Kenwood TR-851A User manual

GOO/ANADI
430MHz ALL MODE TRANSCEIVER
TR-851A
TR-851E
144MHz ALL MODE TRANSCEIVER
TR-751A
TR-751E
INSTRUCTION MANUAL
KENWOOD CORPORATION
CPRINTEG IN JAPAN 850-8111-00 (K, M, T, WXT)
10987654321 2

Thank you for purchasing our latest transceiver. This
unit has been carefully engineered and manufac-
tured to rigid quality standards, and should give you
satisfactory and dependable operation for many
years.
IMPORTANT: $$
Please read this instruction manual carefully before
placing your transceiver in service.
The following explicit definitions apply in this
manual:
Note: If disregarded, inconvenience only, no risk
of equipment damage or personal injury.
Caution: Equipment damage may occur, but not
personal injury.
This Instruction Manual covers the TR-851A/
851€/751A/751E.
When there are differences in operation
separate instructions will be given for each
model. Illustrations show the TR-751A.
CONTENTS
1. BEFORE OPERATION. ..............::ssseeesseeeeeeeees 4
2. SPECIFICATIONS AND ACCESSORIES ........... 5
2-1, SPECIFICATIONS ......... ce eeeeeeeeeeeeeeeeeeee 5
2-2. ACCESSORIES .............000000 . 6
3. INSTALLATION AND CONNECTION.. - 7
“1. INSTALLATION............ccceeeee .7
3-2. CONNECTION . 8
4. OPERATION ......ccccccecssseesseesseecssesssesess 1.10
4-1. CONTROLS AND THEIR FUNCTIONS ..
4-2. RECEPTION........
4-3. TRANSMISSION . 18
4-4, MEMORY........... +18
4-5. SCAN 0... eeccceeeeeeeceeeseneeeeeeeeeeeseaeeeeeees 21
4-6. REPEATER ............cccceecessecceeeceteeeeeeseees 22
4-7. DCL (Digital Channel Link) SYSTEM.. we 2S
4-8. VOICE SYNTHESIZER.............0004 see
4-9. MICROPHONE UP/DWN SWITCH..
5. MAINTENANCE AND ADJUSTMENT... es
5-1. GENERAL INFORMATION ..............ceeeeeee 33
5-2. SERVICE...........scccssssasvescesseceeneneeessueooren
5-3. CLEANING
5-4. IN CASE OF DIFFICULTY
5-5. MICROPROCESSOR BACK-UP LITHIUM
BATTERY REPLACEMENT. ...........ccceeeeesees 34
5-6. ORDERING SPARE PARTS. a
5-7. ADJUSTMENTS..........ccccccceesseeesseseeeeenees
7-1, TU-7 TONE UNIT
7-3. TU- 7 TONE UNIT AND MU-1 MODEM UNIT... 43
7-4. VS-1 VOICE SYNTHESIZER UNIT.............. 43
7-5. OTHER ACCESSORIES ............ 144
8. REFERENCE..............

1. BEFORE OPERATION
Safety precautions
Never remove the case unless specified in this Instruction
Manual. If the internal parts are touched, accidently, a serious
electric shock might occur.
Never touch internal parts.
If a meta! object, such as a hait pin or a needle, comes into
contact with the power socket on the rear panel, a dangerous
electric shock may result. For families with children, never
permit children to put anything, especially metal, inside this
unit.
Touching the power plug when your hands are wet may result
in a serious electric shock
wal
ly . v
JOD SA Never touch with wet hands.
o6
Never pull, bend or extend the power cord. This could
damage the power cord, resulting in a broken cord or short:
circuit,
SN
™ Always grasp the piug.
In case of abnormal smell
If an abnormal smelt or smoke is detected, immediately turn
the power OFF and pull out the power cord. Contact your
dealer or nearest Service Station.
Notes on installation
Do not place the unit m a place which is exposed to direct
sunlight, neat a heating appliance, etc.
Do not store or use the unitin a dusty location or in a moist at-
mosphere. Select a ocation where a:r is well ventilated
To maintain good ventilation, do not put records or a
tablecloth on the unt. Place the unit at feast 10 cm away
from the walls
The unit may not functon properly if used at extremely low,
or freezing temperatures
Cleaning
Do not use volatde solvents such as atcoho!, paint thinner,
gasoline, benzine, etc. to clean the cabinet. Use a silicone
cloth ar a clean dry cloth
Sibcone cloth Thinner Benzine

2. SPECIFICATIONS AND ACCESSORIES
2-1. SPECIFICATIONS
Specification Cia: cee ele eee ; Teele | TR 731A TRS TE i
“Frequency range 430 to 440 MHz | 14410148 MHz | 144 to 146 MHz
cae eae ~~ USB/LSB (J3E), CW (ATA), FM (F3E, F2D
for the contro! signal of the DCL system) i
Antenna impedance 50 ohms i
Power requirement 13.8 VDC +15% !
_ | Grounding Negative
5 ! | Receive mode with no in- OBA
§ | Current drain put signal '
fee | Transmit mode {Max.) { 7.5A | 6A
Frequency stability (20°C to +60°C) | aleiobal | Better than +15x 10°
| Operating temperature \ —20°C to + 60°C (—4°F to + 140°F)
|_ Dimensions (W x H x D) (Projections included) | 180 x 63 x 233 mm | 180 x 63x 213 mm
Weight : , 2.5 kg (5.5 Ibs) | 2.2 kg {4.8 Ibs)
. [HI | 25 W
Output power gesa eS Fists :
i | LOW | 5 W (Adjustable up to out 25 W)
: | USB/LSB i Balanced modulation
5 | modulation i FM : Reactance modulation
= | Spurious radiation Less than —60 dB
& | Cartier suppression (SSB) ' More than 40 dB
Br idab i
& | Unwanted sideband suppression (SSB) More than 40 dB .
‘ Maximum frequency deviation (FM) +5 kHz
_Audio distortion (FM, at 60% modulation) == Less than 3% (300 to 3000 Hz) 7
_ Microphone impedance 7 500 to 600 ohms _|
: ' USB/LSB/CW polar anlairta' a Single conversion superheterodyne
ircuit I ek Peay Prag Spe
¥ | FM sensed ve. Double conversion superheterodyne
ee. - 41.415 MHz |
Intermediate frequency 10.695 MHz2/ ' 10.695 MHz/455 kHz (FM only)
; 455 kHz (FMonly) ) | a ie
5 | Sensitivity | 110.08 SAIN) Less than 0.11 V i Less than 0.13 pV
2 F : _ | FM (12 dB SINAD) Less than 0.18 «V | Less than 0.2 pV
é LORELEI Ook ce : GLE thee 2 2 aHe
, 60 dB Less than 4.8 kHz
Selectivity Mm dB Me than 12 kHz ;
Dek, | es, Clee -60d8 - Less than 24 kHz
Spurious response — Better than 60 dB | Better than 70 dB (Except fd-IF/2)
RIT variable range More than + 1.2 kHz
. Squelch sensitivity i ___Less than 0.1 pV
| Output | More than 2 W across 8 ohms load (5% distortion)
| External speaker impedance ' 8 ohms
. Code NRZ equal-length code
| Modulation _MSK modulation
§ Frequency deviation : +3.5 kHz (Reference)
; s Mark frequency and deviation | 1200 Hz, +2x 10+
o | Space frequency and deviation ar : 1800 Hz, +2x 10% :
| Code transmission speed and deviation ‘| 1200 bits/second, +2x 10
Notes:
1. Circuit and ratings are subject to change without 2. * Recommended duty cycle
notice due to advancements in technology.
1 minute : Transmission
3 minutes: Reception

2-2. ACCESSORIES
Unpack your transceiver carefully and confirm that it is supplied with the following accessories.
Dynamic microphone (TR-751A U.S.A. version only) .........
Dynamic microphone (Except TR-751A U.S.A. version) ..
Hook (TR-851A U.S.A. version only) ..........ccceceeseeeeeree .
Hook (TR-751A U.S.A, version Only) ...........c.seceecssceenereesenreceeceeneeensteeeeenen
Tapping screw (TR-851A U.S.A. version Only).........:ssseeeeeseeeereeeeeeteseeeeaneres (NO9-0633-05) ....
Tapping screw (TR-751A U.S.A. version OMly)...........:--ssseeeeeeeseeeeeereeeeseeenes (N46-3010-46)
Mobile mounting kit
Bracket.........ccseseeee ste sdehdaecceeuasananeaseee david nes svovesecssteeeewetes {A13-0668-04)
Bracket ass’y (Right) ...........ccccsssceeccereesersreneeseeaeeesssnecerceeseesseensanseesees {A13-0666-12)
Bracket ass’y (Left) .. .. {A13-0667-12)....
Cushion .........cceeeeee ... (G13-0823-04) ....
Allen bolt (Black)... ...(N99-0304-04)
Hex socket screw . ...(NO9-0008-04)
Flange nut........... ...(N14-0510-04) ....
Flat washer (Black)...........ccccsessencerseeeeeeeereeeeesesoes ...(N15-1040-45) ....
Flat WaSHE?, ..0...ccccscvccsssasecevcnrsecesccnscnccsnceresonssess ...(N15-1060-46) ....
Spring washer... (N16-0060-46)
Tapping screw .. .. (NO9-0632-05)....
HO WITCH cs cissivissvadnvinntewessnaadoaee to ¥en ccnnaneadaveydeadnak aUecbines te Rdencenboore ver {(W01-0401-05) ... 6
DC power Cable ...........ccececcsseeceeseeeeeeeeeseeeeeeecerseseeseeeeeenseeeeeeaeeeeeeeenes {E30-2053-05).. lea
A-DIM PIUG.........eeeccsecnseceeeeteeeeee ...(EO9-0471-05).. 1 ea.
Spare fuse (8 A) for TR-851A/851E.. ... (FO5-8021-05).. weed ea.
Spare fuse (7 A) for TR-751A/751E.. we (FO5-7025-05)......ccceeeeeeee 1 ea.
FOOt vcs sisssccevevesseaversbescttectcuscesvecanctsacdobeiscsestadseedecdesssilecasessesecaceseeediues (JO2-0439-05)..........cceeeee 4 ea.
INStrUction
MANUA
...........cccecceeeceeeeeeeessnaeeesneeeeueeseenecennecsserersaeeeseneeneeeees
(B50-8111-O0)
.........:.000
1
copy
After unpacking
Shipping container:
Save
the
boxes
and
packing
in
the
event
your
unit
needs
to
be
transported
for
remote
operation,
maintenance,
or
service.

3. INSTALLATION AND CONNECTION
3-1. INSTALLATION
3-1-1. Precautions
1. Avoid direct sunlight, and select a dry, well ven-
tilated location.
2. Since the heat sink is on the rear panel, avoid
placing the equipment with the bottom and rear
sides close to a wall or desk.
3. When installing the equipment in an automobile,
ensure adequate ventilation. Install the equip-
ment in a location where the rear does not make
direct contact with the seat, and is not directly
exposed to vibration.
4. Avoid installing the equipment in front of the car
heater air outlet.
3-1-2. Power supply
The standard operating voltage of these transceivers
is 13.8 V. The current is 7.5 A with the TR-
851A/851E and 6 A with the TR-751A/751E. Do
not use a power supply (either fixed or mobile) that
provides over 16 V with the POWER switch of the
transceiver turned off.
Operation under such conditions will void the war-
ranty. Also, do not use a power supply that does not
supply at least 12 V in transmit or receive. Use of
such supply may cause the performance of the
transceiver to suffer.
3-1-3. Foot installation
Attach the feet (4 pcs.) using the following pro-
cedures,
1. Place the radio with the bottom up.
2. Place each foot on the bottom cover so that the
hole in the feet line up with the holes in the bot-
tom cover.
3. Insert a rivet with pin into the hole of each foot.
(Make sure the pin is not inserted too far or the
tivet will not go in.)
4. Push the pin down securely to complete the in-
stallation.
fuvet
3-1-4. Mounting bracket
A. Secure the transceiver under the dashboard us-
ing the supplied mounting bracket. Install the
bracket as shown below. Do not install
backwards.
Nut
bal
ot
32
_—~
—_——_
Af.
Mounting
Ga
Prat
washer
aT
tat
washer
bracket
4!
Bolt
Spring
rye
7
washer
;
Tapping
screw
3
:
a
Moun
bracket
B. Installing the transceiver
Note:
Make sure that the transceiver will not slip out of
place while operating the vehicle.
Follow the steps below:
1. Lift the lever.
2. Carefully slide the transceiver into the mounting
bracket.
Step 2
3. The angle of the bracket may be adjusted to any
of 5 possible viewing angles by loosening the 4
allen bolts at the top of the bracket using the hex
wrench provided.
After the desired angle has been selected tighten
the 4 bolts.
Step 6
4. Press the lever down to secure the transceiver.
5. By installing a lock thru the keyhole on the side
of the mounting bracket, the lever can be locked
and the transceiver secured.

3-2. CONNECTION
3-2-1. Precautions
1. Before connecting and disconnecting the power
connector, be sure to turn off the power swit-
ches of the transceiver and the DC power supp-
ly.
3-2-2. Fixed station
AC
3-2-3. Mobile SP-50 of SP-40
Transceiver
> To battery
Accessories OC cate
A. Battery connection
Connect the supplied power cable with fuse directly
to the battery terminals. Connecting to the cigarette
lighter socket can cause a poor connection, and ex-
cessive voltage drop.
Caution:
1. When connecting or disconnecting the power
cable to or from the power connector, be sure
that the power switch is always in the ‘‘OFF’’
position.
2. Disconnect the transceiver before jump-starting
or before charging the battery.
2. Observe polarity of the cable. The transceiver
operates on 13.8 VDC, negative ground. Bat-
tery polarity must be correct. The power cable is
color coded:
Red —
Black ~—
+ (Positive) polarity
— {Negative} polarity
Transceiver
Antenna
—_)
Transceiver
as eee
a :
eO. @,
EL AS
“7
ae
.
Rubber grommet
To battery

i When installing the transceiver in a vehicle, consider ease of operation and safety when selecting the installa-
tion location.
Make sure the positive (+) and negative (—)} !ead polarity are correct when wiring to the battery.
Engine compartment <——— f ——> Passenger companment
Select the location
where the power cable
iS protected from heat.
moisture of abrasion
secure the cable.
Chassis or fire watl
To the transceiver
Make sure the cable
Goes mot duectly con-
tact the edge of the hole
by using 3 grommet
Notes: --
1. Before installing the power cable, be sure to
remove the negative lead from the battery for
safety.
2. After installation and wiring, be sure to double
check for correct installation before reconnec-
ting the negative lead to the battery terminal.
3. If the fuse opens, be sure to check that each con-
ductor has not been damaged by short-
circuiting, etc.
Then replace with a new fuse of the same rating.
4. After completing the wiring, wrap the fuse
holder with tape to protect against moisture.
5. Do not remove the fuse even if the power cable
is too long.
@ If the wiring hole in the fire wall or chassis is too
small, disassemble the fuse holder to thread the
wire through the hole.
From passenger
compartment
Oy
Thread Iske this.
=
B. Ignition noise
This transceiver is designed to suppress ignition
noise; however, if excessive noise is present, it may
be necessary to use suppressor spark plugs (with
resistors), or an external noise filter such as the PG-
3B.
Note: -
20 A fuse is used in negative (ground) line for addi-
tional protection.
3-2-4. Antenna
The antenna impedance is 50 ohms, do not use an
antenna with other impedance ratings. Securely at-
tach the antenna.
3-2-5. Key
As shown below, plug the key or electronic keyer in-
to the KEY jack on the back panel. {f the plug does
Not fit, use a commercially available conversion plug
or wire the supplied 3.5 mm dia. plug as shown
below.
Manual key of electromc heyer
Connect as shown.
Ensure proper electronic keyer polarity.

4. OPERATION
4-1. CONTROLS AND THEIR FUNCTIONS @
4-1-1. Front panel
OD ‘5:
| |
(With the TR-851E/751E)}
A KENWOOD “144MHz ALL M(
Note: E 2
All segments on the Display Panel and Indicators are
shown on for this explanation.
@ @® Up/Down (¥ MHz/M.CH A) keys
Use these keys to step frequencies [in the VFO A or
VFO B mode] and Memory Channels [in the MR
(Memory Recall) mode] UP or DOWN.
Note; - —
When the FUNC (Function) indicator is ON, the Down
(¥ MHz) key functions as the F.LOCK (Frequency
Lock) and the Up (M.CH 4) key as the AL (Alert) key.
F.LOCK (Frequency Lock) key
Disables the TUNING knob, keys, and switches and
locks the selected frequency and other settings.
This function is active when the FUNC is ON and
F.LOCK key is pressed.
AL (Alert) key
This switch is used to check the priority channel
(M.CH1). When this switch is depressed M.CH1 will
be checked at about 6-second intervals. This func-
tion is active, when the FUNC is ON and the AL key
is pressed.
@ VOICE key
Press this key to activate the optional voice syn-
thesizer unit VS-1.
TONE key (TR-851A/751A only)
Activates the optional subaudible tone encoder
(TU-7) when it is installed.
This function is active when the FUNC is ON and
TONE key is pressed.
10
vot —@)—SOL RIT —2)— RE
18 PUSH ON i 0 ~~
“FS
MIN AA. af g
@ FUNC (Function) key
Pressing this key changes the functions of the
Up/Down (WV MHz/M.CH &) keys to the F.LOCK and
AL keys and the VOICE key to the TONE key (TR-
851A/751A only). FUNC indicator is ON when the
FUNC key is in the ON position. Each time this key is
pressed, the FUNC indicator alternates.
©) Display panel
The large LCD displays operational information such
as transmit/receive frequencies and memory channel
informations. (See page 12.)
© S & RF meter
This meter operates as the S meter during reception
to indicate signal strength and operates as the RF
meter during transmission to indicate relative
transmit power output.
This meter is set to point approximately to ‘’8’’ in
the high power mode.
Note: : —
The RF meter is calibrated with a 50-ohm dummy
load; the meter readings will differ when the anten-
na’s SWR is high.
S meter

I] C=) ES) 9)
SCAN Mt OFFSaT AB
@)_ BUSY indicator
The BUSY indicator lights when the squelch circuit
opens in the receive state. (It allows the operator to
obtain a visual indication of station activity.) When
the SQL control is turned fully counterclockwise,
this indicator is lit.
COM (Common channel) indicator
(TR-/851A/751A only)
This indicator is ON in the COM mode.
@) ON AIR indicator
The ON AIR indicator lights during transmit.
0} DCL system keyboard
These keys are used to operate the DCL system
when the optional MU-1 modem unit is installed.
(See pages 25 and 43.)
4 Microphone jack
Plug the standard or optional microphone into this
jack.
Microphone connector (Front view)
+ GND (STBY)
+ Microphone ev 1 GNO MICE
< PTT (STBY) .\\\
switch
OOWN- — 5 8 ViMax.
15 mA
a2 Mode/Numeric keypad
(See page 13)
(3) TUNING knob
Turn the knob clockwise or counterclockwise to
tune to the desired transmit/receive frequency. You
can also use the knob to select tone frequencies and,
in the DCL operation, digital codes.
@4 RF GAIN control
Use the RF GAIN contro! to adjust the gain of the
receiver high-frequency amplifiers circuit. Turn the
knob fully clockwise for maximum gain and fully
counterclockwise for minimum gain. (In the SSB and
CW modes, the gain can be controlled thru range of
60 dB or more; in the FM mode, in a range of 40 dB
or more.) In the SSB and CW modes, turning the RF
GAIN contro! fully counterclockwise deflects the S
meter to full scale and can reduce the internal noise.
In the FM mode, the S meter deflection is not af-
fected. Adjust the gain when a high-power signal is
received or there is interference from a powerful
signal near the receive frequency. Normally the con-
trol should remain full clockwise.
5) RIT (Receiver Incremental Tuning) knob
The RIT knob enables you to fine-tune a incoming
receive signal without changing the transmit fre-
quency in the SSB or CW mode. The knob operates
only when the RIT switch is in the ON position.
46; SQL (Squelch) control
The SQL control is used to eliminate noise during no
signal periods. Normally, this control is adjusted
clockwise until the noise just disappears and the
BUSY indicator goes OFF {Threshold level). For scan
operation, this control must be set to the threshold
point. This contro! functions in all modes. When an
incoming signal is weak or unstable, readjust the
squelch for optimum reception.
42 VOL (Volume) contro!/POWER switch
Press the POWER switch to turn the power ON;
Press it again to turn the power OFF. Turn the VOL
control clockwise to increase the volume turn it
counterclockwise to decrease the volume.
(8) NB (Noise Blanker) switch
The noise blanker eliminates impulse noises such as
automobile ignition noise. When the NB switch is
turned on, noises are reduced or eliminated to pro-
vide the optimum reception of weak signals.
Note:
This switch does not operate in the FM mode.

49) COM (Common channel) switch (With
the TR-851A/751A)
The COM switch selects the COM channel {common
frequency) by the use of a single keystroke operation.
The frequency has been factory-set to 433.00 MHz
with the TR-851A and 145.00 MHz with the
TR-751A, but may be reset to any desired frequency.
TONE switch (With the TR-851E/751E)
This switch activates the
{1,750 Hz) circuit.
repeater control tone
20; LOW switch
Press this switch to select low power transmit out-
put; press it again to restore high power transmit
output.
When this switch is pressed, the transmit output
levels change as follows:
HIGH: 25W
LOW: approx. SW
2) RIT switch
Press this switch to enable RIT; press it again to
disable RIT.
Set the RIT switch to ON; the RIT indicator lights. Turn
the RIT knob to vary the receive frequency.
If you press the RIT switch in the FM mode, a series of
beeps will sound indicating the RIT feature is not
enabled.
i
. Display panel
F.STEP display:
AL display:
VFO display:
MR display:
OFFSET display:
Tone display:
LOCK display:
REV display:
CHL display:
C.SQ display:
Channel display:
Stand by indicator:
50 Hz display:
kHz dot:
Frequency display:
MHz dot:
RIT display:
14 1312 10 10 9
ON when the F.STEP is ON.
ON when using AL.
ON when VFO A or VFO B is
selected.
ON when MR is. selected
(Memory channel operation).
ON when shift is set to’ +°'
or =" (“D-A’ or ‘D-B”
with the TR-851E European
version) using the OFFSET
key.
ON when TONE is selected.
ON when F.LOCK has been
selected.
ON when using the REV
function.
Flashes during open channel
search by CHL key. ON after
channel linkage.
ON when using C.SQ (Code
squelch).
Normally displays memory
channel; displays code chan-
nel during digital code
display.
Specifies which codes will
be actively used.
ON when the second digit is
5; OFF when it is O.
ON when 50Hz step is
selected; flashes during scan.
Frequency, tone frequency,
digital code, and call sign.
Flashes during scan.
ON when using RIT.

B. Mode/Numeric keypad
These numeric keypad (1 through 9 and 0) are used
to:
(a) Enter data to memory.
(b) Input your station call sign and digital! code to be
used by the DCL system.
@® AUTO key
Press this key to enter the AUTO mode; press any
other mode key to cancel the mode selection. In
AUTO, the mode corresponding to the dial frequency
is automatically selected. Normally, use the
transceiver in the AUTO mode. (Refer to section
4-2-5.)
(2) FM/LSB key
Press the FM/LSB key to alternate between FM and
LSB.
@ USB/CW key
Press the USB/CW key to alternate between USB
and CW.
‘4: REV (Reverse) key
Use this key to reverse the transmit/receive frequen-
cies during repeater operations. Press the REV key to
turn the function on; press it again to turn the func-
tion off.
(5; MR (Memory Recall) key
Activates memory channel operation.
Pressing this key causes the MR indicator to light
and the current memory channel information to be
displayed. There are 10 memory channels, O
through 9. They can be selected by using the A and
Vv keys described in (1), “3! or the UP and DWN
switches on the microphone. When the A/B key is
pressed, VFO operation is restored.
“6; F.STEP (Frequency Step) key
Use the F.STEP key to change the tuning step.
Each time it is pressed, the function will be turned
ON or OFF. Several step sizes are available depen-
ding upon the mode and position of the F.STEP key.
{Refer to Section 4-2-4.)
‘7) SCAN key
Press the SCAN key to initiate scanning; press it
again to stop scanning.
<8: M (Memory enter) key
Press the M key to write a frequency into a memory
channel or the COM channel (TR-851A/751A only).
When the key is pressed, a series of beeps will sound
for about 1.5 seconds. To enter a frequency, press
the desired numeric key or the COM key during the
time that the beeps are sounding.
‘9: OFFSET key
The OFFSET key is used to select the desired
transmitter offset for repeater operations. When the
key is pressed, the mode cycles from (+) shift, to
(—) shift, to simplex, and back to (+) shift.
When the offset function is ON, the symbol ‘+ °’ or
“H'' (DA of 7’D-B’’ with the TR-851E European
version) is displayed.
Note:
een
The
offset
function
is
used
only
in
the
FM
mode,
so
if
4
or
="
('D-A™
or
“'D-B’
with
the
TR-851E
European version) is displayed in the SSB or CW
mode, the shift function will not work.
‘10 A/B (VFO A/VFO B) key
{a) In the VFO mode
Switches operation between VFO A and VFO B.
(b) In the MR mode
Clears the MR state and restores VFO operation.
{c) in the COM mode (with the TR-851A/751A)
Clears the COM state and restores VFO operation.

4-1-2.
Rear
panel
®
@
@ EXT.SP (External speaker) jack
Use the 8-ohm EXT.SP jack to connect an external
speaker.
@) KEY jack
Provides
connection
for
the
CW
key.
Use
a
3.5
mm
dia. plug.
@) ANT (Antenna) jack
Provides connection for a 50-ohm antenna with a
male connector.
@) AUX (Auxiliary) jack
Provides connection for linear amplifier control. The
AUX jack is wired as shown below. For connection,
use the supplied 4-pin plug.
Both terminals will be
shorted on transmit
Relay contact capacity
ts 30 VDC.0.5 A.
ALC input
View from the rear panel
6) Fuse holder
Contains the following fuse:
TR-8514/851E: 8A
TR-751A/751E: 7A
® 13.8 vpc power supply jack
Provides connection for the standard 13.8 VDC
power supply. Insert the female end of the power
cable. Be sure that the red pin has ‘’+’’ polarity and
the black pin has ‘‘—’' polarity.
@ @) UP/DWN (Up/Down) switches
In
the
VFO
mode,
these
switches
step
frequencies
up
or
down
one
step.
When
held
down,
they
step
the
displayed
frequencies
up
or
down
continuously.
tn
the
MR
mode,
these
switches
step
memory
chan-
nels
up
or
down.
When
held
down,
they
step
the
memory
channels
up
or
down
continuously.
The
UP
switch
can
be
used
to
select
VFO
or
MR
operation,
and
the
DWN
switch
can
be
used
as
the
CHL
switch.
(Please
refer
to
Section
4-9.)
@
PTT
(Push
to
talk)
switch
When
this
switch
is
held
down
the
transceiver
will
be
placed
into
the
transmit
mode.
Operations
such
as
scan
are
cleared
when
the
switch
is
pressed.
@
16
Touch-Tone
key
(TR-751A
U.S.A.
version
only)
Used
to
activate
the
touch-tone
encoder.
(Autopatch
operation}

4-2. RECEPTION
4-2-1. Beep tones
Audible confirmation of microprocessor functions is
provided
in
the
form
of
a
series
of
audio
beeps.
The
volume of the beeps can be adjusted by an internal
potentiometer. (See page 36)
Beep tone Meaning
i Short beep ON. Frequency changed from upper limit to tower limit {or from lower limit to upper limit). ~]
1 long beep | orF. Channel 1 set during memory channel switching.
, 1 long beep Power turned on.
1 long beep Memory channel written.
2 short beeps
Memory 1 channel busy during alert.
3 short beeps:
Error (frequency out of range in OFFSET o or REV).
“4 short beeps (repeated) _
been pressed).
Send freuquency ready to be written to ‘memory (When memory channel 9 or O keys have |
5 short beeps
A key operated while LOCK light is ON.
"8 short beeps | Standby for memory write (For about . 5 seconds after M key is pressed}.
4-2-2. Initial setting
Connect the power supply and the antenna then set
the knobs and switches as follows:
VOL control : Fully counterclockwise
SQL control : Fully counterclockwise
RIT control ; Center
RF GAIN control: Fully clockwise
Other switches : All OFF
4-2-3, Reception
In the USB, LSB, and CW modes, the noise level is
generally low, so you can usually operate with the
SQL contro! full counterclockwise. This will also help
your weak signal reception.
1. Press the POWER switch; the display panel will
indicate as shown below and the Meter, the
Mode (AUTO and FM with the TR-851A, AUTO
and CW with other models) and the BUSY lights
will turn on.
(With the TR-851A/851E}
a ee ee |
Weigel f
(With the TR-751A/TR-751€)
Ej
U AA
Litt | fj
Note:
If the display is not as shown, reset the micro-
processor using the procedure in section 4-4-2.
2. Turn the VOL control clockwise until a QSO or
noise is heard; adjust for the desired level.
Clockwise rotation of the control will increase
the volume and counterclockwise rotation will
decrease the volume.
3. To eliminate receiver noise during no-signal
periods, slowly adjust the SQL contro! clockwise
until the noise disappears and the BUSY in-
dicator goes OFF (threshold point).
4. Rotate the TUNING knob to the desired frequen-
cy. When a signal is received the S meter will
deflect and the BUSY indicator will light.
A. SSB zero beating
If the frequency of your station and the distant sta-
tion are not the same reception of a clear receive
signal may be difficult.
(Matching your station’s transmit frequency to the
distant station’s transmit frequency is called ‘‘zero
beating’)
(a) To zero in, first set the F.STEP key to OFF to
toughly tune the other station’s frequency in
5 kHz steps, then set the key to ON for fine tun-
ing. When the TUNING knob is slowly turned
clockwise in the USB mode, the receive signal
becomes lower in pitch. (The reverse effect
takes place in the LSB mode.) Rotate the TUN-
ING knob until! the clearest most natural sound is
heard.
{b
=
If the frequency of the other station deviates
during the QSO, set the RIT switch to ON and
rotate the RIT knob until a natural sound is again
received.
15

B. CW zero beating
Frequency selection in the CW mode is the same as
in the SSB mode.
(a) You can zero beat by rotating the TUNING knob
with the RIT switch OFF until the incoming CW
signal is 800 Hz (Note).
Relationship between transmit and receive fre-
quencies in CW mode.
|
800 Hz
beat tone
|
ke
|
'
|
{
=. ce
Displayert frequency YOOHZ Displayed frequency
4 ry
Loxal statien’s transmit
— frequency ~ Orstant station's
(Zoro beat®
BFO trequency auring reception
Note: .—— ——
In CW receive operation, the BFO (Beat Frequency
Oscillator) is set 800 Hz below the transmit frequen-
cy.
With the transceiver, you can use the sidetone
oscillator frequency, about 800 Hz, as a guide for
zero beating.
(b) If the frequency of the distant station deviates
from 800 Hz or you wish to have a different
tone, set the RIT switch to ON and rotate the
TUNING knob until the desired tone frequency is
obtained.
4-2-4. Frequency selection
The transceiver contains two digital VFOs, VFO A
and VFO B, having a minimum tuning rate of 50 Hz
steps and 10 memory channels (1 thru 9, and O) for
easy selection of often used frequencies. The TR-
851A/751A also contains a COM channel. Normally
the TUNING knob would be used for frequency
selection, but thru the use of the MR, A/B, Up/Down
(V MHz/M.CH A) F.STEP and COM (TR-
851A/751A only) keys in combination with the
TUNING knob. Rapid frequency changes are possi-
ble.
A. 2 VFO {(A/B)
You can change frequencies using the TUNING knob
or the microphone UP/DWN switches. When VFO A
or VFO B is selected using the A/B switch, ‘’A’’ or
‘*B’’ appears on the display panel.
VFO A and VFO B independently store data such as
frequency, mode, RIT switch ON/OFF status, F.STEP
switch status, TONE status, off-set frequency, and
tone frequency (TR-851A/751A only).
Example:
Operating VFO A in FM and VFO B in SSB
VFO A: Yrs FM, F.STEP OFF
VFO B: S4ba8 USB, F.STEP ON
B. MR (Memory Recall) channels
Press the MR key; ‘’MR’’ will appear on the display
panel, indicating that the transceiver is in the
memory channel call state. Press the A/B key to
return the unit to VFO A or VFO B.
Memory recall can be selected using the Up/Down
(V MHz/M.CHA) key or the microphone UP/DWN
switch while ‘‘MR’’ is displayed on the panel
(Memory entry instructions, see page 19}. When the
TUNING knob is rotated while ‘‘MR’’ and the fre-
quency of the selected memory channel are
displayed on the panel, memory channel operation
will be cancelled and the transceiver will return to
VFO operation. Frequencies can be changed using
the VFO by noting the frequency selected when
““MR’’ was on the display panel. (See ‘‘Memory
shift’’.)
C. COM (Common) channel
(With the TR-851A/751A)
Press the COM key; the COM indicator lights and the
COM channel mode is selected. Press the key again
to return to the previous mode. Pressing the MR key
while ‘‘COM” is displayed selects the memory
channel mode; pressing the A/B key selects VFO A
or VFO B.
Note: --- -
When ‘’COM” is displayed, frequencies cannot be
changed using the TUNING knob, the W MHz/
M.CH A key, or the microphone UP/DOWN switches.
The COM channel! is factory-set to 433.000 MHz
with the TR-851A and 145.000 MHz with the TR-
751A, but may be reset to any desired frequency.
(See page 19)
OD. Frequency step
The step size in which frequencies are changed by
the TUNING knob or the microphone’s UP or DWN
push buttons can be changed by the SCAN key, the
mode key and/or the F.STEP key.
i TR-851E
TR-851A TRI51A ) aR75IE
on | oFF | ON | orr | ON
5 | 5 | 10 |125/ 5 |
KHz | KHz | kHz | kHz | kHz
BOHZ| 5 | 50 Hz| 5 !|50Hz
T kHz) kHz | 1 kHz| kHz | 1 kHz

E. Memory shift
This feature shifts the memory channel data to the
VFO. This will allow you to alter the frequency or
mode without changing the contents of the memory
channel. ‘‘MR’’ disappears from the display panel
and ’‘A”’ or ‘‘B’’ (The VFO used before the memory
channel operation was started) appears. Press the
MR key to return to the memory channel.
4-2-5. Mode selection
A. Manual mode selection
Most operations can be performed in the AUTO
mode. In the following operations, you must select
the appropriate mode using the FM/LSB and
USB/CW keys (when any of these keys is pressed,
the AUTO mode is released):
{a) TX QSY (Change frequency while transmitting)
for satellite communication or other applica-
tions.
{b}) Memory channel mode scan.
Present mode| New mode | Key
AUTO
LSB
cw
isp | FM/LSB
B. AUTO mode
The AUTO mode function automatically sets the
mode to correspond to the selected frequency as
shown below, which is especially convenient for
mobile operations.
Note: -
During transmission in the AUTO mode, TX QSY is
disabled. To switch frequencies while transmitting
for satellite communication or other similar applica-
tions, select USB, LSB or CW.
(With the TR-851A)
430.0 435.0 438.0 440.0
[_ FM LSB | FM
(With the TR-851E)
430.0 432.15 432.5 435.0 438.0 440.0
cw | uss | rm LSB FM
(With the TR-751A)
144.0 144.3 144.5 145.8 146.0 148.0
[ cw | use | eM uss | FM
(With the TR-751E)
144,00 144.15 - 144.50 145.85 146,00
| cw | use FM usB_|
C. Audible mode announcement
When a mode key is pressed, the first character of
the new mode is sounded in Morse code thru the
speaker.
4-2-6. AGC (Automatic Gain Control)
In the SSB and CW modes, the AGC circuit
minimizes the variation in the sound output caused
by variations in the incoming receive signal strength.
The AGC time constant is automatically set by mode
as follows:
USB and LSB....SLOW

4-3. TRANSMISSION
4-3-1. Precaution
Before transmitting check the frequency for activity
so that you do not interrupt another QSO.
rhe 2. FM, SSB (USB, LSB) mode
Connect the microphone and press the PTT
switch. The transceiver will enter the transmit
mode and the ON AIR indicator will light.
2. Speak into the microphone, holding the
microphone about 5 cm away from your mouth.
Close talking or talking too loudly may reduce
transmission clarity or spread the side bands too
much.
3. Release the PTT switch to return to receive ;
ON AIR indicator will OFF.
the
4-4. MEMORY
4-4-1. Microprocessor memory back-up
A lithium battery is contained in the transceiver to re-
tain memory. Turning off the POWER switch,
disconnecting the power cable, or a power failure
will not erase the memory. The battery should last
for approximately five years. When the battery
discharges, an erroneous display may appear in the
display.
4-3-3. CW mode
A. Semi break-in
Switching between transmit and receive in the CW
mode is performed using semi-break-in. In semi-
break-in, when the key is closed, transmit is
automatically selected when the key is opened,
receive is selected, after a short delay. You can thus
switch between transmit and receive automatically
by using the key alone. The time (or the delay) bet-
ween opening the key and returning to the receive
state can be internally adjusted. (See page 35}
B. Sidetone oscillator
The transceiver contains a sidetone oscillator circuit
to permit you to monitor your own signal. If the key
is closed in a mode other than CW, transmit will not
be selected but a sidetone will comes out of the
speaker, to allow Morse code training. The volume
of the sidetone can be adjusted internally.
(See page 35.)
(For the lithium battery replacement, refer to section
5-5.)
4-4-2. Initial state and reset of the microprocessor.
A. Initial state of the microprocessor from the fac-
tory.
iN MODEL TR-851A ; TR-851E TR-751A est TR-751E
Frequency Frequency Frequency Frequency
cHaNnet\| (MHz) Mode (MHz) Mode (MHz) Mode | (MHz) Mode
VFO A 430.000 {AUTO,FM | 430.000 |AUTO, CW | 144.000 /AUTO, CW | 144.000 |AUTO, CW
1
VFO B | 430.000 |AUTO,FM! 430.000 {AUTO,CW] 144.000 |AUTO, CW | 144.000 |AUTO, CW
| anaes, ; i
COM
433.000
{AUTO,
FM
——
—_—
145.000
|AUTO,
FM
=
A
M. CH1 430.000 |AUTO,FM | 430.000 |AUTO, CW [| 144.000 |AUTO,CW | 144.000 | AUTO, CW
_ 4 “=
M. CH7 430.000 FM 430.000 FM | 144.000 FM 144.000 FM
M. CH2 ~ (3
6.8.9.0 |7 77 T FM ae FM |- -—-—-.- FM —.-- FM
B. Microporcessor initialization
To erase all data from the memory or reset the
microprocessor , you may initialize the microproces-
sor from the front panel as follows:
Turn the POWER switch off.
2. Turn the POWER switch on while pressing the M
key.
Release the M key.

4-4-3. Memory channel
The 10 memory channels (1 through 9, and O) are
available for data entry. Channels 9 and O can store
transmit and receive frequencies separately for use
with ‘‘odd-split’’ repeaters. Channels 1, 7, 8, and O
have the following functions:
(a) Channel 1
Channel 1 is the priority alert channel.
Channel 7
Channel 7 contains the beginning frequency us-
ed during a search for an open channel when the
OCL system is operating.
Channel! 8
The frequency entered in channe! 8 is excluded
during the open channel scanning when the DCL
system is operating.
Channel 0
This channel is used to select the program scan
frequency range.
Note: a ——
These channel can BO used as normal memory chan-
nels when they are not used to perform these other
functions.
(b
(c
(d
4-4-4. Split memory
Channels 9 and O can store transmit and receive fre-
quencies separately. Use these channels when a
repeater system having an offset frequency other
than the offset shown in the table of Section 4-6-1.
OFFSET feature is used. They are useful for an
operations in which the transmit and receive fre-
quencies need to be different such as when the
Operating split frequencies during DX communica-
tions.
Storing the same transmit and receive frequencies in
these channels makes them operate as ordinary
memory channels.
Note:
Channels 9 and O can store frequencies in units of
100 Hz.
4-4-5. Data entry
In addition to frequency, the memory channels
can store such data as mode, F.STEP status,
offsets, TONE status (except TR-851£/751E Euro-
pean version), and TONE frequency (TR-851A/
751A only) as shown below.
S999" eee
CHANNEL ~
VFO A and VFO B
ies teesiar7s1a |
‘Frequency data
Mode data
F, STEP ON/OFF
RIT ON/OFF
OFFSET + —
TONE ON, OFF
Tone frequency data
________1R-8516/751E
European version U.K. version
|
Frequency
data
Frequency
data
Mode data Mode data
F.
STEP
ON/OFF
F.
STEP
ON/OFF
RIT ON/OFF RIT ON/OFF
OFFSET + — (TR-751E} OFFSET + —
OFFSET D-A D-B (TR-851E) TONE ON, OFF
M.CH1~8
Frequency data
Mode data
F, STEP ON/OFF
OFFSET + -
TONE ON, OFF
Tone frequency data
Frequency data
Frequency data
Mode data Mode data
F. STEP ON/OFF F. STEP ON/OFF
OFFSET + — (TR-751E) OFFSET + —
OFFSET D-A D-B (TR-851€) TONE ON, OFF
M. CH 9 and 0
Frequency data
Transmit frequency data
Mode data
F. STEP ON/OFF
TONE ON, OFF
Tone frequency data
Frequency data
Transmit frequency data
Mode data
F, STEP ON/OFF
Frequency data
Transmit frequency data
Mode data
F. STEP ON/OFF
TONE ON, OFF
COM (Common)
channel
Frequency data
Mode data
OFFSET + —
TONE ON, OFF
Tone frequency data

A. ENTRY of the current display data (i.e., frequency and mode)
channel 9 or O.
Operation Key Bee Remarks
Press
M
key
M
8
Beeps
Press
M
key
while
the
beeps
are
sounding
(about
1.5 seconds}.
This beep indicates the completion of data entry
Press the desired 1to8 Long beep (completed).
channel key. One toni
ig, 4 P 2
9orO short beeps Perform this operation for channel 9 or O.
Press 9 or O again for Long beep The same frequency is stored for both transmit
and receive. (Completed)
B. Displayed data (i.e., frequency and mode) is dif-
ferent from the data to be stored.
Note:
Operation
Select the frequency to be stored.
1. Following step 2, set the F. STEP ON/OFF, OFF-
SET and TONE (except TR-851E European ver-
sion) as required. (TR-851A/851E only}
2. Following step 2, set the F.STEP ON/OFF as re-
quired. (TR-751A/751E only)
Select the mode.
Select the offset information.
Select the tone information. (Except TR-851E/
751E European version)
Operations 1 to 3 of A above.
——
Operation
Select the receive fre- y
_[.quency, "1."
Set 2 to 4 of B above.
Press the M key.
Vv, a. F.STEP
4 Press the desired
channel.
g9o0r9O
1 long,
4 short beeps
Remarks
Refer to B above.
Beep to request transmit frequency storage keeps
sounding until the transmit frequency has been
entered,
Select the transmit TUNING knob . heaps
continiously See Note.
frequency Vv, A, F.STEP
fl. repeated
Press the same key as
in'4 above: tong beep” Storage completed.
Note;
—————__
sss
;
=
When the repeated 4 beeps sounds during a split M keys are invalid. This beep keeps sounding after
memory storing operation (Memory channel 9 or 0),
all keys except the TUNING knob, V, A F.STEP, and
the power is turned on or off. To silence it, press the
9 or O key.
“.
D. Storing data into the COM channel (With the TR-851A/751A)
Operation Key Beep Remarks
1 | Select frequency. ee are = amas frequency to be stored in the COM
2 bbasisrat eines desired - - Perform operations 1 to 4 in B above.
3 | ress ne my o.oo eee ee
4 | Press the COM key. COM Long beep hs eo aa orale aes been stored in
20