Sea Tel 4009-9 BROADBAND-AT-SEA, Руководство по установке

Страница: 47 / 153

Setup – Tracking Receiver – VSAT 4009-9 Installation Manual
6-1
6. Setup – Tracking Receiver – VSAT
6.1. Determining the IF Tracking Frequency (MHz)
The IF Tracking frequency parameter is a value entered into the ACU’s MHZ Sub-Menu. The value itself may be
provided by your air-time provider and the MHz value will be entered directly in this sub-menu.
Or, the RF downlink frequency of a specific carrier on the desired satellite can be obtained from a satellite website
and calculated by using the formula RF- LO = IF. When you take the Satellite Transponder Downlink RF value and
subtract the LNB’s Local Oscillator (LO) Value, the resultant value will equal the Intermediate Frequency (IF). It is
this IF value that will be entered into the ACU for tracking purposes.
Example assuming an LNB LO value of 11.25GHz: 12268.0 MHz – 11250.0 MHz = 1018.0 MHz IF
Identifying the Downlink RF using SatcoDX
Identifying the Downlink RF using Capture from Lyngsat.com
6.2. KHz
The KHz rate entered into the ACU is an absolute value that is entered directly in this sub-menu window. This
value may have been provided by your air-time provider or have been calculated.
In the example above, 1018.0 MHz was calculated (1018 MHz 000 KHz) therefore, the KHz entry would be 000. If
the provided/calculated value had been 1018.250, 1018 would have been entered in the MHz window and 250
would be entered in the KHz window.
6.3. FEC
6.3.1. L-Band SCPC Receiver
The Forward Error Correction rate entered into the ACU should always be set to SCPC with an L-Band
SCPC receiver card installed in the ACU.