User Guide

CCS Technical Documentation Troubleshooting
NPM-2NX
Issue 1 07/02 ãNokia Corporation Page 39
If the cable losses are calibrated correctly the RSSI reading should give reasonable result
(-80 dBm +/- 2 dB). Please note that RSSI result is valid only if there has not been RX
calibration attempts for the faulty phone. If the RSSI level is several dB's lower go to
Step 2 (Local oscillator checking).
Step 2. Local oscillator checking
Carrying out this step VCO signal of 1st and 2nd mixers can be checked. 2nd mixer RX
VHF VCO frequency is constant 266.4 MHz but for the 1st mixer UHF VCO frequency
depends on the channel. The UHF VCO frequencies for the 1st mixer are:
Channel 512: 2063.4 MHz
Channel 661: 2093.2 MHz
Channel 810: 2123.0 MHz
1) Set phone receiver to continuous mode using Phoenix.
2) Set spectrum analyzer settings as following:
- Center frequency: 266.4 MHz, Span: 200 kHz
- RBW: 3 kHz, reference level: 0 dBm
3) Connect spectrum analyzer probe on the inductor L818 and record RX VHF VCO signal