Isolating the transmit signal – Hughes DIRECWAY AN4-074-DF User Manual

Page 66

Chapter 5 • Pointing the antenna

1035567-0001 Revision A

Isolating the transmit
signal

To prevent signal cross talk, you use a procedure known as
Automated Cross Polarization (ACP) to isolate the transmit signal
from the receive signal. ACP is included in the installation
software.

The ACP software operates in two different modes—manual or
automatic fine pointing. The automatic mode takes a snapshot of
the cross polarization isolation measurement, while the manual
mode gives real-time feedback of cross polarization isolation
measurement while adjusting the antenna. Passing the automatic
test enables the transmitter. Once the transmitter is enabled, the
site is ready to be registered.

The ACP method consists of using the manual and/or automatic
fine pointing tests and adjusting the antenna by small increments
(if necessary) until it passes the automatic ACP test.

Follow the general instructions below for the ACP tests. Use the
installation software screens to initiate tests and see the test
results.

First run an automatic ACP test:

1. Before running ACP tests, lock down all antenna adjustment

nuts and bolts.

2. Initiate an automatic ACP test.

If the antenna passes this test, it is pointed and ready to be
registered.

The following test is necessary only if the antenna fails the
automatic ACP test:

1. Loosen the four polarization nuts one-quarter of a turn—just

enough so you can adjust the polarization.

2. Using the software screen, initiate a manual ACP test.
3. When the test starts, make small, 1

or less changes in

polarization while observing the transmitter isolation.

4. Peak the polarization to the highest possible transmitter

isolation.

5. Tighten the four polarization nuts.

6. If the antenna passes the manual test, stop the test and run the

automatic ACP test again.
If the antenna passes the automatic test, it is pointed and
ready to be registered.

Note:

When you adjust any one of the axes (polarization,

elevation, or azimuth) you may also have to adjust one or both
of the other axes.