MX800 Transceiver Technical Manual
© SPECTRA ENGINEERING 2006 Revision 4.2.3
56
TX Alignments
1. PTT the transmitter.
2. Using a signal generator, apply a 1kHz Tone with the line up
level as required (default -10dBm), injected into the rear RJ45
connector, pin3 & 4. (Balanced audio)
3. Disable AGC on Option Board JMP13 (Position 2-3)
4. Adjust TX input line gain RV5 to obtain 1 Vp-p at IC13 pin 1.
5. Monitor TX modulation depth and insure it is equal to the
nominal deviation level. If not just RV4 on the motherboard to
obtain correct level.
6. Enable AGC by linking in Jmp13 in position [1-2]
7. Using a signal generator, apply a Key tone to Audio level @-
10dB.
[–10dBm0] (Default –20dBM)
8. Adjust RV7 so that the combined audio and key tone signal are
set to the required onset compression level.
1Vp-p at IC13 pin 1. (JMP9 2-3)
(Default compression level are, audio -20dBm and key tone
signal is set to -30dBm)
9. Monitor TX modulation depth and insure it is equal to the
nominal deviation level. If not adjust RV4 on the motherboard to
obtain correct level.
RX Alignments
1. Using a 600ohm termination monitor RX line output level. This
output is located on the rear of the MX800, RJ45 Line I/O
connector pin 1 & 2 (balanced audio)
2. Set the receiver modulation frequency to 1kHz and the FM
deviation to nominal for the particular RF receive frequency of
the test channel. At a RF level of –60 dBm.
3. Remove JMP20 and adjust Line Output level RV4 to obtain
nominal line output level (-10dBm is the default level).
4. Fit JMP20 in positions [1-2] and remove JMP7
5. Adjust RV1 for so that the ratio of Key tone to Audio level @-
10dB. (–10dBm0)
6. Fit JMP7 in positions [2-3]
Two wire Mode only
7. Using an oscilloscope, monitor the audio on IC4 pin1 also insure
that Pin1&2 of SK5 Terminated to a 600ohms load.
8. Adjust RV2 for minimal Audio level on IC4 pin1. (Aprox
<5mV)
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