Xylem H-4400 - Manual (Page 5)

H-4400
RS-232 Data Radio 1-3
Configure the repeater station as follows:
1. Set the power control jumper of the repeater to “Always On”. This causes the radio to be
powered continuously.
2. Install a special loopback connector on the RS-232 connector of the radio.
3. Make certain your +12V power source can provide 60mA continuous, 200mA for short
bursts.
1.3 Connecting the Antenna
The H-4400 may be used with a 50-ohm, 900 Mhz antenna providing the effective radiated power
is 6dB or less. The antenna connector is a reverse type-TNC connector which is required to
meet FCC part 15.203 regulations. A simple vertical whip antenna will work up to 2 or 3 miles.
Longer distances require a directional antenna with gain. A 6dB or 9dB YAGI will work fine, do
not use a 12dB model. At 900 MHz, RG58 type coaxial antenna feed lines have excessive loss
(1.8dB/10 feet). Consider using newer low loss RF cable such as Times Microwave LMR-400 or
similar (0.8dB/10 feet). The LMR-400 requires special RG8 connectors.
The H-44000 is packaged in a weather tight enclosure and is best mounted as close to the antenna
as possible. The H-4400 has a ground lug which should be connected to a good earth ground
with a heavy copper wire. The ground helps provides lightning protection for the radio, your
sensors and the data logger.
The H-4400 radios all operate at the same frequency. If multiple data logger sites are deployed,
make certain the radios of each separate logging site cannot “hear” each other. The radios can be
ordered with alternate frequencies, please contact the factory for further information.
Words of caution:
• Even though the master H-4400 operates in a low power mode, the transmitter
requires 200mA for short bursts. Make certain your wiring and battery is capable of
supplying sufficient current.
• Keep the lead wires as short as possible.
• Use shielded cables in noisy environments.
• Connect the ground post to a good earth ground.