Table 6-9. Pa Bias 3 Alignment Device Bias Current - Motorola ASTRO XTL 5000 Basic Service Manual

6-8
4. Add baseline current to device bias current to calculate target current.
VHF 50 W/25 W
VHF 100 W
UHF R1 40 W
UHF R1 100 W
UHF R2 45 W
700–800 MHz 35 W
5. Left-click the Bias Toggle button to apply bias to gate of device.
6. Adjust softpot value until target current is achieved within
7. Left-click the Bias Toggle button to remove bias from gate of device.
8. Left-click the Program All button to save tuned value.
9. Left-click Close button to close the screen and return to the Tuner Main Menu.
6.4.4 Reference Oscillator Alignment
Radios are shipped from the factory with a worst-case frequency error of ±200 Hz for the VHF
frequency band, ±300 Hz for the UHF Range 1 and UHF Range 2 frequency bands and ±600 Hz for
the 700–800 MHz bands. These specifications are tighter than the more stringent FCC requirements
of ±2.5 ppm for the VHF, ±2.0 ppm for the UHF bands and ±1.5 ppm for the 700–800 MHz bands.
For radios that have been in storage for over six months from the factory ship date, the reference
oscillator should be checked when the radio is initially deployed to the field. It is strongly
recommended that the reference oscillator be checked every time the radio is serviced or at least
once a year, whichever comes first.
The crystal contained in the reference oscillator naturally drifts over time due to its aging
characteristic. Periodic (annual) adjustment of the reference oscillator is important for proper radio
operation.
Improper adjustment can result in both poor performance and interference with other users operating
on adjacent channels.
This test can be done with either the R-2670 Communication Analyzer or the Agilent 8901
Modulation Analyzer.
• Initial setup using the R-2670 Communication Analyzer:
- RF Control: MONITOR
- B/W: WB
- Freq: RSS frequency under test
- Attenuation: 20 dB
- Mon RF in: RF I/O
- Meter: RF Display
- Mode: STD
- Input Level: uV or W
October 30, 2006

Table 6-9. PA Bias 3 Alignment Device Bias Current

Band/Power Level
Radio Alignment Procedures: Transmitter Alignments
Device Bias Current (mA)
NA
150
30
150
30
100
±
10%
6871769L01-A