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 59
Spectrum Analysis
It is occasionally useful to capture a baseline measurement of the newly installed
antenna before the DCU becomes operational. This is particularly true if the
antenna is suspected of potentially having issues due to a nearby transmitter.
A spectrum analyzer should be connected to the lower end of the coax and tuned to
listen in the 450-470 MHz band. If the planned frequencies are known, particular
scrutiny should be given to those channels to see if any strong transmissions are
within the immediate vicinity of those frequencies.
Measurements should be made with the spectrum analyzer and a baseline noise
level recorded around the frequencies of interest.
Measuring Earth Ground
It is important to maintain a solid Earth ground for lightning protection. Failure to
maintain proper ground can put the AC source, people, and nearby equipment at
risk of lightning damage. After inspection of the bonding clamps, the resistance to
ground at the DCU grounding point should periodically be tested. A solid
connection to ground can be lost over time. It is easily checked.
Required Equipment:
• Earth ground resistance meter capable of measuring 10 Ohms +/- 1.5%
Procedure:
1. Follow the procedure provided with the tool.
2. Ensure the following are true:
• All bonding clamps are in place.
• The resistance to ground from the DCU ground point to Earth ground is
10 Ohms or less.
Testing the Backhaul
If the DCU has been known to have difficulty staying on line, or moving data
reliably, a deeper investigation of its backhaul may be necessary. The tester may
wish to determine if the backhaul is working at all, or if the backhaul is performing
as expected under heavy load conditions.
Functional Testing
Tools Required:
• A laptop (or tablet) computer equipped with a cell card.