Service manual

2000 SERIES RECEIVER DECODER MODULE (RDM)
3-21
March 2000
Part No. 001-3139-502
Receiver SINAD Measurement
1. Adjust the RF generator for 100 µV into the receiver
with a 1 kHz tone at ±3 kHz (1.5 kHz at 900 MHz).
2. Connect a 16 ohm load and distortion analyzer to
J204 of the Interface Board.
3. Adjust R262 for 2.8V RMS.
4. Re-adjust RF level for 12 dB SINAD.
12 dB SINAD reading should be ≤ 0.35 µV.
Receiver Squelch Adjustment
1. Adjust the RF generator for 100 µV into the receiver
with a 1 kHz tone at ±3 kHz (1.5 kHz at 900 MHz).
2. Connect a 16 ohm load and distortion analyzer to
J204 of the Interface Board.
3. Adjust R262 for 2.8V RMS.
4. Set the RF generator output for 5 dB SINAD.
5. Adjust R222 on the Interface Board so the Receiver
just squelches.
6. Increase the RF generator output until the Receiver
unsquelches. Reading should be
≤ 10 dB SINAD.
Receiver Data Level Adjustment
1. Adjust the RF generator for 100 µV into the receiver
with a 100 Hz tone at ±1 kHz
(0.8 kHz at 900 MHz).
2. Insert voltmeter probes into J202 on the Interface
Board and connect to an AC voltmeter.
3. Adjust R235 to achieve 340 mV RMS.
Receiver RSSI Adjustment
NOTE: Use this procedure only when an audio analyz-
er is unavailable.
1. Adjust the RF generator for 0.29 µV into the
receiver with a 1 kHz tone at ±3 kHz (1.5 kHz at
900 MHz).
2. Adjust R261 in the receiver for 0.8V DC (±0.02V
DC) at TP3 for 800 MHz Receivers and 0.7V DC for
900 MHz Receivers.
Receiver Miscellaneous Tests (Optional)
Several additional tests may be performed on the
Receiver as listed below:
• Signal Displacement Bandwidth
• Adjacent Channel Rejection
• Offset Channel Selectivity
• Intermodulation Rejection
• Spurious Rejection
• Audio Response
• Audio Sensitivity
Perform the Test desired using the appropriate RF
Generators, modulation frequencies, levels, RS-232
levels and test probes following the latest TIA docu-
ment measurement procedures.
Handshake Test
1. Program a Multi-Net, portable or mobile for the fol-
lowing parameters.
Multi-Net
Home Repeater - Same as repeater number.
System Key - Same as repeater.
Status Channel - Same as repeater channel.
Home Channel - Same as repeater channel.
Encode ID - 1
Decode ID - 1
UID - 1
Site - 1
2. The RDM is in Normal Operation mode.
3. Key the radio several times on the programmed Sys-
tem/Group. Display should indicate “4” every time.
(Proper Tx/Rx antenna connections are assumed.)
Alarm Test
1. The RDM is now in Normal Operation mode.
2. Verify the front panel display does not indicate any
alarms (see Table 3-3).