ADTRAN 12804108L1A, Системное руководство

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TRACER 4108/4208 System Manual Section 6 Troubleshooting Guide
612804208L1-1B © 2003 ADTRAN, Inc. 59
identity potential line-of-site obstacles, properly size antenna dishes, and determine minimum
antenna dish heights above the earth.
2. Setup all of the TRACER hardware on a workbench. ADTRAN recommends that the actual cables
used in the permanent installation be used in the workbench setup. A rigorous workbench
“simulation” of the link will help alleviate and avoid time-consuming errors.
3. Examine the
PLAN A
and
PLAN B
LEDs on the front panel of each unit. These LEDs indicate the
frequency plan for each TRACER 4108/4208 unit. The frequency plan (Plan A, Plan B) LED
should be the opposite on the TRACER 4108/4208 units.
4. Verify that both ends of the link are configured for the same RF Bandplan (1, 2, or 3). See
>TRACER System Options > RF Bandplan on page 48 for more details.
5. Verify that both ends of the link are configured for the same number of active T1 ports. See
>TRACER System Options >Active T1 Ports on page 49 for more details.
6. Attach the RF coaxial cables to be used in the permanent installation to the N-type connectors on
the back of the TRACER 4108/4208 unit. Attach the other end of the coaxial cable(s) to an RF
power meter or spectrum analyzer, if either is available. The power measured by the
meter/analyzer will be the RF power available at the input of the antenna. The TRACER
4108/4208 unit is programmed at the factory to output approximately 100 mW (20 dBm) of RF
power. The actual power level measured by the meter/analyzer will be less than 100 mW due to RF
losses through the coaxial cable, and is a function of the cable type and length being used. In any
event, the power level at the output of the coaxial cable should be a significant fraction of 100 mW.
A power meter/analyzer reading that is not on the order of at least tens-of-milliwatts could be an
indication of any combination of either unsuitable RF, or faulty, or unreasonably long coaxial
cable.
7. Resolve all RF coaxial cabling errors before proceeding.
8. Attach the RF coaxial cables to a high-quality attenuator, if possible. If you do not have an
attenuator, attach the coaxial cables to the antennas to be used in the permanent installation. If the
installation antennas are not available, small, inexpensive dipole or patch antennas can be used for
verification purposes. If an adjustable attenuator is being used, dial in the amount of attenuation
that corresponds to the path loss value expected for the microwave link in which the TRACER
hardware will be installed. The path loss value can be calculated from a knowledge of the path
length, or provided by a path study. Remember to subtract both antenna gain values from the
attenuator level if these values have not already be accounted for.
9. After setting up the RF pieces, examine the
RF DOWN
LED on the front panel of each TRACER
4108/4208 unit. If the
RF DOWN
LED is illuminated (red), the corresponding TRACER
4108/4208 is not receiving a suitable RF signal from the other TRACER 4108/4208 unit. In this
case, the receiving TRACER 4108/4208 is either receiving a very weak signal, or no signal at all.
If the
RF DOWN
LED is not illuminated, then the TRACER 4108/4208 units are receiving a
ADTRAN provides a wireless link planning tool on our website. This link budget tool is
constructed as an easy to use spreadsheet with dropdown menus so that the user can
quickly change any of the link parameters (antenna size, coaxial cable type and length,
frequency band, link distance, etc) and instantly see how the microwave path availability is
affected. This tool is available at
www.adtran.com/wireless and can be used online or
downloaded for standalone use.