Cross Polarization; Overview - iDirect evolution x1 Installation Manual

14 Cross Polarization

This chapter describes how to minimize return link cross-pol energy under the guidance of the
satellite access control center. This section includes instructions for both the iSite client and
the Web iSite interface.
This chapter includes the following sections:
• "Overview" on page 79
• "Satellite Access" on page 81
• "Performing Cross-Pol Adjustment" on page 82
• "After Securing the Antenna" on page 83

14.1 Overview

Cross-pol isolation is measured over-the-air by the satellite access control center. Be
prepared to contact the Network Operator by telephone.
Transmit cross-pol isolation is maximized in order to limit interference to users on the
opposite polarity of linearly-polarized satellite transponders. Typically, the spacecraft
operator requires a minimum of 30 dB of isolation. To measure this, the terminal must
transmit at a power level at least 30 dB above the noise floor of the transponder. The satellite
access control center measures and compares the received co-pol and cross-pol energy to
determine if the site meets polarity isolation standards.
VSAT terminals using circularly-polarized feed systems need not perform cross-pol tests.
To Prepare for Cross-Pol Adjustment:
1. Disconnect power from the Satellite Router.
2. Disconnect the receive IF cable from the Satellite Router.
3. Connect the transmit IF cable to the BUC Tx input.
4. Connect power to the Satellite Router.
5. For all Satellite Routers except the Evolution X1, X7, and e150, connect to the Satellite
Router using iSite. If commissioning an Evolution X1, X7, or e150, connect using a Web
browser.
6. Log in as Admin.
iDirect Satellite Router Installation and Commissioning Guide
iDX Release 3.3
79