Once the workspace has been created, the next step is to create a BDA test setup.
In Central, create a new BDA test setup and select the workspace that was previously created. From there, each individual test will be added.
The order of the tests is important because some tests depend on results or validation from earlier tests.
1. Signal to Building Test
Start with the Signal to Building test.
For this test, add a floor plan. If a roof diagram is available, that is preferred because the donor antenna candidates are usually evaluated from roof locations.
With the Signal to Building test, you will add the possible donor antenna locations. These are the candidate locations where the donor antenna may be installed.
Each donor location will be measured and rated.
The test will measure the P25 control channel.
This test also includes pass/fail criteria. If cable losses need to be compensated for, those values can be entered as part of the setup.
2. CW Antenna Verification Test
The CW Antenna Verification test generates a signal into the DAS and measures that signal at each intentional radiator, meaning each antenna.
This test verifies that:
- The DAS is complete
- Cable connections are properly made
- Antennas are functioning correctly
- Power levels are close to expected design values
This test must be completed before moving on to isolation testing.
3. Downlink Isolation Test
After the DAS has been verified as complete, the next step is the Downlink Isolation Test.
It is critical that the DAS has been verified as 100% complete before performing this test.
The setup includes a guided image showing where to place the transmitter and where the test point should be.
For this test, the transmitter is connected to the service side, and the measurement is taken at the donor side.
The test uses the downlink test channel so that testing does not cause interference on licensed public safety networks.
In the example, the BDA gain is assumed to be:
70 dB
Per NFPA, the isolation must be 20 dB greater than the gain of the BDA.
So in this example:
| Item | Value |
|---|---|
| BDA Gain | 70 dB |
| Required Margin Above Gain | 20 dB |
| Target Isolation | 90 dB |
This becomes the target isolation margin for the test.
4. Downlink Spectrum Noise Analysis
For the downlink spectrum noise analysis, set the start and stop frequencies to match the public safety band being tested.
In the example, the test is in the 700 MHz public safety downlink band.
The downlink noise measurement uses:
| Setting | Example Value |
|---|---|
| Start Frequency | 768 MHz |
| Stop Frequency | 775 MHz |
| Resolution Bandwidth | 10 kHz |
Because this is a noise measurement, the resolution bandwidth should be set to 10 kHz.
5. Downlink System Loss
The setup can also measure downlink system loss.
Select the control channel from the workspace.
Then enter the effective radiated power, also known as ERP, for the site.
In the example:
| Item | Value |
|---|---|
| Effective Radiated Power | 30 dBm |
| Donor Antenna Gain | 3 dB |
If donor transmit antenna cable loss, antenna gain, or other values are known, those can also be entered.
6. Uplink Isolation Test
Next, perform the Uplink Isolation Test.
This test also includes a guided image.
For uplink isolation, the transmitter is placed on the donor antenna side, and the measurement is taken on the service antenna side.
The test uses the uplink test channel.
In the example:
| Item | Value |
|---|---|
| Uplink Test Channel | 803 MHz |
| Assumed BDA Gain | 70 dB |
| Required Margin Above Gain | 20 dB |
| Target Isolation | 90 dB |
The uplink frequency range is set around the uplink public safety band.
Example settings:
| Setting | Example Value |
|---|---|
| Start Frequency | 798 MHz |
| Stop Frequency | 806 MHz |
| Resolution Bandwidth | 10 kHz |
7. Uplink Power and Gain Test
After uplink isolation, perform the Uplink Power and Gain test.
This test uses radios to determine what the BDA uplink power and gain settings need to be for the system to function correctly inside the building.
The test confirms that radio transmissions can reach the tower at acceptable levels without overdriving the tower receiver.
The guided image shows the test point and setup.
In the example, the test radio transmits on:
803 MHz
The grading parameters include the acceptable input power range at the radio site.
| Parameter | Example Value |
|---|---|
| Minimum Radio Site Input Power | -95 dBm |
| Maximum Radio Site Input Power | -75 dBm |
| Working Range | 20 dB |
This means the received signal at the tower should fall between -95 dBm and -75 dBm.
The setup also allows adjustment for:
- Donor antenna gain
- Cable loss
- Attenuator values
- Previous test results
- Uplink offset
The maximum uplink donor antenna power is:
37 dBm
This limit is based on 47 CFR Part 90.219, which governs signal boosters and BDAs.
Previous test results, such as downlink isolation or system loss, can be selected and pulled into this test.
8. Uplink Offset
The uplink offset accounts for additional gain or loss on the receive side of the public safety tower system.
This may be affected by:
- Antenna diversity
- Tower-top amplifiers
- Receive preamps
- Other receive-side circuitry
In the example, the receive side has:
20 dB greater gain
This offset must be considered when calculating proper BDA uplink gain and output power.
9. Verify Uplink Noise Test
Once uplink gain and power are set, verify that the BDA is not causing noise problems at the tower site.
There are two ways to do this:
- Use a remote spectrum monitor installed at the tower site.
- Measure noise directly from the BDA output into the scanner.
The test setup includes a guided image showing the test point.
In the example, the uplink frequency range is approximately:
798 MHz to 806 MHz
The maximum contributed noise value used in the example is:
-43 dBm
This is based on FCC on-channel noise limits.
Another reference value is:
-140 dBm
This is approximately 10 dB below the thermal noise floor and is used as a good baseline value.
The test can also pull information from previous tests to complete the setup.
10. Exterior Leakage Test
After the uplink noise test, perform the Exterior Leakage Test.
This test verifies that the BDA system is not leaking excessive RF energy outside the building.
A floor plan can be imported, or the guided image can be used.
For this test, the donor signal is replicated on a test channel and injected into the BDA. This causes the system to radiate at full power through the indoor antennas.
The technician then walks around the building perimeter with the scanner.
The purpose is to compare:
- The outdoor macro network signal
- The signal leaking from the in-building DAS
The outdoor network should dominate the leaked indoor signal.
This test is usually one continuous test point for the entire perimeter walk.
In the example:
| Item | Value |
|---|---|
| Generated Test Channel | 773 MHz downlink |
| Required Dominance | 15 dB |
| Measurement Distance | 3 feet from building perimeter |
| Channel Type | P25 Phase 2 |
The requirement is that the outdoor macro signal should be 15 dB stronger than the leaked signal measured 3 feet from the perimeter of the building.
11. Near-Far Test
The Near-Far Test verifies that two radios can operate properly when one radio is close to an antenna and another radio is farther away.
The problem scenario is this:
A near radio transmits very close to an indoor antenna. This strong signal can drive the BDA into saturation, causing the BDA to reduce gain through AGC or ALC.
While that is happening, a far radio must still be able to transmit through the BDA and reach the site radio with enough power.
This test confirms that the far radio can still meet the target power requirement.
In the example:
| Setting | Example Value |
|---|---|
| Test Frequency | 803 MHz |
| Decode Type | Phase 1 traffic decode |
| Transmitter Frequency | 803.0125 MHz |
The transmitter frequency is selected so that it falls within the same filter.
Attenuation between the BDA and scanner can be adjusted, and previous test results can be selected to pull in known values.
12. Live Antenna Verification
The Live Antenna Verification test is performed after the earlier CW antenna verification.
The CW test was used to validate that the DAS was connected and functioning. The live antenna verification becomes part of the acceptance test.
This test uses live signal readings and may overwrite the CW data previously captured.
The purpose is to confirm actual system performance after commissioning.
13. BDA Filter Configuration Test
Next, add the BDA Filter Configuration tests.
These are performed separately for:
- Uplink
- Downlink
Both tests include guided images.
The test verifies that the BDA filters are configured correctly and that the programmed frequencies are being amplified as expected.
Uplink Filter Configuration
For the uplink filter configuration test, add the test point and indicate where the transmitter will be connected.
The start and stop frequencies for the passband must line up with the programmed 12 kHz-wide channels.
Example uplink settings:
| Setting | Example Value |
|---|---|
| Start Frequency | 798.98125 MHz |
| Stop Frequency | 805.87 MHz |
| Attenuator | 5 dB |
| Cable Loss | 1 dB |
| Transmitter Power | 40 dBm |
| Preferred Margin | 4 dB |
All individual channels programmed into the BDA should be added, including:
- Public safety network channels
- Test channels
The optional noise threshold is not used in this example.
Downlink Filter Configuration
The downlink filter configuration test is set up separately.
Again, add the guided image, add the test point, and enter the proper start and stop frequencies.
Example downlink settings:
| Setting | Example Value |
|---|---|
| Stop Frequency | 775.0101875 MHz |
| Filters Added | Public safety filter and test channel filter |
Attenuation and field values can be adjusted during the test. If the expected field values are already known, they can be entered during setup.
14. Name the BDA
After all required tests are added and configured, name the BDA.
Once the BDA is named and saved, the BDA test setup is complete.
Final Test Setup Order
The recommended order from this lesson is:
| Step | Test |
|---|---|
| 1 | Signal to Building |
| 2 | CW Antenna Verification |
| 3 | Downlink Isolation |
| 4 | Downlink Spectrum Noise Analysis |
| 5 | Downlink System Loss |
| 6 | Uplink Isolation |
| 7 | Uplink Power and Gain |
| 8 | Verify Uplink Noise |
| 9 | Exterior Leakage |
| 10 | Near-Far Test |
| 11 | Live Antenna Verification |
| 12 | Uplink BDA Filter Configuration |
| 13 | Downlink BDA Filter Configuration |
| 14 | Name and save the BDA setup |
The completed BDA test setup can now be used to perform the commissioning tests in the field.