Salcom 11-38-0000 User Handbook

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).