DAVIS CELLULAR TELEPHONE ANTENNA KIT User Manual download pdf (Page 6)

Range

Table 2 gives estimated ranges for combinations of Davis-supplied antennas with line-of-sight paths between

them. Range estimates for other antenna gains may be found by using Figure 4.

ESTIMATED RANGE

Omni-to-Omni

mi. km

Omni-to-Yagi

mi. km

Yagi-to-Yagi

mi. km

YDI RM910 8.5 dB Yagi 0.9 1,4 1.6 2,6 3.0 4,8

YDI RM910 12 dB Yagi 2.3 3,7 7.0 11,2

Neulink 9600 4.0 6,5 10.0 16,0 25.0 40,0

Table 2. Transmission Distance, Line-Of-Sight, vs. Antenna Type

Power

AC Power

If AC “mains” power is available at the field and base stations, the radios may be on continuously and the

WeatherLink operated in its normal modes.

Solar Power

If the field station is operating on solar/battery power, it is necessary to switch power to the radio so it is off

most of the time in order to conserve the charge drained from the battery. The radio’s power is switched on by

the Timer or the Alarm Output Module for brief pre-determined intervals to allow communication.

The AOM enables the modem at 5 minutes past each even-numbered hour (according to the time clock in the

Console) and keeps it enabled for four minutes. When a communication is received, the modem remains

enabled during the data transfer and for two minutes thereafter; no communication is interrupted.

The Timer can be set to any intervals the user selects. Any radio communication in progress when the Timer

switches OFF will be interrupted. (Exception: a cell-phone call will not be interrupted.)

The “Charge Budget,” discussed below, is one means of determining the amount of time that the radio may be

on each day.

Charge Budget

When using the radio in a solar/battery-powered station, one must limit the power drawn by the radio. This

means limiting the time that the radio is ON, enabled to receive messages, and -- in most cases -- limiting

even more severely the duration of transmissions.

WeatherLink Radio Communications 6

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DAVIS CELLULAR TELEPHONE ANTENNA KIT User Manual Page 6