Agc Above Threshold For Noise Input Test; Agc Input Below Threshold For Active Satellite Transponder Test; Agc Input Saturated For Active Satellite Transponder Test - RESEARCH CONCEPTS RC2000A DUAL AXIS Instructions Manual

Threshold. The controller will attempt to peakup the antenna but a true peak cannot be found. In the
process, the antenna may move away from the actual position of the satellite. Note that the noise
output of a satellite recevier will increase when the antenna is aligned with the sun. This will occur
when the sun lies in the earth's equatorial plane – this occurs in mid March and mid September. Note
that if the controller is peaking the antenna on the sun, in many cases a Peak Limit Error will occur –
see chapter 3 for more information.
ii) The antenna is aligned with a satellite, the receiver is tuned to an active transponder, but the AGC
input is below the appropriate threshold. In this case peaking will not occur because the AGC is below
threshold.
iii) The antenna is aligned with a satellite, the receiver is tuned to an active transponder, but the AGC
input channel is saturated (AGC reading near 1023). In this case peaking will occur but a true peak will
not be found because moving the antenna closer to or farther away from the satellite does not change
the signal strength as displayed by the controller.

1.2.1 AGC Above Threshold for Noise Input Test

To insure that (i) is unlikely to occur tune the antenna away from any satellite. Tune the receiver over
all transponders on any frequency bands of interest. Watch the displayed signal strength to insure that
it is never above the appropriate Threshold. If the antenna is equipped with a four port feed that can
receive both C and Ku band, horizontal and vertical polarizations simultaneously (like the Seavey
ESA124D), make sure that the test is performed with both bands and both polarizations. Additionally, if
both controller AGC channels are in use, perform the test for both receivers (the Scroll Up/Down keys
can be used to select the AGC channel of interest from MANUAL mode).

1.2.2 AGC Input Below Threshold for Active Satellite Transponder Test

Perform the following procedure to insure that type (ii) problems do not occur.
Align the antenna with a weak satellite.
Tune the receiver over all transponders on any frequency bands of interest.
Insure that for all active transponders the displayed signal strength is above Threshold.
Note that for four port feeds, perform the test for both bands and both polarizations. For installations
that utilize both controller AGC input channels, perform the test on both receivers. From MANUAL
mode, the Scroll Up/Down keys can be used to select the AGC input which is displayed. As an
alternative to aligning the antenna with a weak satellite, a strong satellite can be employed if the
antenna is jogged off of the satellite to reduce the received signal strength.

1.2.3 AGC Input Saturated for Active Satellite Transponder Test

Perform the following procedure to insure that type (iii) problems do not occur.
Align the antenna with a strong satellite.
Tune the receiver over all transponders on any frequency bands of interest.
Insure that for all active transponders the displayed signal strength is well below saturation. A
conservative approach is to treat any signal with a displayed signal strength above 900 as saturation.
Note that for four port feeds, perform the test for both bands and both polarizations. For installations
that utilize both controller AGC input channels, perform the test on both receivers. From MANUAL
mode, the Scroll Up/Down keys can be used to select the AGC input which is displayed.
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