MM-015371-001, Rev. C
75
15.5 TRANSMITTING INTO THE MOBILE ANTENNA
1.
Connect the antenna cable from the vehicle-mounted antenna to the wattmeter as shown in Figure
15-2.
2.
If not already, turn the radio on and set it to the required operating mode (based upon available radio
programming and test equipment). Refer to Section 15.1 as necessary.
3.
Set the radio to a test talk group or conventional channel, if available.
It is recommended that a test talk group/channel be allocated for this testing.
Otherwise, interference with other radio users in the system may occur.
Also, during
transmissions, always observe the RF exposure-related safety information
presented in Section 1.2 (begins on page 6).
4.
Position the wattmeter’s slug to measure forward RF output power. Rotate it if necessary. The arrow
on the face of the slug must point away from the radio and towards the antenna for forward power
measurements.
5.
For conventional mode transmissions
, set the wattmeter to measure average RF power.
For OpenSky mode transmissions
, set the wattmeter to measure peak RF power.
6.
Key the radio’s transmitter via the microphone’s PTT button.
7.
Verify the measured forward RF output power into the antenna is within 20% of the maximum
transmit output power (in watts) programming performed per Section 15.3.
Transmit only for as long as needed to take the measurement, then immediately
disable the transmission.
8.
If the wattmeter reading is within the range,
record the value in the appropriate space on the data
collection form near the end of this manual.
If the wattmeter reading is outside the range,
verify the radio’s power supply voltage (i.e., battery
voltage) is within the specified range, recheck all connections, and measure the forward power again.
If these checks/corrections fail to produce a reading within the range, check all cabling and
connections and repeat the testing procedure to this point. In the event the wattmeter reading still falls
outside the range, replace the antenna, make sure all connections are seated firmly, and repeat the
testing procedure. If problems persist, contact the Technical Assistance Center (see page 19).
9.
Position the wattmeter’s slug to measure reverse (reflected) RF power from the antenna. The arrow
on the face of the slug must point away from the antenna and to the radio to measure reverse power.
10.
Key the radio’s transmitter via the microphone’s PTT button.
11.
Verify the wattmeter indicates
2 watts or less.
Transmit only for as long as needed to take the measurement, then immediately disable
the transmission.
