Introduction
1705A Spectrum Monitor 1-15
11.729GHz 11.788GHz 11.847GHz 11.906GHz 11.965GHz 12.024GHz 12.083GHz 12.142GHz
11.7585GHz 11.8175GHz 11.8765GHz 11.9355GHz 11.9945GHz 12.0535GHz 12.1125GHz 12.1715GHz
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
HORIZONTAL
POLARIZATION
VERTICAL
POLARIZATION
DOWNLINK
FREQUENCY
TRANSPONDER
NUMBER
FREQUENCYAND NUMBER
TRANSPONDER
Figure1 -7: Transponderassignments f or a typical Ku-Band, 16-transponder satellite that employs alt ernate
polarization(Not allKu-Band satellit es conform to these frequencies and/or this polarization scheme)
Once the satellitehas been found it will be necessary to find the propertrans-
ponder and determineif it is available. With the 1705A frequency readout offset
correctlyset up, it is possible to directly zero in on the correct transponder.
Figure 1-8 is a computer simulation of the 1705A Spectrum Monitor display in
FULL SPAN/DIVISION. Each division corresponds to 100 MHz. If the
satellite previouslydiscussed is being looked at and the brightup is on the first
marker,then the first signal is transponder number 1 and the antenna feed hornis
horizontally polarized. F urther,it is possible to determine that transponders 5, 7,
9, 13, and 15 are currentlyin use. Rotating the feedhorn polarity 90˚would
bring up a display ofthe vertically polarized transponder down links.
Once the correctsatellite has been identified, minor adjustment to the antenna
position will optimize the link. The antenna azimuth and elevationcan be fine
tuned for maximumsignal strength and the opposite polarization carefully nulled
while observing the spectrummonitor crt screen.
FindingThe C orrectTransponderOptimize Signal Strength