RC3000 Antenna Controller

Chapter 3

Detailed Operation

SCAN_TH:

SCAN THRESHOLD <0-999>

This threshold item defines what the minimum signal strength indication is required for the scan

procedure to recognize that a satellite is present.

The definition of this value is different depending on whether the L-Band power detector (RF) or one of the two signal strength (SS1 or SS2) channels is used for the autopeak signal source.

When using SS1 or SS2 as the autopeak signal source, the threshold value refers to the absolute value above which the scan procedure should recognize that a satellite is present. Per the signal strength adjustment calibration procedure (2.4.3.2), SS1 or SS2 channels should be tuned such that a value of approximately 50 is displayed when the antenna is completely off of a satellite (open sky) and a value of approximately 650 is displayed when the antenna is peaked up on a satellite. When using SS1 or SS2, a threshold value of 200 would typically be appropriate.

When using the RF (L-Band power) as the autopeak signal source, the threshold value refers to the amount of displayed value above the average noise floor reading that indicates the antenna is passing across a satellite. Note that the RF input is a logarithmic indication of total power across the L-Band (950-2150 MHz) range. Typically a value of 400 will be displayed when looking at the open sky. Also typically a value of 700 may be displayed when the antenna is looking at satellite with multiple transponders active. These values will vary according to the amount of attenuation in the system, satellite power, etc. When using RF, a threshold value of 100 would typically be appropriate.

When using either type of input as the autopeak signal source, the characteristics of the displayed value should be observed as the scan procedure moves across a satellite. If the threshold value is too low, the scan procedure may incorrectly recognize a random spike in the noise floor as an indication of a satellite. Conversely, if the threshold value is too high, the scan procedure may not recognize the presence of a satellite.

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HP RC3000 manual Scanth Scan Threshold