4RF Limited SRN0400025A ユーザーズマニュアル
208 | Managing the Radio
Aprisa SR User Manual
Antenna Alignment
A base station omni directional collinear antenna has a vertical polarization. The remote station yagi
antennas must also have vertical polarization.
antennas must also have vertical polarization.
Aligning the Antennas
Align the remote station yagi antennas by making small adjustments while monitoring the RSSI. The Aprisa
SR has a Test Mode which presents a real time visual display of the RSSI on the front panel LEDs. This can
be used to adjust the antenna for optimum signal strength (see ‘Test Mode’ on page 26).
SR has a Test Mode which presents a real time visual display of the RSSI on the front panel LEDs. This can
be used to adjust the antenna for optimum signal strength (see ‘Test Mode’ on page 26).
Note: Low gain antennas need less adjustment in elevation as they are simply aimed at the horizon. They
should always be panned horizontally to find the peak signal.
should always be panned horizontally to find the peak signal.
1. Press and hold the ENTER button on the radio LED panel until all the LEDs flash green (about 3 - 5
seconds).
Note: The time for the LEDs to display the RSSI result is variable, depending on the network traffic,
and can be up to 5 seconds. Small antenna adjustments should be made and then wait for the display
to refresh.
and can be up to 5 seconds. Small antenna adjustments should be made and then wait for the display
to refresh.
The RSSI poll refresh rate can be set with the SuperVisor command ‘Transmit Period’ (see
‘Maintenance > Test Mode’ on page 128).
‘Maintenance > Test Mode’ on page 128).
2. Move the antenna through a complete sweep horizontally (pan). Note down the RSSI reading for all the
peaks in RSSI that you discover in the pan.
3. Move the antenna to the position corresponding to the maximum RSSI value obtained during the pan.
Move the antenna horizontally slightly to each side of this maximum to find the two points where the
RSSI drops slightly.
RSSI drops slightly.
4. Move the antenna halfway between these two points and tighten the clamp.
5. If the antenna has an elevation adjustment, move the antenna through a complete sweep (tilt)
vertically. Note down the RSSI reading for all the peaks in RSSI that you discover in the tilt.
6. Move the antenna to the position corresponding to the maximum RSSI value obtained during the tilt.
Move the antenna slightly up and then down from the maximum to find the two points where the RSSI
drops slightly.
drops slightly.
7. Move the antenna halfway between these two points and tighten the clamp.
8. Recheck the pan (steps 2-4) and tighten all the clamps firmly.
9. To exit Test Mode, press and hold the ENTER button until all the LEDs flash red (about 3 – 5 seconds).