TM
FOR UNITS WITH SERIAL
NUMBERS EXCEEDING 110
(PCB REVISION 0198 ONWARDS)
11-38-0000
Synthesized UHF
Transceiver
User’s Handbook
Sea Air and Land Communications Ltd, Christchurch, New Zealand
11-38-0000 SYNTHESIZED TRANSCEIVER OPERATOR’S MANUAL
Issue 1138UA
Manual applies to 11-38s with serial numbers greater than 110 (PCB issue 01/98 onwards)
Page 1
11-38 SYNTHESIZED TRANSCEIVER
OPERATOR'S MANUAL
1.0
DESCRIPTION:
The Salcom 11-38 is a 1.2w UHF narrow band FM Transceiver
using ±5kHz deviation on the UHF 25kHz channel spaced bands, 406-430MHz and
450-475MHz. In addition a version using 12.5kHz channel spacing in the 450-
475MHz band (± 2.5kHz deviation) is available. The transceiver design is based
upon the separate 11-23 receiver and 11-24 transmitter and therefore has many
similarities. There are also many mechanical similarities to the crystal controlled
TR460 (10-84-0000) transceiver.
The 11-38 is supplied tuned to the requested frequency. Up to 16 independent
receive and transmit frequencies may be pre-programmed and selected by internal
DIP switches. The transmitter power output may also be internally adjusted to
between 50mW to approximately 1.2 Watts output.
2.0
OPTIONS:
Special options are available and can be ordered with the 11-38 or
retro-fitted by your supplier:
!
600O balanced input when T101 fitted.
3.0
SETUP INSTRUCTIONS
3,I
Deviation on data source:
When transmitting a constant level tone from
a modem or tone encoder use AF1 input (Comms connector pin 3). Monitor
the demodulated waveform on a modulation meter and set the line level
control AF1 (RV301) so that a clean sine wave is visible. Adjust the
deviation control "MOD" (RV304) for ±4kHz deviation with the modulating
source (i.e.modem idle tone), or ±2kHz for 12.5kHz bandwidth.
3.2
Deviation on speech source:
If an uncompressed varying level
modulation (i.e. speech) is being transmitted, then the AF2 input (comms
connector pin 13) can be used. RV303 (MIC) sets the sensitivity of the
microphone input and should initially be set to about 9 o’clock.
Set RV302 (AF2) for minimum distortion of the envelope when transmitting
maximum audio. Typically adjust this until clipping of the output waveform
is apparent and then reduce RV302 (AF2) until the signal is clean. Adjust
the deviation control (RV304) for the correct transmit deviation (± 3kHz for
25kHz systems and no greater than ± 2kHz for 12.5kHz bandwidth
systems. The microphone level at the lowest input level can be increased
by adjusting RV303 (MIC).