OPT014-1 BDA Testing Uplink Power and Gain

Uplink Power and Gain Test

Cleaned Lesson Transcript / Study Notes

The next test is the Uplink Power and Gain test.

This test helps determine how the BDA should be programmed for uplink operation.

The goal is to calculate the proper BDA uplink power, gain, attenuation, and squelch settings so that radio transmissions inside the building can reach the radio site correctly without overdriving the system.

1. Purpose of the Test

The Uplink Power and Gain test tells us how to program the BDA.

This test uses information from previous testing, especially the downlink isolation/system loss test.

The uplink system loss information is pulled into this test from the previous downlink isolation test.

2. Target Channel Power

In this example, the target channel power is:

6.8 dBm

With this uplink power output, the signal should arrive at the radio site at approximately:

-95 dBm

This calculation also takes into account the donor antenna and related system losses.

3. Radio Test Frequency

The radio test frequency is selected in the setup.

In this test, the radio will actually transmit on the selected uplink test channel.

The setup also shows where the previous downlink system loss result was selected.

An alternate method would be to perform a true uplink measurement. In that case, the technician would generate a signal into the donor antenna while someone measures the uplink signal at the tower site.

For this example, the previous Downlink Isolation Test result is selected and used.

4. Near Location Measurement

Next, go to the test point and key the radio from a near location.

The near location is close to the antenna system and represents the strongest signal the BDA should receive.

In this example, while keying the radio, the maximum input power is:

-43 dBm

This is the strongest, or “hottest,” signal the BDA should ever see from the DAS side.

Add this near-location measurement to the report.

5. Far Location Measurement

Next, relocate to a far location.

The far location should be as far away from the antenna system as possible while still remaining inside the building.

Collect the far-location data and add it to the report.

In this example:

The results show that the ALC range is acceptable, so the test passes.

6. Final Attenuation and Uplink Channel Power

The test results are used to determine the final BDA programming values.

In this example, no final attenuation is required.

The suggested uplink channel power is:

6.8 dBm

The selected final target power is rounded to:

7 dBm

7. Final Gain

The final gain is based on the far radio measurement.

In this example:

The BDA would be programmed with a final uplink gain of:

65 dB

8. Final Squelch

The final squelch setting is determined using the far uplink power.

The squelch should typically be set approximately 10 dB lower than the far uplink power.

The spectrum noise analysis must also be considered. The squelch should be at least 20 dB greater than the measured noise floor.

In this example, the acceptable squelch range is between:

A practical squelch value is selected within that range.

The final squelch setting used in this example is:

-80 dBm

Final Result

The Uplink Power and Gain test provides the values needed to program the BDA.

This test documents:

• Uplink test frequency
• Previous system loss reference
• Near radio input power
• Far radio input power
• Dynamic range requirement
• ALC/AGC range result
• Final attenuation
• Final uplink channel power
• Final uplink gain
• Final squelch setting

In this example, the BDA programming values are:

This is how the BDA will be programmed for proper uplink performance.