X8200 Datasheet, PDF (18/19 Pages) rfsolutions.ltd – Synthesised Radio Modem

Synthesised Radio Modem
X8200
X8200HP
Channel. Again observe the RSSI reading and make a note of any activity. Repeat this for
all the RF Channels.
The radio range can be tested by erecting a radio modem, Antenna and PC at the proposed
base station site. Select the Key Transmitter option.
Use a second radio modem, antenna at the distant site. If the Rx LED is lit then there is a
good propagation path. In addition the RSSI option can be selected for a more accurate
reading of the signal strength.
The propagation path can be tested by using the Access Remote Modem option. The RSSI
value from each of the distant modems will be measured, radioed back and displayed
Radio Propagation
When installing a X8200 Radio Modem there are a number of factors that should be
considered as they will affect the performance of the radio link. These are:
Transmitter power output.
Sensitivity of the receiver.
Height of transmitter and receiver antenna.
Length and type of the coaxial feeder cables to the antenna. These should be low loss RU67
type and kept as short as possible. As a rule of thumb the RF power is halved every 10m of
antenna feeder. It is better to keep the signal wire long and the antenna feeder short.
Type of Antenna used.
Surrounding Topography.
Interference for other networks operating on the same frequency.
The Weather.
7 Trouble shooting
No Data Transmission
Check that TD and RD are connected to the 9 way D Connector correctly. This can be
checked by using a voltmeter:
a)
Connect the Host to the Modem.
b)
With no signal present, measure the voltage between:
0V (Pin 5) and TD (Pin 3)
0V (Pin 5) and RD (Pin 2)
c)
Both should be between -5V to -15V.
If only one is at a negative voltage then the RD and TD connections are reversed.
No Data Reception
If the RX LED on the receiver is not lighting at the same time as the TX LED on the
transmitter then check the RF frequency is the same on both modems.
If the RX LED is lit when no data is being transmitted then there might be another user on the
channel. Select an RF channel were the RX LED is not lit.
If RX LED is flickering on all RF channels then look for a source of local interference such as
a switch mode power supply or a computer in close proximity.
DS8200-2 April ’07
©2007 RF Solutions Ltd, www.rfsolutions.co.uk
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