Nellis Tower PMI Report 2023 (3of4).pdf
PDF 6 MB Posted
- Attached to
- Antenna Preventative Maintenance
- Solicitation number
- FA486126Q0028
About this file
This is a test and inspection report for transmission lines, antennas, tower, and mounting hardware at Creech AFB, dated September 14, 2023. The RF survey was conducted using an Anritsu MT8212B Cell Master to perform Distance-to-Fault (DTF) and Return Loss measurements on cables and antennas operating in the 400-479 MHz frequency range. The testing methodology established that 15 dB or better return loss represents a common acceptable system limit for cable and antenna systems. Transmission lines were identified and labeled with color tape and engraved metal tags for future reference and maintenance purposes.
Testing results indicate that the RX antenna, TX Antenna 1, TX Antenna 2, and Building 10309 antenna all demonstrated passing return loss values within the 400-479 MHz frequency band. However, TX Antenna 3 initially failed testing and was found to have bad measurement values; per customer direction, the transmission line was relocated to a spare antenna on a secondary tower (Tower 2), which subsequently passed all tests. Cable and antenna mounting hardware was verified to be securely fastened. Metal identification tags were installed at antenna cable endpoints and inside the site building to facilitate future maintenance and troubleshooting operations.
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Table of Contents
Objective
Methodology
Results
Site Photos
Conclusion
Sept 14th, 2023
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 Creech AFB. In addition to testing, the transmissions lines were identified and labelled with color tape and engraved metal tags.
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 368ft
TX 1 Return Loss
TX Antenna 2 Distance-to-Fault Test indicates typical measurement value for a load/antenna at 369ft
TX Antenna 2 Return Loss
TX Antenna 3 Distance-to-Fault Test indicates a bad measurement value for a load/antenna at 364ft, at customer’s direction line was relocated to antenna on secondary tower. See results below
TX Antenna 3 Return Loss Test indicates failing values for frequencies between 400 to 479 Mhz. At customer’s direction, moved cable to another antenna, new test result below.
TX Antenna 3 (NEW) Distance-to-Fault Test indicates typical measurement value for a load/antenna at 256ft
TX Antenna 3 Return Loss
Bldg 10309 Antenna Distance-to-Fault Test indicates typical measurement value for a load/antenna at 175ft
Bldg 10309 Antenna Return Loss
Site Photos
Main Site Shelter Entry
Main Site Shelter Entry cont.
Main Site, Tower 1
Main Site, Tower 1 cont.
Antenna Label, typical
Tower 1, RX Antenna
Tower 1, TX Antenna 1
Tower 1, TX Antenna 2
Tower 1, TX Antenna 3 (Bad)
Main Site, Tower 2
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. TX3 antenna was found to be bad, per customer line was transferred to spare antenna on secondary tower. Antenna tested good after swap. Metal tags were installed at the antenna ends of the cables as well as inside the site building. Cable and antenna mounting hardware was securely fastened.
Sincerely,
File details come from the government source that posted it. Updated .