User's Manual

The documentation should include a single-line diagram (such as Figure 5-9) including every

component of the base station installation. Labels on the diagram(s) should correspond exactly

to the physical labels on the actual equipment (above).

A portable spectrum analyzer capable of viewing frequencies to 1 GHz is an invaluable tool for

system maintenance and troubleshooting. Arcwave has found that the Anritsu MS2711B, which

operates up to 3 GHz, works very well in the field and is considerably more portable and less

expensive than lab spectrum analyzers. Whatever instrument is employed must have a method

of capturing traces, whether it is a digital capture of an LCD screen (the Anritsu) or the

traditional Polaroid of a CRT display.

At the time of system turn-up and a small number of pilot subscriber installations are complete

and active, spectrum analyzer traces should be captured and included in the system

documentation package. Three are three important spots in the system, which should be

captured. Following are examples of each:

All downstream 12 dB tap points (upconverter outputs)

All upstream 12 dB tap points (upstream input to the W-CMTS)

All upstream inputs to the W-CMTS (requires taking the sector out of service for the trace

capture)

5.7.1 Downstream 12 dB Tap points

Downstream 12 dB tap points are installed in the equipment room at the output of the internal or

external Upconverter (or at the output of any splitter at the output of an Upconverter), just prior

to the IF coaxial run to the lightning protector and thence to the Hub Transceiver.

Spectrum analyzer traces should be captured and saved at each of these points:

500

505

510

515

520

525

530

535

540

545

550

Spectrum Analyzer

BVT D2

Frequency (500.0 - 550.0 MHz)

Partially overdriven

Figure 5-18: Example of Downstream IF at the Upconverter output, which is overdriven.

The 12 dB tap point in one installation’s Downstream #2 is shown in Figure 5-18. The

downstream center frequency (upconverter output) is 523 MHz.

June 2003 Page 5-21