TECHNISONIC INDUSTRIES LIMITED
www.til.ca
TAF-550 Installation & Operating Instructions
TiL 96RE187 Rev D
2-4
2.2.3
Transmitter Power Adjustments
The transmitter power is adjusted to a maximum of 10 watts in high power mode and 1 watt in low
power mode over the transceiver operating bandwidth at the factory. If transmitter RF power re-
adjustment is required, perform as follows:
(1)
Remove bottom cover as described in the previous paragraph (2.2.2). Access to the two
adjustment potentiometers on the Microprocessor Control Unit (MCU) PCB Module is
provided by two access holes located at the back of the chassis tray.
(2)
Connect an RF through-line wattmeter to the antenna connector. Set the operating
frequency to 156.000 MHz and key the transmitter.
(3)
In low power mode, set the low power adjustment potentiometer R24 to produce 1.0 watt
of RF output power (See Figure 2.2).
(4)
In high power mode, set high power adjustment potentiometer R23 to produce 9.5 watts
of RF output power.
(5)
Verify that the RF output power is between 9 and 10 watts on 138.000 MHz, 162.000
MHz and 174.000 MHz.
(6)
Replace bottom cover as described in the previous paragraph (2.2.2).
2.2.4
Transmitter Microphone Level Adjustment
(1)
Set the transceiver operating frequency to 156.000 MHz and connect an appropriate test
receiver to the RF output connector. Ensure that the output of the transceiver is
terminated into a proper dummy load.
(2)
Key the transmitter and input a -10 dBm (0.25 VRMS), 1 KHz audio signal into the
microphone input.
(3)
Adjust the microphone level potentiometer (R8 on MCU module) through the access hole
located on the right side of the chassis (see Figure 3-4) to produce a 3.5 KHz deviation.
(4)
Verify that the deviation is at least 3 KHz on the following frequencies: 138.000 MHz,
162.000 MHz and 174.000 MHz.
