Tektronix instruction manual 1705A Spectrum Monitor

Operating Instructions

Table 2- 3: Azimuth / Elevation Table for 21 CONUS Cities (Cont.)

Salt Lake 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˚
Washington DC	186˚	45˚	221˚	36˚	216˚	38˚

5.If the antenna is pointed close to a satellite, one or both polarizations of the full satellite will appear on the screen because the 1705A Spectrum Monitor is a much more sensitive indicator than a receiver and picture monitor.

Initially, there is no need to be concerned with antenna polarization or which satellite channels may be active.

6.If no satellite signal is observed, or the incorrect satellite is identified, sweep the antenna azimuth carefully around the expected satellite direction. If no satellite is found, return the azimuth to the expected direction and increase (or decrease) the elevation by about one degree and resweep the azimuth.

7.When a satellite signal has been observed on the 1705A display, it may be identified by the nature of the signals on the satellite. For example, wide bandwidth NBC television signals with multiple audio and data carriers on many transponders will identify Satcom K-2. Other satellites will have similar identifying characteristics. If the incorrect satellite has been selected, repoint the antenna to locate the desired satellite. Once any satellite is found and identified, a reference point is established and nearby satellites may be located by moving the antenna carefully in the proper direction.

8.Optimize the antenna by carefully adjusting azimuth and elevation while observing the signal strength on the 1705A Spectrum Monitor. At this time one or both satellite polarizations will be observed, but the received signal may not be a viewable picture for a picture monitor.

9.The polarization must be adjusted in a transmit/receive system by rotating the antenna feed to 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 will put the transmit signal on the wrong satellite transponder and create interfer- ence with another user. Furthur access to the satellite may be denied!

As the antenna feed is rotated, observe that there will be a sharp null of signals on one polarization or the other. Rotate the feed carefully to null the signals of the polarization that will not be used. Most news vehicle feed

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