Campbell RF451, Instruction Manual

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RF451 Spread Spectrum Radio
11
This is useful when there are parallel repeaters in a network, and you want to
force communication through a particular repeater. When this setting is used,
the repeater will receive on the Frequency Key of the upstream master (or
repeater), and transmit on its Frequency Key setting (which typically is set to
a different value than the master’s).
The default setting of box, not checked (use master frequency), causes the
repeater to transmit on the master’s Frequency Key .
When this setting is not used, the Frequency Key setting should
match that of the master or of the repeater acting as the master for
that transceiver.
7.2.8 Transmit Power
This setting specifies the RF transmit power. Use a transmit power of 0 when
bench testing to reduce RF exposure.
The FCC specifies a maximum EIRP (Effective Isotropic Radiated Power) of
36 dBm.
EIRP = (Transmitter Power) + (Antenna Gain) - (Cable Losses) [all in dB or
dBm]
Radio installations should be performed by a professional. It is very important
that the transmit power level selected and the gain of the attached antenna do
not exceed the maximum allowed ERP permitted by local regulations.
Regulations vary by country and region. As the equipment owner, you are
responsible for making sure that your installation and maintenance of the radio
equipment ensure local regulations are met. For example, in much of the
United States, FCC part 15 rules limit the 900 MHz, ISM band transmission
from the RF451 to a maximum effective radiated power of +36 dBm.
The RF451 maximum power is 30.0 dBm; therefore, a 6 dB (or lower) gain
antenna can be used with any
Transmit Power
setting. If a higher gain antenna
is used, the cable loss will need to be determined, and the Transmit Power
adjusted so as not to exceed the FCC limit of +36 dBm.
Note that lower Transmit Power can be used (to conserve battery power) if
the required range allows it.
TABLE 7-1 shows the RF451 RF transmit power versus the setting.
NOTE