User Manual

VoiceXtender Modem Installer’s Guide
Installation and Setup
3-12 Rev. A - 8/97
Procedures for Fine Tuning the Antenna Alignment
The second step in the antenna alignment process is to fine tune the antenna to
ensure that the link is operating at the center of the main lobe. To fine tune the
antenna alignment, systematically adjust the transmit power by using the
following steps:
1. Set the master modem Transmit Level to 1 milliwatt.
The link will go down, and the SYNC indicator will go out. The slave
modem should still be at full power.
2. Increment the Transmit Level on the master modem, then slowly rotate the
antenna to attempt to illuminate the SYNC indicator on the slave.
Continue to cycle through the Transmit Levels and rotate the antenna at
each cycle until the SYNC indicator is illuminated.
When the SYNC indicator is illuminated, it indicates that the antenna is
correctly aligned on the main lobe.
3. Once the SYNC indicator is illuminated, note the Transmit Level, and
repeat steps 1 and 2 on the other modem.
4. Once both antennas have been finely tuned, the effective fade margin can be
calculated using the ratio of full power to the minimum power necessary to
illuminate the SYNC indicator.