Technical Manual

Table Of Contents

56 D C U M a i n t e n a n c e a n d O p e r a t i o n M a n u a l

Calibrating the DCU’s RSSI Measurement

This test should be run initially upon installation, and periodically (every 5 years).

It should be run on a day when the outdoor temperature is reasonable.

Tools required:

• A laptop (or tablet) computer equipped with a cell card

• A calibrated spectrum analyzer (SA) with real-time signal capture

• A signal splitter

• Two identical lengths of coaxial cable which are short

1. Use a browser on a laptop or tablet computer to login to the utility's

corporate network, and login to a session of AclaraONE.

2. Check the status of the DCU to determine if it is considered on-line. Set it to

on-line if it is offline.

3. From the field data identify a target meter that appears to have a good signal

strength and perform reliably well.

4. Disconnect the antenna from the DCU port and install a 1:2 signal splitter.

Use one length of cable to connect the signal splitter to the DCU port. Use

the other identical cable to connect the other port of the signal splitter to the

spectrum analyzer.

5. Use AclaraONE’s Service And Diagnostic Tool to issue a trace route

command to a nearby DCU.

6. Note the response time, response channel, and signal strength as reported by

the DCU to the headend in the trace route response. Subsequent pings of the

same target should provide similar results. Start SA recording. Repeat the

trace route test to ensure the command results in a response that is captured

by both the DCU and the spectrum analyzer. End SA Recording.

7. Examine the results of the trace route and compare the RSSI value reported

by the DCU under test to the signal strength reported by the signal analyzer.

Adjust the DCU RSSI calibration and repeat the Steps 5-6 as needed until

the DCU’s signal strength value agrees with the spectrum analyzer.

8. Swap the two feeds from the signal splitter and rerun teps 5-6 to ensure the

signal splitter has not introduced a bias. If the measurement is now

different, make adjustments based on the average of the two.

9. Note the changes to the RSSI calibration in the electronic and paper

maintenance logs.

10. Remove the signal splitter and restore the coaxial connection.