Attachment H (Antenna Sweep Display Examples).pdf
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- Attached to
- Wolf Mtn. Communication Site Build
- Solicitation number
- S-73000-00008156
- Issued by
- Lane County, Oregon
About this file
This document is an attachment providing examples of antenna sweep display readings related to a state and local contract opportunity for the construction of a new radio communications facility for public safety on Wolf Mountain in the Willamette National Forest in Oregon. The attachment demonstrates the acceptable and unacceptable sweep profiles for various feedline and antenna conditions, including distance to fault, return loss, and cable loss. The related state and local contract opportunity, titled "Wolf Mtn. Communication Site Build", involves the construction of a new transmission tower and ancillary facilities. No additional details are provided regarding response dates, due dates, award dates, or the contract term.
The document does not contain information about pricing terms, set-asides, incumbents, funding requirements and sources, or other salient commercial details. The focus is solely on the technical specifications and sweep display examples relevant to the radio communications equipment and infrastructure to be installed as part of this state and local construction project.
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Text version
ODOT SMOTP Appendix
Anritsu Sweep Display Examples
Feedline Distance to Fault Open - Acceptable Sweep - Sweep shows gradual rise up to the end of the Feedline (open or short). The display shows the end of the cable at 67.88’.
Feedline Distance to Fault Open - Acceptable Sweep - Sweep shows gradual rise up to the end of the Feedline (open or short). The display shows the end of the cable at 72.97’. Notice that “smoothing” is used by the Anritsu on this display.
Feedline Distance to Fault Open - Suspect Sweep - Sweep shows gradual rise up to the end of the Feedline (open or short) EXCEPT for the high peak a~9’. This could be a kink, bad connector, etc. in the line. Further investigation including inspecting the cable around that distance from the test device is necessary.
Feedline Distance to Fault Load - This sweep is for future use. It will be very similar to the DTF (short/open) reading, but will be affected the return loss of the load.
Feedline Return Loss Load - Acceptable Sweep - RL is BELOW 30 dB, and the trace is relatively smooth with no wild deviations.
Feedline Return Loss Load - Acceptable Sweep- RL is BELOW 30 dB, there are deviations. Feedline length can impact the return loss vs. frequency.
Feedline Return Loss Load - UNACCEPTABLE Sweep - RL is not below 30 dB, there are serious deviations in the RL.
Loos to
Feedline Cable Loss to Open (or short) - Acceptable sweep - This is a sweep that needs to be looked at carefully. This is a 7/8” Heliax that is ~100’ long, with a ½” jumper at the end. Factory data says .449 dB of loss for 100’ at 150 MHz, adding 4 connectors and ~10’ of jumper, this is OK.
Feedline Cable Loss to Open (or short) - UNACCEPTABLE sweep - If the sweep show negative loss (as in gain), there is an error in the Anritsu setup. This should NEVER be acceptable, and all other sweeps for that site become suspect!
Feedline Return Loss to Antenna (System) - Acceptable sweep - This is a somewhat subjective sweep at times. It is highly influenced by the antenna type, and some environmental factors. This is a good sweep of a Bluebird antenna - All sweeps must meet at least 14 dB (1.5:1 VSWR) within the passband of the antenna to be acceptable. Of the two sweeps below, sweep one is the antenna only in a quiet RF environment. Sweep two is installed on Lime Hill in a high RF environment. Both pass, but you can see the effect of nearby RF, feedline, etc.
Feedline Return Loss to Antenna (System) - Unacceptable sweep - This is an ANT-150 antenna that is bad. Return Loss is above 14 dB.
Feedline Distance to Fault System - This sweep is for future use. It will be very similar to the DTF (short/open) reading, but will be affected the return loss of the antenna as well. In this example, M1 is the end of the feedline, the rest up to M2 is the Anritsu trying to “interpret” the elements of the Bluebird antenna connected to the feedline.
SAMPLE ANTENNA SWEEP PROFILES - Here are sweep profiles for the most used antennas we are installing for reference….
File details come from the government source that posted it. Updated .