Preparing The Equipment For Uhf Alignment; Tuning The Uhf Preselector; Figure 60: Preselector Tuning - Uhf - Motorola ASTRO 25 GTR 8000 Manual

MN003286A01-E
Chapter 5: GTR 8000 Base Radio Optimization
5.9.2.2

Preparing the Equipment for UHF Alignment

Perform the following procedure to prepare the equipment for UHF alignment.
Procedure:
1 Ensure the base radio (with preselector assembly) is installed in a functional station cage
equipped with a power supply module.
2 Using the torque driver and deep well socket, loosen the three tension nuts on the adjustment
screws.
3 Detune the preselector by turning tuning screws 3 and 4 clockwise until they bottom out. Be
careful not to apply more than 3 in-lb of torque to prevent warping preselector cover and
housing.
4 See Figure 60: Preselector Tuning — UHF on page
5.9.2.3

Tuning The UHF Preselector

NOTICE: When tuning for peak or dip, turn the tuning screw 1/2 turn past the peak or dip to
verify that you have obtained a true peak or dip. After you have found true peak or dip, turn the
screw back to the location of the original peak or dip.
See the figure for the location of the tuning screws and cavity probe holes.
Figure 60: Preselector Tuning — UHF
Procedure:
1 Turn the power supply ON (to provide a 50 Ohm termination).
2 Adjust the signal generator to the frequency calculated in
Frequency For a Single Receive Frequency on page 163
Frequency for Multiple Receive Frequencies on page
3 Insert the tuning probe into cavity U2 and adjust tuning screw 2 for a PEAK.
164
164.
Calculating The UHF Alignment
or Calculating the UHF Alignment
163. Set the level to +5 dBm.