Technical Manual

Table Of Contents
120 20170-201 Paragon
PD
Technical Manual
38
6.2.4 Power Amplifier Module (T889)
1. Re-install the exciter module into the Paragon rack frame
2. Connect the Exciter module to the Power Amplifier
3. Connect the Power Amplifier output to the IFR T/R connector or to a stand-alone BIRD
style power meter, terminated with a 150W dummy load.
6.2.4.1 Power Amplifier Power Out
1. Set RV63 (Power adjustment, access on the front panel) fully clockwise.
2. Key the transmitter from the exciter Carrier button. The power output should exceed
90W.
3. Adjust RV69 (Driver power, access from the left end side) until the output power drops
to 90W.
4. Adjust RV63 (Power) to reduce power output to its nominal value (70W) or lower as re-
quired.
5. Cable loss should be included in the reading.
6.2.4.2 Forward Power Alarm Level
1. Power up the T889 and adjust RV63 (Power) so that the output power is at the alarm
level required, usually 20% lower than nominal value (e.g. 40W if the PA normally op-
erates at 50W).
2. Adjust RV48 (Forward power Alarm set) so that the forward power alarm LED lights.
3. Adjust RV63 (Power) for the normal operating power level.
6.2.4.3 Reverse Power Alarm Level (Optional)
1. Power up the T889 and adjust RV63 (Power) for the normal operating power level.
2. Place a known mismatch of the required value (e.g. 3:1 VSWR) and adjust RV52 (re-
verse power alarm set) so that the reverse power alarm LED lights.
Example: A VSWR of 3:1 can be simulated by connecting an undetermined 3 dB pad to
the PA output. This will result in a loss of 6 dB.