Troubleshooting guide

Bulletin 639519 • Revision D May 2009 9-1
Section 9
ATC300-1000 Using SMB Ports
9.1 No Devices Found
• See Section 8 for general discussion of ATC300-1000 issues.
• Verify using dc 2.1 bias tee. Andrew has two dc 2.1 bias tees:
ABT-DMDF-ADBA and ABT-DFDM-ADBA.
Any other bias tee may scramble the AISG signal.
• Verify dc 2.1 bias tee is correctly installed and on correct coax line.
• Verify AISG coaxial surge arrestors are correct type:
APTDC-BDFDF-DB, APTDC-BDFDM-DB or equivalent.
• Verify top smart bias tee is correctly installed and passes AISG.
• Verify TMA is an AISG smart TMA.
• Verify SMA/SMB cables are connected well and are passing 24 volts.
• A portable spectrum analyzer can be used to verify that the 2.176 MHz signal is present at
the SMB port. (Be sure analyzer can support 24 Vdc.)
9.2 Note on dc 2.1 Bias Tee
• The AISG signal is modulated to 2.176 MHz at the SMB port.
If the SMB port is connected to a smart bias tee, the signal may be scrambled and hamper
communication.
If an ordinary bias tee is used, the signal may be blocked.
Because of this, a dc 2.1 bias tee is recommended.