User Guide

Appendix A: RF Troubleshooting
Nokia Customer Care
Company Confidential
Copyright © 2005 Nokia. All rights reserved
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5. DOES THE PHONE HAVE A RELIABLE CONNECTION TO THE NETWORK (GSM)?
This section refers to a situation when the phone registers to the GSM-network and is capable to make a call, but
the call is not reliable even if the GSM-network field strength is strong. The phone call is maybe disconnected or
interrupted.
5.1 GSM receiver Bit Error Rate (BER) ok?
• This test needs a GSM communication tester and if there is no that kind of tester available
continue troubleshooting in section 3.2 “
Does the phone give realistic RSSI-values?”.
• Attach the phone to the product specific test jig and a GSM communication tester to the
RF-coupler. Coupler attenuation should be also taken into account during measurements. This
measurement should be done in an RF shielded box.
• Close the shield box hatch.
• Make a GSM call against the tester
• Settings to the tester have to be done according to the 3GPP specifications:
- Set base station downlink power to -102 dBm
• Bit Error Rate should be less than 2 %
5.1.1 Does the phone give realistic RSSI-values?
• See section
3.2. “Does the phone give realistic RSSI-values?”
5.1.2 Hinku (N7500) or RAP3G (D2800) faulty?
• RAP3G is not possible to replace
5.2 GSM transmitter power levels and transmit frequency ok?
• See section
3.1. “GSM transmitter power levels and transmit frequency ok?”
5.3 GSM Transmitter phase error ok?
• See section
3.3. “GSM Transmitter phase error ok?”
5.4 GSM (GMSK) modulation spectrum ok?
• See section
3.4. “GSM (GMSK) modulation spectrum ok?”
5.5 TX power vs. time ok?
• See section
3.5. “TX power vs. time ok?”
6. DOES THE PHONE HAVE A RELIABLE CONNECTION TO THE NETWORK (WCDMA)?
This section means situation when the phone registers to the WCDMA-network and is capable to make a call, but the
call is not reliable even if WCDMA-network field strength is strong. The phone call is maybe disconnected or
interrupted.