Sommerkamp TS-727G User manual

CITIZENS BAND TRANSCEIVER
INSTRUCTION MANUAL
MODEL1 TS-727G
FTZ APPRQVAL NQ.K9B/7Q
MODEL: TS-737

SQMMERKAMP ELECTRONIC
CH-BB15 LU ANO B X 130
SWITZERLAND
TEL. 091 Б8В543 TELEX:79314

CONTROL LOCATIONS:
MICROPHONE
PRESS-TO-TALK
BUTTON
ANTENNA
JACK
BRACKET
OFF/VOLUME
S METER qonTROL
TRANSMITTIN
LI HT
SQUELCH
CONTROL/ANL-SW
RECE1VIN
LI HT
PACKIN LIST:
Beside this manuał, the carton shall contain the following items:
1 Transceiver TS-727
1 Mounting bracket
2 Screw for Mounting bracket
1 Microphon hanger
1 Microphone
1 DC Cabie with Fuse
2

ENERAL DESCRIPTION
Your SOMMERKAMP TS-727 transceiver has been designed for continous heavy
duty mobile and base station application. It сап be operated with a microphone
and internal speaker or headset, speaker/ microphone combination, telephoneset
incorporating automatic voice operated transmit/receive switching, external sélective
i calling with automatic answerback and many more.
ENERAL:
The transceiver is designed to operate from 12 Volt DC powersupply as a
Г mobile station. Its straight forward 6 channel capability allows it to operate
on any combination of frequencies within 26.5 and 29.7 MHz by inserting the
corresponding Xtals and retuning the transceiver if requiredi The Xtals in the
transceiver are standard 27 MHz CB Xtals with plus or minus 455 KHz receiver
offset. No special synthesiser or IF Xtals are required.
RECEIVER SECTION
The receiver section is designed to receive amplitude modulated (AM/A3) signais
in the 26.965 to 27.275 MHz. (11 meter) citizens band. The unique combination
of low noise Field Effect Transistors (FET), single conversion, a combination
of mechanical ceramic, and L/C filters, fully automatic noise limiter and a hifi
quality speaker amplifier will give you exceptional réception quality in this
fine piece of equipment.
In addition, the above combination of the latest technology provides you with
a sensitivity and unwanted signal rejection and noise suppression available
previously only in space and military communication equipment.
The power supply of the receiver RF. IF and oscillator section is stabilized by an
extreme Sharp cut-off Zener diode to obtaîn the high sensitivity and unwanted signal
rejection. The fully automatic sériés gâte noise limiter, which virtuaily cuts off
the audio output during ignition noise puises, is defeatable to make even the
weakest signal audible which otherwise would be eut off by the threshold level of
the ANL switching diode.
The high squelch sensitivity is achieved by using a seperate squelch detector and
switching circuit with a carefully balanced hystérésis. The transformerless hifi
quality audio power amplifier will drive any load between 8 ohms and indefininite
such as internai speaker or external speaker/microphone or headset combinations
having the above impédances.
The meter indicates the field strength during réception of a signal.
3

TRANSMITTER & MODULATOR SECTION:
The transmitter section is désignée! for continous heavy duty transmission of
amplitude modulated (AM/A3) signais in the 26.965 to 27.275 MHz. (11 meter)
citizens band.
The transmitter consists of crystal controlled oscillator. The output of this
oscillator is foilowed by a tuned filter, and a highly efficient collector-modulated
dass C driver and power output stage, coupled by séries and pi-matching filters
to the antenna jack.
The modulator consists of an input audio filter, integrated pre-and power amplifier
and modulation transformer. This gives you the lowest possible modulation
distortion and up to 100% modulation. The input is designed for 500 to 10K ohm
dynamie microphone or 8 ohm speaker/microphone combination with a 1K ohm
resistor in sériés.
RECEIVE/TRANSM1T SWITCHIN :
The receive/transmit switching is done by a single pole, single throw switch in the
microphone and a combination of NPN and PNP switching transistors.
METER:
The combination meter provides you with the following functions:
During receive mode ...... it indicates the incoming signal strength.
During transmit mode-'-it indicates the output power.
MOBILE INSTALLATION
Mounting bracket and screws are supplied for mounting the transceiver underneath
the dashboard. Microphone hanger and screws are also supplied.
For electrical connection, first make sure that the transceiver is turned off.
Connect the red wire to the ACC terminal of the ignition switch or + terminal
of battery and ground the red and wihte or black wire to the chassis of the
vehicle. The black wire should be grounded as short as possible to minimize noise
interférence.
This transceiver is designed for use with the negative ground system.
4

50 OHM ANT.
Connect the antenna pług to the antenna jack with an SWR-Meter inserted into
the antenna cable.
Connect the microphone to the microphone jack.
Switch the transceiver ON.
The receiving, meter and the channei lamp shall light up.
Turn the Squelch control to min. (ANL OFF)
Turn the Volume control to max. until you hear a rushing sound from the speaker.
Switch the channelselector to CH 1.
Push the transmit button on the microphone and check with the SWR-Meter
immediately the SWR of your antenna. The SWR must be less than 1 to 2. Do
this within 3 seconds, because if the SWR is higher than 1 to 2 it is very likely
that the transmitting transistors will be damaged if you operate the transmitter
too long with a antenna having a too high SWR. Also read carefully the
recommendations on antennas.
If the SWR is less than 1 to 2 continue Checkout If it is more than 1 to 2
repair or replace your antenna.
Check that the meter needle is near the red mark during transmitting.
Talk into the microphone. The meter needle shall move a little.
Release the transmit button and switch the channei selector to channei 1,2 ectr,
until you receive a station.
Wait until this station stops to transmit and turn the Squelch control slowly to
max. until the background noise just disappears. When the station starts to
transmit again, you will hear this station, but you will not hear the background
noise during non transmitting periods.
5

The transceiver is ready to operate when it is instalied with an antenna properly
connected. Note that the communication range differs depending upon the environ
ment where the transceiver is operated. You may reach 30 or 40 kilometers
where no obstacle exists, but the range may be limited to 5 or 6 kilometers in
cities where many high buildings disturb the communication.
1) Turn the set on by switching the ON-OFF snap switch to ON and the channel
dial will be lighted. Turn the volume control clockwise to increase the audio
Sound. Note that the volume control knob is only for adjusting the audio
volume, not to increase the transmitting power.
2) Turn the squelch control clockwise until incoming noise is eliminated. Do not
turn it excessively as the sensitivity may be reduced.
3) Turn the squelch control counter-clockwise to switch off the ANL
(Automatic Noise Limiter)
4) Turn the channel selector knob to the desired channel.
5) For transmitting, press the button on the microphone and speak into it normally.
Release the button for receiving.
METER
The meter reading indicates the signal strength at receiving, and functions as an
output indicator at transmitting, and the meter pointer should be within the Red
zone under the normal conditions.
OPERATIN INSTRUCTIONS
6

MICROPHONE JACK
The 7-pin DIN standard accessory jack has the following internai connections:
1. Microphone input (Z 600-10K ohm) 5. Audio output (Z 8 ohm-10K ohm)
2. Transmit/Receive switching. 6. +12V for VOX unit etc.
3. Internai microphone output (Z 1K ohm) 7. round return for 1-6.
4. Internai speaker (Z 8 ohm)
Always operate the transceiver with the microphone plug inserted in the microphone
jack, or with the following external connections:
I. Microphone with VOX. 2. Headset or Telephoneset with PTT.
Microphone
3. External microphone 4. Headset or Telephoneset with VOX
Oc 2 4°
03 1«;
07 6o
□
4
O
Microphone
60CK 10k ohm
5. External microphone/speaker with PTT. 6. Internai connection
— 7

SCHEMATIC DIA RAM
ю т

1. Remove the unit from its mount, disconnect the power lead and antenna cable
at the rear of the unit.
2. Remove four screws of the side of the bottom-cabinet. (Speaker mounted side).
Carefully disassembled the cabinet. Remove speaker leads form the P. C. board.
3. The crystal socket are marked as 1.2. 3.4. 5. & 6.......for “ RECEIVE” (Receiving
crystals) and 1,2, 3,4, 5 & 6 for "TRANSMIT" (Transmitting crystals.)
(See Figure below)
4. Be careful when installing additional crystals, using too much pressure may
collapse the crystal case and ruin the crystal element contained therein.
5. When ail adjstments are madę, re-install the chassis in the cabinet and tight-
ening the cabinet screws. Connect the antenna wire and power lead in the same
manner as previously connected. Now the unit is ready for operation. Remember
to avoid operating the unit on channel position which hâve no crystals inserted.
Note: Frequency of the receiving crystals are lower frequency of the transmitting
channels.
Example: Tx: 27. 275 MHz.
Rx: 26. 820 MHz.
CRYSTAL INSTALLATION
10 -

PRINTED CIRCUIT BOARD PARTS LAYOUT
(SOLDERED SIDE)
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11

PARTS & WIRIN LAYOUT (COMPONENT SlDE)
12 -

PARTS LIST for TS-727
DESI NATION PARTS NAME PARTS N0.
MP 22 Chassis Frame 502033
MP 2 Chassis Frame Front 474035-2
MP 3 Cabinet Cover (Upper) 473008
MP 4 Cabinet Cover (Lower) 473009
MP 5 Mounting Bracket for Speaker 474038
MP 6 Mounting Bracket for Trimmer 474037
M il Microphone Hanger 484056
MP 1 2 Mounting Bracket . 474040
MP13 Screw for Mounting Bracket 474034
MP 14 Front Panel 504271
MP 15 Front Plate 504286
MP 23 Back Plate 494246
MP 17 Knob 474011
MP 18 Washer for Mounting Bracket 474033
MP 19 Lamp Lens (Red) M40024R
MP 20 Lamp Lens ( reen) M40024
MP 21 Washer for knob 484058
J1 Antenna Jack MRM/INCH
J2 Microphone Consent DIN Type 7P SJ-296
J4 Power Jack SJ-342
EP-1 Power Cord with Fuse Holder W-001
Fl Fuse 2A F-2A
Ml Meter D08A86R
SP Speaker 66P15-1
PL1/PL2 Pilot Lamp PL- 7371
SW1/SW2 Channel Selector Switch M26S - В
М/С Microphone Complété 12-31019
EP-503 Crystal Socket 12P XS-12P
ICI Integrated Circuit TA7205P
IC2 Integrated Circuit TA7200P
TRI FET 3SK40
TR2, 3, 4 Transistor 2SC1739 (P)
TR5, 6, 10 Transistor 2SC1739 (Q)
TR7 Transistor 2SC1741 (P)
TR8 Transistor 2SC1678
TR9 Transistor 2SC496 (O)
TR12 Transistor 2SC496 (Y)
TR11 Transistor 2SB435
— 13 —

PARTS LIST for TS-727
DESI NATION | PARTS NAME PARTS NO,
D14,15 Zener Diode WZ - 090
D9 Silicon Diode 1S1555
D l~ 8 Silicon Diode 1S 2473
D ll, 12, 13 Silicon Diode 1N4002
D6, 16 ermamium Diode 1N60
C81 Trimmer ECV-1ZW50P '
T10 Modulation Transformer TS-727 E
T9 Power Choke Transformer TC-1001
CF Ceramic Filter CFU-455H
L4, 6 RF Choke Coil 010-907
L5, 7, 8, 9 RF Choke Coil 005-903
L10 54 MHZ Trap Coil 005-901
VR1 Semi Variable Resistor 10K ohm SVR10K3
VR3 Semi Variable Resistor 50K ohm SVR50K3
VR2 Semi Variable Resistor 50K ohm SVR005K2
VR4 Semi Variable Resistor 50K ohm SVR50K2
Tl RX Antenna Tuning Coil 011-901
T2 RX RF Amp Output tuning Coil 5Z-345
T8 TX OSC Tuning Coil 5Z-345
T3 IFT. Coil (Yellow) 011-905
T4 IFT. Coil (White) 011-906
T5 IFT, Coil (Black) 011-907
11,2 TX Filter Coil 011-917
L3 TX RF Output Tuning Coil 134-901
T6 RX Local OSC, Tuning Coil 5Z-373
T7 TX Driver Tuning Coil 011-902
VR6-SW3 Squelch Control Variable Resistor VM11A-5M1112 10KB
VR5-SW2 Volume Control Variable Resistor VM11A-5M1112 50KA
_____ : ____________
■- 14 —

SPECIFICATION for TS-727 (TS-737)
Semiconductors 2 IC,12 transistor, 15 diode.
Transmitter System Triple stage, crystal controlled,
Coiiector modulation AM.
Frequency 6 channels on 27 MHz.
Frequency Tolérance Within 0.005% (-1 0 С to 5 0 t).
Output Power 0.5watts (3 watts).
Band Width 8 KHz (max).
Antenna Impédance 50 — 52 ohms.
Receiver System Single superheterodyne, crystal controlled.
Sensitivity 1//V or better for 500mW output,
10 dB signal to noise ratio.
Intermediate Frequency 455 KHz.
Receiver Seiectivity 30 dB down at 10 KHz.
Squelch Sensitivity 1 #V.
Audio Output Power 0.4 watts in 10% distortion.
Power Source 11 — 16 volts D. C. Neg. round.
Power Consumption (Tx) 0.18A(0,75A) at no modulation.
Power Comsumption (Rx) 0.1 A at no signal.
Microphone Dynamic type with press-talk switch.
Speaker Dynamic type 8 ohms V. C.
Size 121X35X 160
Weight 1.12 kg
Accessories Mounting bracket, Mounting hard wäre
Power Cord.
15