Nellis Tower PMI Report 2024 (4of4).pdf
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- Antenna Preventative Maintenance
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- FA486126Q0028
About this file
This is a technical inspection report documenting RF survey results for tower and antenna systems at Nellis Air Force Base, dated September 17, 2024.
The report presents findings from Distance-to-Fault (DTF) and Return Loss measurements conducted on transmission lines, antennas, mounting hardware, and towers using an Anritsu MT8212B Cell Master instrument. Testing was performed on five antennas across multiple locations: one RX antenna and three TX antennas on Tower 1, one TX antenna on Tower 2, and one antenna at Building 10309. All tested systems demonstrated passing return loss values within the 400-479 MHz frequency range, with measurements exceeding the standard 15 dB minimum threshold. Specific findings include RX antenna performance at 390 feet with acceptable load characteristics, TX Antenna 1 and 2 measurements at approximately 102-103 meters showing proper operation, and TX Antenna 3 at Building 10309 at 94.19 meters meeting specifications. However, one antenna on Tower 1 (TX Antenna 3) was identified as incompatible with the Harris trunking system operating frequency and requires replacement. The report documents that cable and antenna mounting hardware were found to be securely fastened, with supporting photographs of shelter entry points, tower installations, antenna configurations, and building infrastructure provided as visual documentation of the inspection process.
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Table of Contents
Objective
Methodology
Results
Site Photos
Conclusion
September 17, 2024
Nellis AFB
RE: Tower / Antenna PMI
Objective The objective of this RF survey was to test and inspect the transmission lines, antennas, tower, and mounting hardware for Nellis AFB.
Methodology Cables and antennas were tested with an Anritsu MT8212B Cell Master using Distance-to-Fault and Return Loss measurement tests. Distance To Fault (DTF) is a performance verification and failure analysis tool used for antenna and transmission line service and maintenance. DTF displays RF return loss or VSWR data versus distance. The effects of poor connections, damaged cables, or faulty antennas are quickly identified. Since DTF automatically accounts for attenuation versus distance, the display accurately indicates the return loss or VSWR of the antenna. These measurements show the user the match of the system and if it conforms to system engineering specifications. A poorly matched antenna will reflect costly RF energy which will not be available for transmission and will instead end up in the transmitter. This extra energy returned to the transmitter will not only distort the signal, but it will also affect the efficiency of the transmitted power and the corresponding coverage area. While different systems have different acceptable return loss limits, 15 dB or better is a common system limit for a cable and antenna system.
Results Screenshots provided are the output of Anritsu’s Line Sweep Tools application using the measurements collected on site.
RX Antenna
Distance-to-Fault Test indicates typical measurement value for a load/antenna at 390ft
RX Antenna Return Loss Test indicates passing values for frequencies between 400 to 479 Mhz
TX Antenna 1 Distance-to-Fault Test indicates typical measurement value for a load/antenna at 102.91m
TX 1 Return Loss
TX Antenna 2 Distance-to-Fault Test indicates typical measurement value for a load/antenna at 103.68m
TX Antenna 2 Return Loss
TX Antenna 3 Distance-to-Fault Test indicates typical measurement value for a load/antenna at 64.92m
TX Antenna 3 Return Loss
Bldg 10309 Antenna Distance-to-Fault Test indicates typical measurement value for a load/antenna at 94.19m
Bldg 10309 Antenna Return Loss
Site Photos
Main Site Shelter Entry
Main Site Shelter Entry cont.
Main Site, Tower 1
TX ANTENNA 3
RX ANTENNA
TX ANTENNA 2
TX ANTENNA 1
Antenna Label, typical
Tower 1, RX Antenna
Tower 1, TX Antenna 1
Tower 1, TX Antenna 2
Tower 1, TX Antenna 3 (Bad) Antenna found to be wrong band for Harris’ trunking system. Recommend to replace antenna
Main Site, Tower 2
ANTENNA 5
ANTENNA 3
ANTENNA 4
Main Site Tower 2 cont.
Tower 2, TX Antenna 3 (NEW)
Tower 2, Antenna 4 (not connected)
Tower 2, Antenna 5 (not connected)
Bldg 10309 Tower
Conclusion Transmission lines and antennas were tested. Cable and antenna mounting hardware was securely fastened.
Sincerely,
File details come from the government source that posted it. Updated .