User's Manual Part 2

ADCP-75-187 • Preliminary Issue 1B • November 2005 • Section 3: OPERATION
Page 3-12
© 2005, ADC Telecommunications, Inc.
Figure 3-8. Host Fwd Att Pop-Up Screen
4. Determine the appropriate value to enter for the Host forward path attenuator by
subtracting the required system output level (per system design plan) from the system gain
(77.5 dB for 800/900 MHz SMR, 78.1 dB for 800 MHz, and 78.3 dB for 1900 MHz) and
then adding the composite input signal level. The result (see sample calculation) is the
amount of attenuation required.
Atten = (System Gain) – (Required System Output Power) + (Composite Input Power)
5. Enter the attenuation value and click OK to close the pop-up screen and to make the
changes take effect.
2.4 Reference Procedure: Determine Output Signal Level at RU Antenna Port
The RF output signal level should be measured at the RU ANTENNA port to verify that the
composite signal level is at the expected level. Use the following procedure to determine the
power level:
1. Place the AC circuit breaker switch (at the RU power panel) in the open (OFF) position.
2. Disconnect the antenna cable from the RU ANTENNA port.
3. Connect a spectrum analyzer or RF power meter to the HU ANTENNA port. (Check the
input rating of the test equipment. Insert a 30 dB 100 W attenuator if necessary.)
4. Place the AC circuit breaker switch (at the RU power panel) in the closed (ON) position.
5. If using a spectrum analyzer, proceed to step 6. If using a power meter, measure the
composite signal power from the RU and then proceed to step 8.
6. Measure the RF level of a single carrier, such as the control channel, in dBm. Make sure
the resolution bandwidth of the spectrum analyzer is 30 kHz.
Note: The RF output signal level measured in this procedure should be approximately
31 dBm less than the output level specified for operation. This is because the factory
default setting for the remote forward attenuator is 31 dB. The final adjustment of the
system RF output signal level will be completed in Section 2.5