The next test is the Exterior Leakage Test.
This test verifies that the in-building DAS/BDA signal is not leaking outside the building at a level that could interfere with the outdoor public safety radio network.
1. Select the Workspace
To begin, make sure the correct workspace is selected.
The workspace should include:
- Public safety channels
- Test channels
In this example, the workspace includes the control channels for the radio system and the test channels.
The test channels should be in the same band as the public safety channels.
In this example:
- Public safety channels are in the 700 MHz band
- Test channels are also in the 700 MHz band
2. Create a New BDA Leakage Test
Go to the BDA test setup and create a new BDA test.
Select the workspace first.
Then choose the test type:
Leakage
Select the image for the test. A floor plan is best for this test because the technician needs to place test points around the exterior perimeter of the building.
Choose Custom, then drag and drop or upload the floor plan file.
Select Next.
3. Purpose of the Test
The purpose of the Exterior Leakage Test is to compare:
- The signal being amplified and radiated by the BDA/DAS
- The signal coming directly from the outdoor public safety tower network
The goal is to confirm that the outdoor macro network is stronger than the leaked in-building signal outside the building.
4. Place Exterior Test Points
Place test points around the outside of the building.
Good test point locations include:
- Exterior doors
- Exit doors
- Loading dock areas
- Stairwells on the outside of the building
- Any exterior wall or opening where signal may leak out
In this example, the technician places test points near:
- An exit door
- A loading dock
- Exterior doors
- Outside stairs
- Multiple sides of the building
Each test point should be approximately:
3 feet away from the building
This is the distance used to compare the outdoor network signal against the leaked DAS signal.
Once the test points are placed around the building, the test setup can be configured.
5. Select the Outdoor Network Frequency
Next, select the network outdoor frequency.
This represents the channels coming directly from the radio system/tower.
In this example, the selected outdoor network is the group of public safety control channels.
Then select the DAS test channel.
For this test, the DAS test channel should be a downlink protected channel.
In this example, the DAS downlink test channel is:
773 MHz
A frequency can also be added manually if needed.
6. Set the Power Difference Threshold
For this P25 Phase 2 system, the required power difference is:
15 dB
This means the outdoor network channel should be at least 15 dB stronger than the signal being radiated or leaked by the DAS outside the building.
In simple terms:
Outdoor macro signal must be 15 dB higher than leaked DAS signal.
Once this threshold is set, the leakage test setup is ready.
7. Download the Test to the Tablet
After the leakage test is configured, download it to the tablet.
The tablet will guide the technician through the exterior leakage test using the floor plan and test points.
8. Field Test Setup
For the field setup:
- Disconnect the donor antenna from the BDA.
- Add an attenuator to protect the equipment.
- Measure the downlink power from the tower on the donor antenna.
- Replicate that measured signal using a test signal generated by the transmitter.
The attenuator is used to protect the transmitter in case the BDA sends power upstream.
It is recommended to turn off the uplink HPA during this test.
The test channel must also be added into the BDA and configured the same way as the normal downlink control channel.
9. Replicate the Donor Signal
Measure the actual donor signal power.
Then use the CW generator to replicate that signal.
Compensate for the attenuator so that the BDA generates the test signal at the same power level it would normally use for live radio signals coming down from the tower.
This ensures the leakage test represents real operating conditions.
10. Run the Exterior Leakage Test
On the tablet, select the Exterior Leakage Test.
The test points should appear around the building on the floor plan.
Select a test point and begin the downlink measurement.
During the test, the transmitter should be generating the test signal into the BDA.
The scanner compares:
- The outdoor macro/donor signal
- The leaked DAS signal outside the building
The comparison is made between the selected outdoor network frequency and the DAS test frequency.
11. Add Results to the Report
After each measurement, add it to the report.
The result appears at the bottom of the screen.
The report will show:
- Peak measurement from the outdoor network
- Leaked DAS signal value
- Power difference between the two
- Pass/fail result
If the measured power difference meets the configured threshold, the test point passes.
For this example, the required threshold is:
15 dB
12. Add Location Comments
Comments can be added for each test point.
For example:
Northeast exterior door
This helps document exactly where the measurement was taken.
After adding comments, return to the results view to review the completed measurements.
Final Result
The Exterior Leakage Test confirms that the BDA/DAS signal is not leaking outside the building at a level that could interfere with the outdoor public safety network.
This test documents:
- Workspace used
- Public safety control channels
- DAS test channel
- Floor plan
- Exterior test point locations
- 3-foot measurement distance
- Outdoor macro signal level
- Leaked DAS signal level
- Required 15 dB dominance threshold
- Pass/fail result
- Location comments
In this example, the outdoor macro network must be at least 15 dB stronger than the leaked DAS signal at each exterior test point.