Sommerkamp TS-340 DX User manual

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Model TS-340 DX
OWNERS MANUAL
40 + 40 CHANNEL MOBILE
AM/SSB TRANSCEIVER

GENERAL
Your new So erka p TS-340 DX is a Professional quality Citizens Band Transceiver designed to
operate on either AM, Lower Single Sideband (LSB) or Upper Single Sideband (USB). It has any
innovative engineering and user functïons. A ong the , a So erka p plus feature is an a plified
AGC circuit, built in to your TS-340. This expands the range of a nor al AGC circuit by any
ti es, and is usually found only in the ost expensive sets. Your a plified AGC will enable you to
hear clearly, even a very weak distant signal, and still allow you to hear a unit close by without
overload. The PLL (phase lock loop) frequency Synthesizer is the heart of the TS-340 DX's rock
steady frequency control. The PLL is self co pensating for frequency drift, keeping your TS-340 DX
on center channel, every channel. Careful reading of this instruction anuał before operation is
essential for proper operation and prévention of da age.
PACKING
This unit has been especially protected for ship ent. Open the carton carefully to avoid da age.
Exa ine the unit for any visible da age. If the transceiver has been da aged in ship ent, save the
box, and packing aterial, and notify the transportation co pany.
RECEIVER
Sensitivity of less than a 1/2 of a icrovolt on SSB and AM. A tuned RF stage pulls in even the
weakest signais.
A deluxe filter on SSB provides the highest degree of selectivity and rejection of unwanted adjacent
channel signais. Cera ic Filters for AM réception deliver over 70 db adjacent channel rejection.
Additional receiver features include: variable squelch, clarifier control, integrated circuit audio
prea plifier stage, etering auto atic noise eli inator.
TRANSMITTER
High efficiency is obtained through use of select co ponents and sophisticated engineering design.
An ALC circuit is e ployed in the SSB ode to provide axi u "Talk Power" without distortion.
The SSB signal is by use of an integrated circuit balanced odulator and PLL
Synthesizer, to keep you on center channel, every channel. Electronic switching is e ployed for
dependability.
POWER SUPPLY
Either Positive or Negative ground 12 Volts DC (13.8 VDC E!A) is built in.
1

OPERATION OF CONTROLS
PUSH-TO-TALK SWITCH tp) HIGH/LOW BAND SWITCH
N.B/ANL/OFF SWITCH
SWR/CAL/OFF .SWITCH
EXTERNAL SPEAKER JACK
Front View: Volu e Control
Squelch
Channel Selector
Clarifier
Channel Indicator
SWR/CAL
RF Gain
Mic Gain
Mode Switch
Model Light
High/Low Band Switch
NB/ANL Switch
CAL Switch
MOD/RF Meter Switch
CW Switch
CH 9 Priority
TX Light
MIC Jack
Rear View: Antenna Connector
DC Power Connector
Ext PA Speaker Jack
Key Jack for CW
Microphone: Push-To-Talk Bar
Vol-U-Mic
- 2 ~

FEATURES AND CONTROLS
VOLUME/POWER ON-OFP
This co bination contro! applies power to your TS-340 DX and adjusts the receiver volu e. The
switch should be turned clockwise fro the "O ff” position. You will hear an audible "click". The
channel LED and eter will light. To adjust the volu e continue advancing the control in clockwise
position.
VOL-U-MI KE
This auxiliary volu e control is an extension of the regulär front panel receiver volu e control. It
öfters great operating convenience by giving you instant volu e adjust ent right at your fingertips
while you are driving. As this is an extension control, the regulär front panel volu e ust be
advanced in order for the Vol-U-Mike to operate.
SQUELCH CONTROL
The squelch control is used to eli inate background noise when there are no signais present strong
enough to overco e the noise. To adjust the squelch control, select a channel where there is no
signai. Turn the volu e up to nor al listening levels. Rotate the squelch contro! clockwise until the
background noise disappears.
CHANNELSELECTOR
The channel selector switch is used to select the channel frequency. It auto atically adjusts both the
trans itter and receiver frequencies, and displays your sélection in bold L.E.D. (Light E itting
Diodes), nu erals.
MIC GAIN CONTROL
This control allows you to adjust icrophone sensitivity or power to co pensate for different
operating situations. Maxi u icrophone sensitivity or different operating situations. Maxi u
icrophone sensitivity or power is obtained at the full clockwise position and the control should be
set to this point for nor al operation and axi u range. Exa ples of how this control can help to
axi ize co unications effectiveness are as follows: When you are operating at extre ely close
proxi ity (within 100 yards or eters) of the other station, reducîng the icrophone gain ay help
to eli inate overload and distortion at the other station. When you are operating in an extre ely
noisy environ ent such as ay be found in the cab of certain large trucks, open sports cars, or
around noisy achinery, in order to avoid or reduce the a ount of noise that goes out with your
signal, you can reduce the icrophone gain and by speaking ore closely and loudly into the
icrophone, reduce the ratio of noise to voice.
- 3 -

RF GAIN CONTROL
This control allows you to adjust the basie sensitivity of the receiver section of the transceiver. It is
so ewhat like the icrophone gain control in that it allows you to co pensate for different or
varying operating conditions. Maxi u RF Gain or receiver sensitivity is obtained at the axi u
clock л/ise position of this control, and the control should be set to this point for nor al operation
and axi u range. For exa ple, when operating at close proxi ities to other strong signais, it ay
be helpful to reduce the RF Gain to avoid overload or distortion or interférence fro adjacent
channels.
MODE SWtTCH FOR LSB-USB-AM
AM trans ission is a plitude odulation of the radio frequency carrier with an audio signal (voice).
The co ponents of the trans itted signal include the carrier and its two sidebands, upper and lower.
For 100% odulation, each sideband contains one-fourth as uch power as the carrier. The
infor ation trans itted is in the sidebands.
USB trans ission is the trans ission of the upper sideband only of a single sideband signal. In single
sideband trans ission, the carrier and one sideband are re oved fro the trans itted signal. Thus,
only one sideband is trans itted.
LSB trans ission is the trans ission of the lower sideband, only. Rotate the ode selector switch to
the desired ode.
MODE FUNCTION LIGHT
The TS-340 DX has a dyna ie 3-way ode function light. In the upper sideband ode the light will
be green. The lower sideband ode will show red. The AM ode will show both red and green.
CLARIFIER
The clarifier is an electronic tuning circuit which allows you to shift the frequency of your receiver.
In SSB operation, even s all différences in frequencies between stations can cause poor réception. In
effect, the clarifier electrically fine tunes the station being received. In AM operation, this acts as a
fine tuning circuit.
TX INDICATOR
Your TS-340 DX is equipped with a LED (light e itting diode) trans it indicator lîght on the front
panel With the PTT switch on the ike depressed, the LED will light indicating you are in the
trans it ode.
HIGR/LOW BAND SWITCH
For ordinary 40 channel operation, set the switch position to ''Low''. In the "High" position, your
TS-340 DX opérâtes in the frequency range of 27.665 — 28.105MHz (High band 40 channels; 1
through 40).
- 4

S/RF-CAL-SWR METER FUNCTION SWITCH AND CALIBRATION
NOTE: THE TRANSCEIVER MUST BE IN THE AM MODE FOR THE SWR FUNCTION TO BE
USED.
In the botto position of the 3-position selector switch, the eter opérâtes nor ally as signal in, RF
output eter. In the center and top positions of this switch, the SWR (standing wave radio)
funcitons are activated.
To easure SWR, select an open or little used channel as close as possible to the center of the range
of channels you plan to operate on. If you plan to operate on ail channels 1 through 40, you should
select a channel between 17 and 23.
1. Set the function switch to Cal (calibrate).
2. Press the icrophone push-to-talk bar and adjust the front panel calibration control so the
eter pointer is at the SWR set position which is the s all red block at the right side of second
eter scale fro the botto . Release the press to talk bar.
3. Set the function switch to the top SWR position.
4. Press the icrophone push-to-talk bar and read the SWR easure ent on the botto eter
scale.
The SWR scale is calibrated at 1, 1.5, 2, and 3. If the eter pointer stops at 2, for exa ple, it would
be correct to say that the SWR is 2 to 1.
For a ore co plété understanding of SWR and how to reduce it, refer to the section appearing later
in this anuał titled "Understanding SWR".
CHANNEL 9 PRIORITY SWITCH
This switch provides instant channel change to e ergency Channel 9 without having to rotate the
channel selector.
NOTE: MOST CHANNEL 9 EMERGENCY MESSAGES ARE TRANSMITTED IN AM, SO IF
FOR EXAMPLE YOU ARE OPERATIŃG ON EITHER UPPER OR LOWER SIDEBAND
CHANNEL 16 AND YOU WANT ТО TRANSMIT OR RECEIVE AN EMERGENCY
MESSAGE ON CHANNEL 9 IT WILL BE ADVISABLE TO ROTATE THE MODE
SELECTOR TO THE AM POSITION IN ADDITION TO PUSHING THE CHANNEL 9
PRIORITY SWITCH.
"CW" SWITCH
For operating a Morse key device, set this switch to the"CW" position. Your TS-34Ó DX is provided
with a jack for the CW (Key Jack for CW) on the rear panel.
- 5 -

S/RF METER
The TS-340 DX is equipped with a large, easy-to-read co bination eter. In the receive position, the
eter reads the level of the inco ing signais. In the trans it position, it indicates relative power
output.
NOTE: 1. IN THE AM MODE, THE METER WILL READ POWER AT ALL TIMES WHEN THE
TRANSMIT BUTTON IS DEPRESSED. ON SSB, HOWEVER, IT WILL ONLY INDICATE
RF OUTPUT POWER WHEN YOU MODULATE THE SIGNAL.
2. IN THE SSB MODE, NO METER CAN FOLLOW THE RAPID VOICE PEAK POWER
ATTAINED. THEREFORE, WHILE THE TRANSMITTER IS DEVELOPING MUCH
MORE POWER THAN ON AM, THIS ADDITIONAL POWER WILL NOT BE FULLY
REFLECTED ON THE METER.
MODULATION/RF METER SWITCH
Allows either relative RF (Radio frequency) output or odulation output to be onitored while
trans itting.
NB/ANL (NOISE BLANKER/AUTOMATIC NOISE LIMITER) SWITCH
The TS-340 DX is equipped with both noise blanker and ANL circuits for axi u noise
suppression and elear réception.
DC CONNECTOR
This connector is used to supply power to your TS-340 DX. The plug-in feature allows easy re oval
for security purposes or for oving the transceiver to another vehicle.
KEY JACK FOR CW
For attaching optional CW (Morse key) device, si ply pług it into this jack.
EXTERNALSPEAKER JACK
You ay add any 8-16 oh external speaker. Si ply pług your accessory speaker into the jack.
NOTE: INSERTING THE 3.5MM PLUG WILL AUTOMATICALLY DISCONNECT THE IN
TERNALSPEAKER.
ANTENNA CONNECTOR
A standard SO-239 type connector is supplied for attaching either obile or base antennas.
MICROPHONE
The receiver and trans itter are controlled by the press-to-talk switch on the icrophone. To
trans it, si ply press in this switch. Release the switch to receive. When trans itting, hold the
icrophone 3 to 4 inches fro your outh and speak clearly at nor al voice levels. The TS-340 DX
uses a newly designed high level output icrophone. It delivers axi u talk power.
- 6 -

NEGATIVE CROUNDING
Almost all cars and most trucks are negative ground. Your TS-340 DX is designed to o erate on the
negative ground only. In the negative ground Systems, the minus (— ) ole of the battery is attached
to the car body, engine block, etc.
NEGATIVE GROUND HOOKUP
Attach the red (fused) wire to the fuse block ter inal or any convenient plus (+) lead. Devices
operated by the ignition key such as the radio, light, etc., are best since when you turn the ignition
off, the unit will be turned off. Attach the black lead to the car body via any convenient ethod.
NOTE: MANY NEWER CARS USE PLASTIC DASH PIECES. MAKE SURE THE SCREW OR
CONTACT YOU CHOOSE IS ATTACHED TO THE METAL FRAMEWORK OF THE
CAR.
GENERAL OPERATING INSTRUCTIONS
CAUTION: NEVER OPERATE THIS UNIT WITHOUT AN ADEQUATE ANTENNA SYSTEM OR
LOAD. ANTENNA SWR SHOULD NOT EXCEED 3:1. FAILURE TO FOLLOW THESE
R ECOMEN DATIONS COULD RESULT IN DAMAGE TO THE RE OUTPUT TRAN
SISTOR.
1. Make sure the proper connections have been adę for antenna syste , power cable, and
icrophone.
2. Set the Squelch Control fully counterclockwise.
3. Set the RF Gain fully clockwise. -
4. Set the Mîc Gain fully clockwise.
5. Set the Mode Switch to the desired ode.
6. Rotate the Volu e Control clockwise. You will hear an audible "click", and the eter and
channel lights will corne on. Continue rotating clockwise to desired listening level.
7. With no signal present, rotate the Squelch Control clockwise until the rushing noise disappears.
8. Set the Channel Selector to the desired channel.
9. To Trans it, si ply press and hold the push-to-talk bar on the icrophone a few inches fro
your outh and speak in a nor al tone of voice.
FAILURE TO MAKE THE PROPER CONNECTION COULD RESULT IN UNIT DAMAGE.
- 7 -

ANTENNA REQUIREMENT
This transceiver will operate with any standard 52 oh ground-plane, vertical, obile whip, long wire
or other CB antenna. A standard SO-239 type connector is provided on the back panel for use with
popular PL-259 antenna plug.
ANTENNA INSTALLATION
When the TS-340 DX is used as a base station, any Citizens Band bea , dipole, ground-plane or
vertical antenna ay be used. A ground-plane type will provide greater coverage, and since it is
essentially non-directional, it is ideal in base station to obile operation. Fro base station to base
station, or point to point operation, a directional bea will give greater distance even under the
adverse conditions.
MOBILE ANTENNAS
A vertical whip antenna is best suited for obile use. A non-directional antenna ust be used for
best results in any case. The base loaded whip antenna will nor ally provide effective
co unication. For greater range and ore reliable operation, a füll quarter wave-whip ay be used.
Either of these antennas use the etal car body as a ground plane, and the shield of the base lead as
well as the etal case of the transceiver should be grounded. A standard antenna connector (type
SO-239) is provided on the transceiver for easy connection to a standard PL-259 cable ter ination.
MOBILE INSTALLATION
A location in the car or truck should be chosen carefully for convenience of operation and
non-interference with nor al driving functions. Mounting ay be under the dash or instru ent panel
or any place a secure installation can be ade. An easy-release ounting bracket is supplied and
additional perforated straps or brackets ay be used as desired. The 12 Volt cable ay be connected
to any conven ent ter inal, but preferably to the ignition switch to prevent unauthorized persons
fro operation of your unit. With this ethod, the unit will only operate when your key is turned
on. Engine ignition interférence should not be a proble , and vehicles equipped with standard
broadcast radios should hâve enough suppression to eli inate ignition interférence. If interférence is
present, any skilled auto radio repair an should be able to eli inate it for you.
BASE STATION OPERATION
For base station use, a suitable regulated 2.5 AMP power supply is reco ended. When a power
supply is used, si ply connect the red (+) and black (— ) ter inais on the power supply of the (+)
and (— ) leads on your TS 340 DX
8 -

MOUNTING INSTRUCTIONS
WASHER x5 MOUNTING BRACKET
9 -

SPECIFICATIONS
GENERAL
1. Se iconductors
2. Frequency Range
3. Modes of Operation
4. Controls
5. Connectors and Jacks
6. Speaker
7. Microphone
8. Power Supply
9. Di ensions
10. Weight
RECEIVER
1. Sensitivity at S/N 10dB
2. Selectivity
3. AGC Figure of Range
4. Squelch Range
5. Audio Output Power
6. Distortion at input 100uV
7. Audio Frequency Response
8. Spurious Response
9. IF Frequency
10. Current Drain no audio
SSB TRANSMITTER
1. RF Output Power
2. Carrier Suppression
3. Unwanted Sideband Suppression
4. Plar onic Suppression
5. Current Drain
AM TRANSMUTER
1. RF Output Power
2. Modulation Capability
3. Har onie Suppression
4. Current Drain
22 Transistors, 2 FET, 10 IC's, 54 Diodes and 3 LED
Low Band 1 — 40 26.965 — 27.405MHz
High Band 1 — 40 27.665 — 28.105MHz
AM, Lower Sideband and Upper Sideband
Volu e Control with power on-off switch
Variable Squelch Control
Mike Gain Control.
RF Gain Control.
SWR/CAL Control.
Mode Selector Switches
Clarifier Control
Channel Selector Switch
Noise Blanker/ANL Switch.
Meter Select Switch.
CH-9 Priority Switch
CW Switch
High/Low Band Switch
Microphone Connector
Coaxial type Antenna Connector
Key Jack for CW.
External Speaker Jack
DC Power Jack
3-1/2 inches, 8 oh s
Dyna ic Microphone (500 Oh s)
13.8VDC
8" (W) x 1-1/8" (H) x 7-5/16" (D)
4 LBS 07 OZS
AM ......... 0,5uV SSB .......... 0.2uV
AM ......... 5KHZ SSB .......... 2.2KHZ
80dB
0.5uV - 1000uV
3 W atts
6%
300 -2200HZ
More than 45dB spurious signal is required to produce the
sa e a ount of audio output as the desired receive signal.
9.785MHZ
500 A
12 Watts PEP
More than 40dB
More than 50dB
More than 60dB
850 A
4 Watts
More than 80%
More than 60dB
1800 A
- 10 -

ALIGNMENT INSTRUCTIONS
1. RECEIVER
1) Set the Mode Switch to AM, Volu e Control at axi u, Squelch at ini u and Clarifier in
the center.
2) Set the SSG on Channel 40 and Channel Selector of the unit on Channel 40.
Then, connect the Power Supply and 8 oh s Du y Load to the transceiver unit.
3) Feed the signal fro the SSG and set the audio output for a peak reading by adjusting T-1, T-2,
T-3, and T-4.
In this case be sure that antenna input shouid be less than 1 pV at the AF standard output power.
Also, ake sure that the audio on the oscilloscope is a sine wave.
4) Set the antenna input at 1pV so that the antenna power ay be ore than 0.5 watt at the
axi u volu e of all channels.
5} Set the antenna input at 1,000pV so that the output power shouid be ore than 3.0 watts at
the axi u volu e.
6) Set the antenna input to 50,000mV and the low frequency output to 0.5 watt by volu e con
tro!. Then, decrease the antenna input until the low frequency output stays 10 dB lower. Be
sure that the antenna input then shouid be less than 5pV.
7) Set the antenna input to 100mV and the eter indication to 9 by VR-2.
8) Set the volu e control and squelch control at axi u , and set the tight squelch by VR3 so
that the output fro speaker is heard when the antenna input is increased upto 1,000д V.
9) Set the antenna input to 0.7pV and be sure that the low frequency output shouid be over 10 dB
ore when the odulation of the SSG is turned off at the nor al output.
10} Set the Mode Switch to USB, Volu e Control at axi u , Squelch at ini u and Clarifier
in the center. Tune off the odulation of the SSG and re ove the frequency by 1 KHz.
11) Make sure that the axi u sensitivity shouid be less than 1pV.
12) Make sure of AGC like with AM.
13) Set the antenna input to 0.2pV and keep the AF output to be over 10 dB lower when the
antenna input is turned off at the nor al output.
2. TRANSMITTER
1) Connection of test equip ent.
* Power supply at 13.8 VDC.
* Connect a Power eter, oscilloscope frequency counter, spectru analyzer and P-P RF volt
eter to the R F output connector.
* Connect an AF oscillator and AF volt eter to the icrophone connector.
2) Power adjust ent.
* Set the ode switch to AM.
* Adjust T-5, 8, 9, L-12, and L-3 for the axi u point.
* Adjust L-4 for 3.6W output,
* Adjust L-2 to increase 2nd har onie.
3) Frequency-Make sure every channel stays within ±800Hz.
4) Modulation Li iter Adjust ent.
* Put in 1KHz and 20 V signal fro AF oscillator and adjust VR7 for9Q% odulation
5) Modulation capability.
* Put in 1kHz signal by AF oscillator and get 90% odulation for the inus side. The plus side
shouid be over 80%.
6) SSB.
* Set the ode switch to USB.
* Put in two-tone signal of 1 KHz and 1.6KHz by two AF oscillators.
7) ALC align ent.
* Adjust the two-tone signal of AF oscillator for 3 W RF power output.
* Adjust VR-11 for 11 W PEP RF power output when the two-tone signal is increased by20dB.
8) Carrier suppression.
* Cut off the two-tone signal and ake sure the output level of the carrier is below —40 dB.
* Set the ode switch to LSB and do the sa e.
- 11 -

YOU AND YOUR ANTENNA
Three ain co ponents co prise a typical Citizensband installation. They are: your transceiver, an
antenna, and the coaxial cable which connects the antenna to the transceiver. It is i portant that ali .
three pièces are installed correctly to give the best possible range and reliable perfor ance. We hope
this pa phlet will be helpful for you to realize the axi u perfor ance of your installation.
ANTENNA
For several reasons, it is i possible to exactly PRE-TUNE an antenna at the factory.
A general range of tuning is done which ay suffice, but for best perfor ance, an antenna should be
turned after it is installed.
Most antennas hâve so e for of tuning capabilîty. Usually, this involves the whip section sliding
into a coil, spring, or etal section. This allows the antenna to be adjusted to the exact frequency
desired. We cannot stress enough the i portance of tuning your antenna. The easure of an antenna's
perfor ance is its "SWR" (standing wave ratio).
"COAX"CABLE
Coax cable is used in ail Citizensband installations. This cable transfers the power fro your
transceiver to the antenna. The output of your transceiver is 50-52 oh s. Your antenna is designed
to be 50-52 oh s. For this reason, RG58/U or RG8/U cable is used because it also is 52 oh s and
atches the antenna to the unit. The frequency of the antenna is very i portant in this area because
a is-tuned antenna can disrupt the syste balance. If this balance is disrupted, standing waves are
generated on the coaxial cable, which results in a loss of power in your transceiver.
UNDERSTANDING SWR (Standing Wave Ratio)
In theory, your transceiver has a 50 oh output and your antenna is 50 oh s. If a 50 oh cable
(such as RG58/U or RG8/U) is used, ail the power fro your transceiver will be trans itted via the
coaxial cable and radiated by the antenna. Underthese conditions, the SWR (standing wave ratio) of
your antenna syste would be 1:1. In practice, the antenna ust be 50 oh s and tuned to the exact
channel. This condition seldo exists and standing waves are set up on the cable. This SWR robs you
of power and likewise range. While 1:1 is not always possible to attain, you should tune your antenna
syste so the SWR does not exceed 1.5 to 1 or at axi u 2 to 1. Неге are so e exa ples of the
power losses for various SWR ratios:
- 12 -

SWR Power Lösses
1:1 = 0
1.3:1 =2%
1.5:1 =3%
1.7:1 =6%
2:1 =11%
3:1 = 25%
4:1 =38%
5:1 =48%
6:1 =55%
10:1 =70%
TUNING VOUR ANTENNA
For opti u perfor ance, an SWR eter should be used to tune the antenna. However, since this
eter ay cost fro §15.00 to §30.00, not everyone ay want to invest in its purchase. If possible,
borrow one. If you are unable to borrow one, the RF output eter on your transceiver can be used
as a GUI DE to antenna turning. While it is not 100% accurate, it is generally better than no tuning at
all. Always tune your antenna in an open area. Wires, etal and copper tubing if nearby can effect
the tuning. Never tune an antenna inside a garage, under a etal car port, next to a etal truck, etc.
A. USING YOUR TRANSCEIVER OUTPUT METER AS A TUNING GUIDE
After installing your antenna syste , place the whîp halfway into its réceptacle and turn your
transceiver to Channel 20. Depress the switch on your transceiver icrophone, and ake note
of the reading on your RF output eter. Loosen the adjustable whip section and ove it 1/8 to
1/4 inch down. Again depress the trans it switch, if the reading is the sa e or lower continue
oving the whip down 1/4 inch at a ti e until the LOWEST reading is obtained on your
transceiver RF eter. If the reading was higher, ove the whip up 1/4 to 1/2 inch the first ti e
and 1/8 to 1/4 inch thereafter until the LOWEST reading is obtained on the RF eter. That's
right... .
THE LOWEST READING. Your RF output eter is a voltage sensing device. It is installed in
the RF output circuit and senses the voltage near the antenna ter inal. In a perfectly tuned
syste all of the voltage is transferred fro the output transistor and passed to the antenna. As
an exa ple, let's use the figure 10. If there is SWR on the line, the forward voltage is 10 and a
reverse voltage appears (let's say it's 2). The eter circuit now sees 20 and shows a higher
reading. You can see that because of the way ost RF output eters work, the LOWER your
RF output eter reads the better your antenna is tuned. Of course, if the eter reads less than
1/2 scalę, it ay indicate a proble in your set and should be checked. Si ilarly, an extre ely
high reading ay indicate a proble in your antenna. An RF output eter can tell you
uch . . . especially if you know how to use it.
B. TUNING YOUR ANTENNA WITH AN SWR METER
Using an SWR eter is the ost accurate way to tune an antenna.
Connect the SWR eter as close as possible to the back of the transceiver. Use a double ale
connector or a very short piece of RG58/U with connectors on each end.
Place the adjustable whip halfway into its réceptacle. Set your transceiver to Channel 20.
Measure the SWR following instructions supplied with the eter. After the first easure ent,
ove the whîp down 1/8 to 1/4 inch and repeat ALL the steps again. If the SWR is lower,
- 13

continue the process oving the whip down 1/8 ю 1/4 inet i ai a ti e u ri ti i the lowest reading is
obtained. If the SWR is higher, raise the whip 1/4 to 1/2 irich the first ti e and 1/8 to 1/4 inch
thereafter until the lowest SWR is obtained. Note, if the reading continues falling but you hâve
reached farthese point down that you can go with the whip, the whip ay be too long. To
verify this, put the Channel Dial to Channel 1 and easure Lite SWR, Next, put the channel dial
to Channel 40 and easure the SWR. IF THE SWR WAS LOWEST ON CHANNEL 1 AND
HIGHEST ON 40 THE WHIP SECTION IS ТОО LONG. Carefully eut 1/4 to 3/8 inch fro the
whip section and re- easure Channels 1, 20, and 40. If the SWR is still lowest on Channel 1
continue tri ing the whip by re oving 1/8 to 1/4 inch at a ti e until the lowest SWR is
obtained on Channel 20. DO NOT G ET OVERANXIOUS. YOU CANNOT REPLACE A
SECTION ONCE IT IS CUT OFF. If you exceed slightly the best tuning for Channel 20, the
whip ay be raised 1/8 to 1/4 inch at a ti e to obtain the best SWR on Channel 20.
WARNING: DO NOT CUT THE WHIP USING THE "POWER OUTPUT METER TUNING
METHOD". YOU MUST USE AN SWR METER ТО ACCURATELY DETERMINE THE SWR.
Every six onths or so, re-check the SWR. Car washes, rod gri e, and Che icals can eftect the
echanical connections of an antenna and corrode the . This corrosion can cause poor
electircal connections and lead to high SWR. The correction of this proble is usually
acco plished by cleaning of the etal connection parts with a wire b rush.
HELPFUL HINTS
1. High SWR robs you of range and puts a strain on your output transistor.
ALWAYS TUNE A NEW ANTENNA.
2. Never tune your antenna in a closed area (garage, under a etal car port, etc.) as
ay resuit.
3. MAKE SURE ALL MECHANICAL CONNECTIONS ARE TIGHT.
4. DON'T SMASH OR SHARPLY BEND THE COAX CALBE - it should re ain generally round
to do its job properly.
5. TIGHTEN YOUR PL-259 CONNECTOR OCCASIONALLY - road vibration has a tendency to
loosen it which can cause output transistor'Proble s.
6. PERIODICALY (every 6 onths) re-check your SWR. Corrosion and road gri e ay rob you
of perfor ance.
7. PERIODICALLY check your coax cable for wear. A broken or loose wire could cause RF
output transistor failure.
This infor ation was produced to help you understand the installation and aintenance of your
antenna and cable feed syste . Many field proble s hâve been traced to Proble s such as the above.
They can lead to eventual failure of the RF output transistor in your transceiver. Careful installation
and aintenance can prevent these proble s.
... 14 -

ACCESSORY JACK
The 7-pin DIN standard accessory jack has the following connections:
1. Internal speaker (Z 8 Oh )
2. Audio detector output
3. Audio output (Z 8 Oh -32 Oh )
4. Microphone input (Z 600-10 К Oh )
5. External Vol. Control
6. +12 Volt
7. transmit/Teceive Switching
Case ground Alv.-ays operate f.he transceiver willi the shortening plug inserted in the accessory jack,
or with the following extcnal connections:
I. Headset or Telephoneset with PTT.
2. External icrophone 3. Headset or Telephoneset with VOX.
O 5 2 4
0 3
О
Microphone
600 lOK oh
4. External icrophone/speaker with PTT.
5. PARROT 76
CODF SELE CÏO R SW
15 -

CIRCUIT DIAGRAM