Step 2. Local Oscillator Checking; Fig 20 Gsm Rssi Measurement - Nokia RH-13 Series Troubleshooting Manual

RH-13
Troubleshooting
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 128:
Channel 189:
Channel 251:
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
Page 38
Figure 20: GSM RSSI Measurement.
2004.8 MHz
2029.2 MHz
2054.0 MHz
ãNokia Corporation
CCS Technical Documentation
Issue 1 11/02