Vhf Tuning Procedures; Calculating Proper Vhf Alignment Frequency; Calculating The Vhf Alignment Frequency For A Single Receive Frequency; Calculating The Vhf Alignment Frequency For Multiple Receive Frequencies - Motorola ASTRO 25 GTR 8000 Manual

MN003286A01-E
Chapter 5: GTR 8000 Base Radio Optimization
• Torque driver capable of delivering 12 in-lb of torque and 10 mm deep well socket
• Tuning probe - Motorola Solutions Part No. 3082059X01, p/o TRN4083A tuning kit
• Flat-blade screwdriver
NOTICE: An R2600 Communications Analyzer can both generate and measure simultaneously.
A service monitor may be used for either the generator or the monitor function, but not both
simultaneously. When using service monitor as the signal generator, RF signal must be taken
from the antenna port.
5.9.1

VHF Tuning Procedures

VHF tuning procedures include the following:
• Calculating Proper VHF Alignment Frequency on page 160
• Preparing the Equipment for VHF Alignment on page 161
• Tuning The VHF Preselector on page 161
5.9.1.1

Calculating Proper VHF Alignment Frequency

Use either Calculating The VHF Alignment Frequency For a Single Receive Frequency on page 160
Calculating The VHF Alignment Frequency for Multiple Receive Frequencies on page 161
the VHF alignment frequency generated by the signal generator.
5.9.1.1.1

Calculating The VHF Alignment Frequency For a Single Receive Frequency

When and where to use: For a base radio with a single receive frequency, calculate the frequency of
the alignment signal as follows:
Procedure:
1 From the site documentation or the Configuration/Service Software (CSS), determine the
receive frequency.
2 If the frequency is ≤148 MHz or ≥156 MHz, subtract 250 kHz. Otherwise, note the actual
frequency.
Step example: If the receive frequency is 138.575 MHz, subtract 250 kHz because the
frequency is less than 148 MHz: 138.575 MHz – 250 kHz =138.325 MHz.
3 If the preselector is Range 1 (136–154 MHz), determine the alignment frequency as follows:
If frequency (from Step 2) is > 152 MHz, alignment frequency = 152 MHz.
Otherwise, use actual frequency from Step 2.
4 If the preselector is Range 2 (150–174 MHz), determine the alignment frequency as follows:
If the frequency (from Step 2) is < 152 MHz, alignment frequency = 151 0.75 MHz.
If frequency (from Step 2) is > 172 MHz, alignment frequency =172 MHz.
Otherwise, use actual frequency from Step 2.
160
or
to calculate