Operation
RFI-148 250W VHF Paging Transmitter User Manual
Page 20 of 43
2-level FSK protocol data may optionally be clocked into the paging transmitter using the external data
clock or may run asynchronously. 4-level FSK protocols must use the external data clock.
Once the desired paging protocol, deviation and carrier offset settings have been selected, the
Save
Protocols
routine must be executed to apply the selected settings.
4.5 Fan Control
The transmitter has two fans for cooling; the front fan is an intake and the rear fan is the exhaust.
4.5.1 Current Fan Speed
The current fan speed displays the target fan speed by the fan controller as a percentage of total possible fan
speed. This value is set by the paging transmitter and depends on the fan control type, current temperature,
whether fan override is enabled or a fan test is in progress.
4.5.2 Control Types
The fans have two control types:
On/off:
The fans will turn on and off at a specified temperature. The fans turn on at the speed
specified by the fan speed setting parameter.
Linear scaling:
The fans will increase in speed as the transmitter heats up. The fan turn on and fan
turn off temperatures determine the how quickly the fans respond to increases in temperature. Once
the temperature exceeds the fan turn on temperature, the fans will then be set to full speed.
The fan control types act from a configurable temperature sensor. By default the fan controller will use the
highest temperature of all the temperature sensors.
4.5.3 Fan Override
There is a fan override feature available to force the fans to turn on at full speed. When fan override is
enabled the fans will ramp up to full speed and ignore the configured control type. Otherwise, the fans turn
off and on as specified by the control type.
4.5.4 Self-Test
The fan controller has a self-test feature which causes the fans to run at full speed for a minute so fan
operation can be verified. The self-test feature runs once every 24 hours by default.
