Operating Instructions
1705A Spectrum Monitor 2-19
Table2- 3: Azimuth / Elevation Tablef or 21 CONUS Cities ( Cont.)
SaltLake City 137˚34˚169˚42˚155˚39˚
San Francisco 125˚28˚154˚42˚140˚38˚
Seattle 131˚22˚158˚32˚146˚29˚
St. Louis 166˚44˚204˚42˚188˚45˚
WashingtonDC 186˚45˚221˚36˚216˚38˚
5. If the antennais pointed close to a satellite, one or both polarizationsof the
full satellitewill appear on the screen because the 1705A Spectrum Monitor
is a much more sensitive indicatorthan a receiver an d picture monitor.
Initially,there is no need to be concerned with antenna polarization or which
satellite channelsmay be active.
6. If no satellite signal is observed, or the incorrectsatellite is identified, sweep
the antennaazimuth carefully around the expected satellite direction. If no
satellite is found, returnthe azimuth to the expected direction and increase
(or decrease)the elevation by about one degree and resweep the azimuth.
7. When a satellitesignal has been observed on the 1705A display, it may be
identified by the natureof the signals on the satellite. For example, wide
bandwidth NBC television signals with multiple audioand data carriers on
many transponderswill identify Satcom K--2. Other satellites will have
similar identifying characteristics. If the incorrect satellite has been selected,
repoint the antennato locate the desiredsatellite. Once any satelliteis found
and identified, areference point is established and nearby satellites may be
located by moving theantenna carefully in the proper direction.
8. Optimize the antennaby carefully adjusting azimuth and elevation while
observing the signalstrength on the 1705A Spectrum Monitor. At this time
one or both satellite polarizationswill be observed, but the received s ignal
may not be a viewable picturefor a picture monitor.
9. The polarizationmust be adjusted in a transmit/receive system by rotating
the antenna feedto minimize the undesired, cross polarized signal.
WARNING.This adjustment requires a spectrum monitor and should not be
attempted using a receiver and picture monitor alone. Any mis-adjustment wil l
put the transmit signal on the wrong satellite transponder and createinterfer-
ence with another user. Furthur access to the satellite may be denied!
As the antenna feedis rotated, observethat there will be a sharp null of
signals on one polarizationor the other. Rotate the feed carefully to null the
signals of the polarizationthat will not be used. Most news vehicle feed