special tracking or telemetry beacons that
are easily recognizable on the spectrum monitor. Not only do these assist in
identifying the satellite, but they provide an accurate way to set the frequency
offset to correspond with actual satellite frequencies. Figure 1-6 shows a typical
Ku--Band satellite telemetry beacon. Note that the 1705A readout frequency can
be offset to read the down link frequency in GHz. Similar beacons can be found
on some C--Band satellites also.
Locating the Satellite
Identifying the Satellite