7-12 Adjustments 8525B/8528 Technical Service Manual
Issue 6 Publication No: 15-02036
7.3.14 Output Power
1. Ensure the dual coax socket is connected to the PA and filter PCB.
2. Connect an RMS or PEP power meter with dummy load to the antenna
socket.
3. Connect a CRO via a 47kΩ resistor to the antenna socket.
4. Connect the audio output of the two-tone source to the test unit (AF in).
Ensure the microphone amplifier is into compression.
5. Select the lowest frequency channel on the transceiver and operate the
microphone PTT switch.
6. Select a value for the SET PWR resistor (R10) to set the two-tone
output to:
• for type 8525B/8528—100W PEP (i.e. 200Vpp into 50Ω)
• for type 8528S—125W PEP (i.e. 224Vpp into 50Ω)
7. Check the IMD (Intermodulation Distortion) over the band 2MHz to
24MHz. The power output may be reduced if necessary to give −26dB
IMD on the worst channel.
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