TR160
DATA TRANSCEIVER
USER'S
HANDBOOK
SEA AIR & LAND COMMUNICATIONS LTD, 120 ST. ASAPH STREET, PO BOX 22-621, CHRISTCHURCH, NZ
SALCOM TR160 DATA TRANSCEIVER 10-95-0000 USER'S HANDBOOK - ISSUE 10950000UA
Sea Air & Land Communications Ltd. Page 2
SALCOM TR160
DATA TRANSCEIVER
DESCRIPTION
The TR160 is a VHF 500mW narrow band FM transmitter and receiver with
receive/transmit change over circuitry including aerial switching. It is intended for use
as an outstation telemetry transceiver for the VHF Telemetry Band C on 160MHz with
25kHz channel spacing.
TRANSMITTER
The transmitter consists of a 50MHz Colpitts oscillator incorporating a varicap diode
for direct FM modulation. The oscillator output circuitry, L103 and L104 are tuned to
3 times the oscillator frequency and couple to the base of the amplifier Q103. Q104
and Q105 further amplify the 160MHz signal and the 500mW output is fed via a two
stage low pass filter to the aerial connection.
Audio from Tx Audio 1 (Pin 3, S1) is attenuated by the preset control R122v and
amplified by IC101 which also tailors the frequency response to the required
bandpass. The stabilised output voltage and the superimposed modulation are
applied to D102, the modulator diode. Tx Audio 2 (Pin 13, S1) provides a high
sensitivity audio input. IC102 amplifies and compresses the signal to give constant
transmitter deviation with inputs ranging from 5mV to 5V RMS. R123v provides
adjustment for the transmitter deviation.
Transmission is initiated by pulling PTT low, turning Q10 (transmitter supply) on and
Q12 (receiver supply) off.
TRANSMITTER SPECIFICATIONS
Frequency Band .... 150-165MHz
Type of Emission .... FM, 25kHz chan spacing
Power Output .... 500mW max. @ 13.5V
Spurious Emissions .... -26dBm max.
Power Consumption .... Transmit: 13.5V, 190mA
Modulation .... Deviation: ±4kHz max
Sensitivity: Tx1 50mV=±4kHz dev
Tx2 5mV-5V=±4kHz dev
Passband: 100Hz-3kHz
Crystal .... Fxtal = Ftx ¸ 3
Spec: HyQ GG13S, Rakon DEP00
RECEIVER
Signal passes via an input bandpass filter to Q1 RF amplifier, then via a 3 stage
bandpass filter to the base of the mixer.
The Colpitts series mode oscillator triples in its collector circuit, is filtered by a tuned
circuit and fed as injection to the base of the mixer Q2 along with the rf signal.
SALCOM TR160 DATA TRANSCEIVER 10-95-0000 USER'S HANDBOOK - ISSUE 10950000UA
Sea Air & Land Communications Ltd. Page 3 Sea Air & Land Communications Ltd. Page 4
Mixer output passes through a 10.7MHz crystal filter to a 2 stage discrete amplifier 600O OPTION
and then to the input of IC1. The 10.7MHz signal is converted to .455MHz in an
internal mixer which uses a 11.155MHz crystal X2 for its injection.
Signal emerges, is filtered by CF1 .455MHz, and further amplified within IC1 before
being detected by quad coil L7.
Audio output from pin 9 IC1 is fed via R41v to an internal op amp configured as a
noise amplifier, amplifying frequencies above 3kHz and then rectified and amplified
by Q7.
The dc voltage at Q7 collector which changes as the RF signal increases, is applied
to the internal squelch dc amplifier with hysteresis, the output of which drives
squelch switch Q6.
Pin 13, IC1 goes high with signal, turning Q8 and D3 on producing a low on the
BUSY output S1, pin 7. Reverse the busy output phase by cutting the pcb link at
"Busy" and linking to "+".
Audio output from pin 9 IC1 also passes via an LP filter R40, C43, level control
R40V, squelch switch Q6, through audio amp IC3, and to pin 2 on S1 as a 600O
unbalanced output. Link the pads at "Audio" for an 8O output. Test the audio output
from the PCB stake at "Audio". IC2 regulates the receiver voltage to 8V.
RECEIVER SPECIFICATIONS
Frequency Bands .... 150-165MHz
Type .... FM dual conversion 10.7/.455MHz
Sensitivity .... -117dBm min for 12dB SINAD.
Selectivity .... 65dB min., ±25kHz
Spurious Responses .... 65dB min.
Blocking .... 84dB min @ ± 200kHz
Intermodulation .... 50dB min 2 generator test
IF Bandwidth .... ± 7.5kHz
Squelch .... Adj. to unmute 6dB - 20dB sinad
Audio Outputs Test O/P .... 500mW max, 8O monitor O/P.
Pin 2 S1 .... 6V p-p max, 600O unbalanced
500mW / 8O with link.
Pins 11,12 .... 600O balanced option 250Hz-4kHz
Power Requirements .... 13.5V, 25mA squelched.
200mA full audio / 8O.
Crystal .... Fxtal = (Frec - 10.7) ¸ 3
Xtal type = TE1, HyQ GG05S
Rakon DDD00
T/R CHANGEOVER
On receive Q12 is turned on providing supply to the receiver and when PTT is pulled
low, Q10 and Q11 turn on. Q11 starves Q12 depriving the receiver of supply while
Q10 supplies the transmitter with power. On receive D1 and D101 are turned off,
allowing aerial input to the receiver while on transmit D1 and D101 are on, allowing
transmitter power to the aerial.
SALCOM TR160 DATA TRANSCEIVER 10-95-0000 USER'S HANDBOOK - ISSUE 10950000UA
600 Ohm In/Out Transformer. Provision has been made on the PCB for a
transformer which is obtainable from Salcom either as a retrofit or can be included
in new units if requested. Join pins 2 and 3 on S1 and use pins 11 and 12 as the 600
Ohm Input/Output port.
TRANSMITTER TUNING INSTRUCTIONS
1. Install the correct crystal.
2. Connect the transmitter via a coax lead to a 50O load
3. Connect the unit to a +13.5V power supply
4. Liven up the transmitter by grounding PTT connection, pin 5 on S1
5. Using an EVM with a 100KO isolation resistor on the probe tip, check Q101
base and emitter voltage to ensure oscillation. The voltage difference should
be in the region of 0.4V
6. With the probe on Q103 emitter tune L103 & L104 for a peak
7. With the probe on Q104 base tune for a peak negative voltage
8. With the probe on Q105 base tune L106 for a peak negative voltage
9. Tune L108 for maximum power which should be 400-500mW. If not, adjust
R115 for the desired result, a lower value will increase the power output
10. Adjust L101 to give the correct transmitter frequency
11. Connect an audio generator to Tx Audio (pin 3, S1) and adjust to give 100mV
RMS, 1000Hz at its output. Adjust R122v to give ±4kHz deviation and view the
demodulated output on an oscilloscope. There should be no appreciable
distortion although a small amount of second harmonic will be generated and
is tolerable.
TYPICAL VOLTAGES
Not oscillating Oscillating
Q101 Emitter 1.75V 1.9V
Base 2.5V 2.1V
Q102 Emitter 10.75V 8.3V
Base 10.0V 9.7V
Q103 Emitter 3.0V 2.95V (peaks)
Base 3.7V 3.55V
Q104 Base 0V -0.1V (dips)
Q105 Base 0V -0.2V (dips)
Q10 Emitter 12.7V
Base 12.0V
Collector 12.6V
Input Voltage 13.5V
IC102 Pins 1, 2 & 3 6.5V
RECEIVER TUNING INSTRUCTIONS
1. Install the correct crystal. F.xtal = (Fsignal - 10.7) ÷ 3.
2. Rotate R41v fully anticlockwise to disable the squelch.
3. With the unit connected to a 8O speaker/sinad meter and a signal generator
tuned to the receiver frequency, turn on the supply voltage.
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