Installation and Initialization
QB.11-R Installation and Management
Installation Procedure
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Step 12: Align the Antenna
Antenna alignment is the process of physically aligning the antenna of the radio receiver and transmitter to have the best
possible link established between them. The antenna alignment process is usually performed during installation and after
major repairs.
If you are installing external antennas, consult the documentation that accompanies the antenna for installation
instructions. Note that you must weatherproof the antenna connectors as described in
The unit has an audible antenna alignment tool that can be activated by plugging in the supplied serial dongle (supplied
with the BSU) or by issuing the CLI command for antenna alignment. The CLI command causes both audible and
numerical feedback as the CLI shows the running Signal-to-Noise Ratio (SNR) values twice a second.
The output from the beeper for antenna alignment consists of short beeps with a variable interval. The interval changes
with the SNR level to assist in correctly aligning the antenna. An increase in signal level is indicated by a shorter interval
between beeps; a reduction in signal level results in beeps longer apart.
To allow for precise antenna alignment, small changes in SNR result in large changes in the beep period. The alignment
process averages the SNR, which is represented by an average length beep. When a higher SNR is received, the beep
period is made shorter, dependent upon the difference to the average. A lower SNR results in a longer period between
beeps.
The first five steps around the average are represented by a large change and all following steps are a small change.
This acts as if a magnifying glass is centered around the average SNR and the values next to the average are
significantly different.
When the antenna is aimed, the beep intuitively represents whether the SNR is rising or falling: the higher the SNR rises,
the shorter the period the beep is heard and the higher the frequency of the beep.
After the position of the antenna has been changed, SNR averaging settles at the new value and the beeping returns to
the average length so the antenna can again be aimed for rising SNR.
Aiming is complete if moving in any direction results in a falling SNR value (which can be heard as longer periods
between beeps).
NOTES:
•
Antenna alignment for the Base Station is useful only for a point-to-point link.
•
The range of the average SNR has been limited to values from 5 to 43; therefore, anything over 43 always
results in a short period between beeps and values below 5 always have a long period.
