Required Test Equipment; Tuning A 700/800 Mhz Duplexer; Tuning A Vhf Duplexer - Motorola GTR 8000 Manual

Tuning is performed by injecting RF signals and making tuning adjustments (using the tuning rods and trimmer
screws) while monitoring for maximum or minimum readings on the RF millivoltmeter. Field tuning the duplexer
module requires the following general adjustments:
• Tune high-pass/low-notch cavities for maximum pass and reject response
• Tune low-pass/high-notch cavities for maximum pass and reject response
• Check high-pass/low-notch and low-pass/high-notch cavities for insertion loss
• Check high-pass/low-notch and low-pass/high-notch cavities for isolation

5.9.2 Required Test Equipment

Tuning of the duplexer module requires the following test equipment:
• RF Signal Generator - Aeroflex 3900 Series Service Monitor
• RF Millivoltmeter (Boonton 92E or equivalent)
• 50 Ohm N-type terminator
• Tuning tool (5/32" x 4" screwdriver) (UHF)
• Male-to-Females N-Type "T" connector (UG-107B/U or equivalent) (VHF)
• Slotted screwdriver (VHF)
• 3/32" Allen wrench (VHF)
• Tuning tool (thin blade) (VHF)
• N-to-N bullet connector (UG29A/U or equivalent)
• 7/16" Nutdriver (UHF)
• 7/16" Open End Wrench (UHF)
• N-to-BNC Adapter (UG349A/U)
• N-to-N Connector (UG57B/U)

5.9.3 Tuning a 700/800 MHz Duplexer

No field tuning is needed on a 700 or 800 MHz duplexer. The duplexers are pre-tuned to operate over the entire
sub-band.

5.9.4 Tuning a VHF Duplexer

The following procedures are most easily performed with the duplexer module removed from the rack or cabinet.
Know the transmit and receive frequencies for the particular base radio before beginning.
If the duplexer module is tuned according to instructions and does not meet specifications for return loss, insertion
loss, and/or isolation, the duplexer must be returned for repair.
6871022P86-A - November 2012
5.9.2 Required Test Equipment
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