Verify Uplink Noise Test
Cleaned Lesson Transcript / Study Notes
The next step is the Verify Uplink Noise test.
Before running this test, the BDA has been unmuted, or the mute threshold has been removed. This allows the test equipment to see the full noise output from the BDA.
The service antennas are connected during this test, so the measurement includes both:
- Noise from the BDA
- Environmental noise picked up by the service antennas
1. Begin the Noise Capture
Select the proper test point and begin the capture.
During the capture, the scanner displays the uplink noise profile.
In the example, the display shows:
- The overall noise crown
- Noise associated with each programmed filter
This allows the technician to evaluate whether the BDA is contributing excessive noise into the uplink path.
2. Review the Noise Level
In this example, the measured noise level is approximately:
-55 dBm
The scan results are then reviewed in the configuration/results section.
The measured value is entered into the results field as:
-55 dBm
3. Apply Uplink Power and Gain Data
The test uses information from the previous Uplink Power and Gain test.
That information pulls in the system loss and path loss calculations needed to estimate how much noise will arrive at the tower site.
Based on the entered noise level and the previous uplink power/gain data, the system calculates the noise contribution at the tower.
4. Review Tower Site Noise Contribution
In this example, the calculated noise arriving at the tower is:
-156 dBm
This is well below the maximum allowed noise contribution.
Because the calculated noise contribution is below the limit, the result is acceptable.
Final Result
The Verify Uplink Noise test confirms that the BDA is not contributing excessive uplink noise to the public safety tower site.
This test documents:
- BDA mute threshold status
- Service antenna connection
- Environmental noise contribution
- Noise crown measurement
- Filter-related noise
- Measured uplink noise level
- Estimated noise arriving at the tower
- Pass/fail status
In this example, the measured noise level is approximately -55 dBm, and the calculated noise arriving at the tower is -156 dBm, which is well below the maximum allowed noise contribution.