Installation | DART 300 Modem |
a RF engineer. However, if you do not have the option to do a test first, this analytical approach is your only option.
10.2. 3-Watt Class I Booster Operation
The DART 300 modem is capable of supporting the Sierra Wireless AirBooster 350 RF Amplifier. This device boosts the 600 mW (Class III) output of the modem to a maximum 3W (Class I) output.
The DART 300 modem can automatically detect the presence of the AirBooster 350 amplifier. Due to the hardware required to support this
CAUTION
In cases where the antenna output is to be connected to test equipment, DC blocks must be used on the antenna output to protect the test equipment and avoid false booster detection.
The amplifier is an “intelligent” booster in that it does not simply apply a fixed gain to a varying input RF level like a linear amplifier would. Instead, the AirBooster amplifier takes a constant RF level from the CDPD device and applies as much gain as the CDPD system allows at that moment.
In order to achieve this there is a control signal used between the modem and the AirBooster 350. This signaling is used to enable the RF amplifier and to control its output level. Without the control signal (such as plugging a
The DART 300 uses a control register at +WS214 (Booster Support) to enable or disable the use of the control signal. This register is enabled (set to 1) by default. If it is disabled and the AirBooster 350 is connected, the modem will suffer the same transmission impairment as any other
10.2.1.Connection
A custom connection cable (Male TNC to Male SMA) is used. Due to the variation in required cable lengths and connector types that may be needed between the booster and the host CDPD device, there is no host cable in the AirBooster 350 RF amplifier package. These cables are ordered separately from Sierra Wireless (part number 2000096).
The steps involved in the connection are:
1.Ensure both the modem and the amplifier are powered off.
2.Connect the TNC connector to the DART 300 antenna connector.
3.Thread the cable between the DART 300 and the AirBooster 350 amplifier.
4.Attach the SMA connector to the AirBooster 350 MODEM connector. Tighten firmly by hand; do not use tools.
5.Apply power to the AirBooster amplifier. The AirBooster power indicator will light.
6.Apply power to the DART 300. The AirBooster amplifier’s status indicator will light when the modem has detected the amplifier.
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