User's Manual
Table Of Contents
- 1. General Description
- 2. Installation and Operation
- 3. Options
- 3.1 T01 Programmable Channel Spacing
- 3.2 T02 Programmable CTCSS encoder/decoder
- 3.3 T03 Programmable DCS/CTCSS encoder/decoder
- 3.4 T05 Balanced and Isolated VF plus E&M
- 3.5 T06 Simplex Changeover Relay
- 3.6 T08 VF Delay
- 3.7 T09 300Hz Upgrade HPF Filter
- 3.8 T10 Power Save Mode
- 3.9 T11 Combined Options
- 3.10 T12 External Reference Oscillator Input
- 3.11 T13 Local Speaker, Mic Socket and Front Panel Mute
- 3.12 T14 Local Channel Change
- 3.13 T16 1PPM Frequency Stability
- 3.14 U69 Extended Temperature Range Verification
- 3.15 T19/26 Line Interface Board.
- 3.16 T29 Balanced and Isolated VF plus E&M
- 3.17 T31 Network Adapter
- 3.18 T34 Ethernet option
- 3.19 T36 Option - TX Ref Oscillator input and Modulator
- 6. MX800 Base Station Fault Finding Procedure
- 7. Appendices
- 7.1 MX800 Interface Connections
- 7.2 CN2 DB9 Female Monitor Connector
- 7.3 CN3 DB25 Female Digital I/O Connector
- 7.4 MX800 Specifications
- 7.5 Channel Select DIP Switch Settings
- 7.6 MX800 Model Number Configuration Guide
- 7.7 MX800 System Applications
- 7.7.1 Conventional base station/repeater
- 7.7.2 Link transceiver
- 7.7.3 Data transceiver
- 7.7.4 Paging transmitter
- 7.7.5 Trunking Base Station
- 7.7.6 Systems base
- 7.7.7 Repeater with Morse ID
- 7.7.8 Simplex base station
- 7.7.9 Duplicated base station
- 7.7.10 Power Save base station
- 7.7.11 Tone key base station
- 7.7.12 Voting base station
- 7.7.13 Simulcast base station
- 8. Superseded Technical Information
- 9. Drawings
MX800 Transceiver Superseded Technical Information
frequencies. (Note that 'Continuous Update Enabled' on the MXTOOLS
channel screen should be ticked for these tests)
Do not connect Exciter RF drive output CN1 to PA.
Procedure:
1. Remove PA top cover. Measure resistance of thermistor between CN4-
6 and CN4-4, this should be approximately 2kΩ. Connect DC power
lead and 10-way connector from MX800. Connect PA RF output to RF
power meter and PA RF input (CN1) to RF signal generator.
2. Set signal generator to centre frequency of PA under test and reduce RF
drive level (from signal generator) to zero. Switch DC power on and
check that supply is present on L9. Assert PTT (check that no output RF
power is emitted from the PA) check that the 13.8V supply is switched
through to the Hybrid on pin adjacent to RF input and that 5V is
switched to the Hybrid on the next pin along (pins not numbered on
Hybrid).
3. With PTT ON measure the PA bias current at the Gates of the FET’s.
The Bias current is band dependent. This is done by monitoring the
current drain of the whole PA with CN1 disconnected. Link the gate of
TR2 to GND. Measure current consumption (VHF High Band 200mA
,UHF 400mA.) This can be adjusted by RV2. Measure gate volts ≈ 3.4V
Remove link from TR2. Measure current consumption, adjust RV1 so
that current is 2Amp total (VHF & UHF). Measure gate volts ≈ 3.9V
4. With PA transmitting at 50W into 50Ω load measure DC volts FWD
power sense CN4-8 and REFL power sense CN4-5. These voltages
should be approx. 2.8V and <250mV respectively. Reduce RF drive
until PA output is 10W and disconnect PA RF output cable. Measure
DC voltage on CN4-8 and CN4-5 again. These should now both read
lower approximately 1V. Remove PTT.
© SPECTRA ENGINEERING 2008 Revision 4.3.1B
110