Technical Manual

Testing the DCU
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 55
Plot the results, and examine for omnidirectionality, as well as expected
signal strength.
Measurements taken at 3m or 10m can be compared to the table below for
anomalies.
Measurements taken at some distance must be compared to a propagation
study.
Measurements should be plotted (superimposed) on a satellite image and/or
street map.
Measurements taken at the same location but at different points in time
should have the same signal strength. If they don't agree, there may be
weather related path losses, multiple transmitters operating at the same
frequency, or some malfunction of the signal generator.
Interferer Test
If it has been observed, either through physical inspection, or because of
unexpected performance problems, that a new 3rd party transmitter may be
causing interference with the transmitter’s or receiver's performance of the DCU,
an interferer test is warranted.
Tools Required:
• A portable spectrum analyzer with real-time signal capture
User the following procedure to perform an interferer test.
1. Identify the frequencies in use by the DCU. The DCU Maintenance and
Operation Manual describes a number of commands that can be used to
obtain this data from the DCU directly.
2. Based on the underlying scenario, choose to either use the DCU antenna
and cable or use the Signal Analyzer’s own antenna. Connect the antenna to
the Signal Analyzer's antenna port.
3. Place the Signal Analyzer in waterfall mode and collect data for at least 15
minutes. The SA should be tuned to capture data around the DCU transmit
(and/or receive) frequencies.
4. Save the findings.
5. Use the results to quantify the severity of the interference.
6. Reconnect the DCU antenna cable (if it has been removed) and reapply the
waterproofing.
Conducted
Power (W)
Antenna
Gain (dBi)
ERP
(W)
EIRP
(W)
dBµV/m
@ 3m
dBµV/m @
10m
1.0 7 3 5.0 132.2 121.7
1.5 7 4.6 7.5 134.0 123.6
2.0 7 6.1 10.0 135.2 124.8