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INSTRUCTION MANUAL HF/VHF ALL MODE TRANSCEIVER
I746PRO

This device complies with Part 15 of the FCC rules. Operation is subject
to the following two conditions: (1) This device may not cause
harmful interference, and (2) this device must accept any interference
received, including interference that may cause undesired operation.

FOREWORD
We understand that you have a choice of many different radios in the market place. We want to take a
couple of moments of your time to thank you for making the IC-746PRO your radio of choice, and hope you
agree with Icom’s philosophy of “technology first”.Many hours of research and development went into the
design of your IC-746PRO. Rather than completely redesigning all areas to create
a new radio, the engineering team at Icom decided to follow in the footsteps of the IC-746
(one of the best value transceivers in the marketplace) with the new
“PRO.” Focused on real world improvements compiled over the last few years from letters, phone calls,
EMails and newsgroup postings, the engineering team at Icom is proud to say “many of these changes were
compiled from a list of suggestions from you, the amateur radio operator!”
FEATURES
• 32-bit Floating point DSP and 24-bit AD/DA converter
• DSP IF Filter creates 102 types of filter
• All mode capability covering 160–2 m
• 100 Watt continuous duty cycle
• All mode digital modulation and demodulation
• RTTY demodulator and decoder
• Twin Pass Band Tuning
• RF speech compression with selectable pass band
• Microphone Equalizer
• SSB/CW synchronous tuning
IMPORTANT
READ THIS INSTRUCTION MANUAL
CAREFULLY before attempting to operate the transceiver.
SAVE THIS INSTRUCTION MANUAL. This manual contains important safety and operating instructions
for the IC-746PRO.
EXPLICIT DEFINITIONS
DEFINITION WORD
RWARNING
Personal injury, fire hazard or electric shock may occur.
CAUTION Equipment damage may occur.
NOTE
If disregarded, inconvenience only. No risk or personal injury, fire or electric shock.
i
PRECAUTIONS
RWARNING RF EXPOSURE! This device emits Radio Frequency (RF) energy. Extreme caution should be
observed when operating this device. If you have any questions regarding RF exposure and safety standards
please refer to the Federal Communications Commission Office of Engineering and Technology’s report on
Evaluating Compliance with FCC Guidelines for Human Radio
Frequency Electromagnetic Fields (OET Bulletin 65).
RWARNING HIGH VOLTAGE! NEVER attach an antenna or internal antenna connector during transmission.
This may result in an electrical shock or burn.
NEVER apply AC to the [DC13.8V] jack on the transceiver rear panel. This could cause a fire or ruin the
transceiver.
NEVER apply more than 16 V DC, such as a 24 V battery, to the [DC13.8V] jack on the transceiver rear
panel. This could cause a fire or ruin the transceiver.
NEVER let metal, wire or other objects touch any internal
part or connectors on the rear panel of the transceiver.
This may result in an electric shock.
NEVER expose the transceiver to rain, snow or any liquids.
AVOID using or placing the transceiver in areas with temperatures
below –10°C (+14°F) or above +60°C (+140°F).
Be aware that temperatures on a vehicle’s dashboard can
exceed 80°C (+176°F), resulting in permanent damage to
the transceiver if left there for extended periods.
AVOID placing the transceiver in excessively dusty environments
or in direct sunlight.
AVOID placing the transceiver against walls or putting
anything on top of the transceiver. This will obstruct heat
dissipation.
Place unit in a secure place to avoid inadvertent use by
children.
During mobile operation, DO NOT operate the transceiver
without running the vehicle’s engine. When the transceiver’s
power is ON and your vehicle’s engine is OFF,
the vehicle’s battery will soon become exhausted.
Make sure the transceiver power is OFF before starting
the vehicle. This will avoid possible damage to the transceiver
by ignition voltage spikes.
During maritime mobile operation, keep the transceiver
and microphone as far away as possible from the magnetic
navigation compass to prevent erroneous indications.
BE CAREFUL! The heatsink will become hot when operating
the transceiver continuously for long periods.
BE CAREFUL! If a linear amplifier is connected, set the
transceiver’s RF output power to less than the linear amplifier’s
maximum input level, otherwise, the linear ampli-
fier will be damaged.
Use Icom microphones only (supplied or optional). Other
manufacturer’s microphones have different pin assignments,
and connection to the IC-746PRO may damage
the transceiver.
FOREWORD ........................................ i
IMPORTANT ........................................ i
EXPLICIT DEFINITIONS ..................... i
PRECAUTIONS ................................... i
TABLE OF CONTENTS ...................... ii
QUICK REFERENCE GUIDE ........ I.X
Installation ....................................... I
Operation ....................................... III
. Your first contact ........................... IV
Ready to call CQ? ......................... IX
1 PANEL DESCRIPTION ........... 1.12
Front panel ..................................... 1
Rear panel ...................................... 7
LCD display .................................... 9
Multi function switches .................. 11
Microphone (HM-36) .................... 12
2 INSTALLATION AND
CONNECTIONS ................... 13.17
Unpacking .................................... 13
Selecting a location ...................... 13
Grounding ..................................... 13
Antenna connection ...................... 13
Required connections ................... 14
. Advanced connections ................. 15
. Power supply connections ............ 16
. Linear amplifier connections ......... 17
. External antenna tuner
connections .................................. 17
3 BASIC OPERATION ............. 18.25
. When first applying power
(CPU resetting) ............................. 18
. Initial settings ................................ 18
. Selecting an operating band ........ 19
. Selecting VFO/memory mode ...... 20
. VFO operation .............................. 20
. Frequency setting ......................... 21
. Operating mode selection ............ 23
. Volume setting .............................. 23
. Squelch and receive (RF)
sensitivity ...................................... 24
. Basic transmit operation ............... 25
4 RECEIVE AND TRANSMIT .. 26.46
. Operating SSB ............................. 26
. Operating CW ............................... 27
SUPPLIED ACCESSORIES
The transceiver comes with the following accessories.
q DC power cable (OPC-025D) ............................ 1
w Hand microphone (HM-36) ................................ 1
e Spare fuses (FGB 30 A) .................................... 2
r Spare fuse (FGB 5 A) ........................................ 1
t CW keyer plug (AP-330) .................................... 1
Icom, Icom Inc. and the logo are registered trademarks of Icom Incorporated (Japan) in the United States, the United Kingdom,
Germany, France, Spain, Russia and/or other countries.
Qty.
TABLE OF CONTENTS
. Electronic keyer functions ............ 29
. Operating RTTY (FSK) ................. 35
. RTTY functions ............................. 36
. Operating AM ............................... 40
. Operating FM ............................... 41
. Repeater operation ....................... 44
5 FUNCTIONS FOR RECEIVE
........................................... 47.54
. Simple band scope ....................... 47
. Preamp/Attenuator ....................... 48
. RIT function .................................. 48
. AGC function ................................ 49
. IF filter selection ........................... 50
. IF (DSP) filter shape ..................... 51
. Noise blanker ............................... 51
. Meter peak hold function .............. 51
. Twin PBT operation ...................... 52
. Noise reduction ............................ 53
. Notch function .............................. 53
. Dial lock function .......................... 53
. Voice squelch control function ...... 54
6 FUNCTIONS FOR TRANSMIT
........................................... 55.61
. VOX function ................................ 55
. Break-in function .......................... 56
. ¡ÓTX function ................................ 57
. Monitor function ............................ 57
. Speech compressor ..................... 58
. Transmit filter width selection ....... 58
. Split frequency operation .............. 59
. Quick split function ....................... 60
. Measuring SWR ........................... 61
7 MEMORY OPERATION ........ 62.68
. Memory channels ......................... 62
. Memory channel selection ............ 62
. Programming a memory ............... 63
. Memory clearing ........................... 63
. Selecting the call channel ............. 64
. Programming the call channel ...... 64
. Frequency transferring ................. 65
. Programming scan edges ............ 66
. Assigning memory names ............ 67
. Memo pads ................................... 68
8 SCANS ................................. 69.74
. Scan types .................................... 69
. Preparation ................................... 69
q w
e r t
. Voice squelch control function ...... 70
. Scan set mode ............................. 70
. Programmed scan/Fine programmed
scan .............................................. 71
. Memory scan operation ................ 72
. Select memory scan ..................... 72
. ¡ÓF scan operation and Fine ¡ÓF scan
...................................................... 73
. Tone scan/DTCS code scan
operation ...................................... 74
9 ANTENNA TUNER OPERATION
............................................ 75.77
. Antenna connection and selection 75
. Antenna tuner operation ............... 76
. Optional external tuner operation . 77
10 DATA COMMUNICATION ..... 78.80
. Connections ................................. 78
. Packet (AFSK) operation .............. 79
. Adjusting the TNC output level ..... 80
. Data transmission speed .............. 80
11 SET MODE ............................ 81.89
. General set mode ......................... 81
. Tone control set mode .................. 89
12 OPTION INSTALLATION ..... 90.91
. Opening the transceiver¡¯s case .... 90
. UT-102 VOICE SYNTHESIZER UNIT ... 90
. CR-338 HIGH STABILITY CRYSTAL UNIT
..................................................... 91
13 MAINTENANCE .................... 92.94
. Trouble shooting ........................... 92
. Fuse replacement ......................... 93
. Tuning dial brake adjustment ....... 93
. Resetting the CPU ........................ 94
. Frequency calibration (approximate)
..................................................... 94
14 CONTROL COMMAND ......... 95.99
. Remote jack (CI-V) information .... 95
15 SPECIFICATIONS...................... 100
16 OPTIONS.................................... 101
ii
QUICK REFERENCE GUIDE
. Installation
1. Install a ground system for DC noise suppression
and RFI suppression
2. Install your DC power supply
3. Install lightning protection. This will help protect
more than your gear.
1. Grounding your Shack
Although your radio will operate by connecting the DC
power supply and antenna, it is necessary to have a
good ground system in your shack. A ground connection
is the electrical contact between the common point
of an electrical or electronic system and the earth.
A good earth ground is necessary to prevent electrical
shock, eliminate problems from RFI and DC noise.
With more electronic devices being used today, it is
also important to reduce RFI and EMI. Although you
may not see interference in your shack, without a
grounding system, your neighbors may experience interference.
Even though many of these devices are
Part 15, where they must accept interference from
their surrounding environment, it is best to eliminate
as much of the possible interference from your shack.
If you do not have a grounding system for your shack,
depending on the location of your shack, basement or
ground floor, a good ground system can be as simple
as a couple of ground rods driven 6 to 8 feet into the
soil. When installing your IC-746PRO to your grounding
system, the shortest most direct connection is recommended.
NOTE: There are many publications covering
proper grounding techniques. Check with your local
dealer for more information and recommendations.
2. Installing your DC Power Supply
The DC power supply is a device used to convert
110/220 V AC, also know as Household current, to a
steady source of 13.8 V DC.
The perfect match to your IC-746PRO is the PS-125.
This compact switching power supply is the matching
power supply for your IC-746PRO with a current rating
of 25 A continuous duty. This plug and play unit
plugs into the DC jack located on the rear of the radio.
Transceiver PS-125 DC power
socket
DC power cable
Connect to an AC outlet using the supplied AC cable.
I
4. Install and connect an antenna system for the appropriate
bands of operation
5. Connect other peripheral equipment. This includes
microphones, headsets, TNC, amplifiers and any
other equipment necessary to make your shack
complete.
RWARNING!: NEVER ground station equipment
or antennas to house gas lines. NEVER attach
ground lines to plastic (pvc) pipe.
D Some Symptoms if inadequate grounding
a. Poor DC Ground
60 Hz hum on the audio either Rx or Tx without the
antenna connected.
If you feel a tingling sensation when you touch a
metal surface. Surfaces such as the cover of your
radio or power supply.
b. Poor RF Ground
While transmitting and you feel a tingling sensation
when you touch a metal surface. Surfaces such as
the cover of your radio or power supply.
While transmitting, you experience interference to
other electronic devices, such as the telephone,
television or stereo audio systems.
• If you are not using the PS-125:
Connect the supplied DC power cable (OPC-025D) to
the appropriate color coded terminals, then insert the
DC connector into the DC jack located on the rear of
the radio.
Transceiver AC
outlet
to DC power
socket
A DC power
supply*
Red Black
Supplied
AC cable DC power cable *13.8 V; at least 23 A
continuous
+ _
30 A fuses
NOTE: Although the power supply current requirement
is quite low during receiving, this not the case
when you transmit. With many electrical devices in
the shack, it is very important to verify the electrical
circuit is not overloaded.
3. Installing lightning protection
Although you may not live in an area with high occurrence
for lightning storms, it is always wise to take
precautions for lightning or static discharges. Proper
lightning protection not only offers protection to the
ham gear, but the shack and most importantly the operator.
4. Installing your antenna system
Whether your IC-746PRO is your first radio or one of
many, one of your key elements in a great shack is
the antenna system. There are three connections on
the back of your IC-746PRO, two for HF and 6 m and
one for 2 m. If you are using one antenna for HF and
6 m, for simplicity, connect the antenna coax to ANT1.
ANTENNA 1, 2
[Example]: ANT1 for 1.8.18 MHz bands
ANT2 for 21.50 MHz bands
144 MHz ANTENNA
Connect a VHF (60.144 MHz)
antenna; impedance: 50 §Ù.
Your IC-746PRO is equipped with an internal antenna
tuner (ATU) for operation on 160.6 m. This ATU is designed
to work with an unbalanced 50 §Ù feedline. The
purpose of the internal antenna tuner is to match the
impedance of your antenna system to as close to a
50 §Ù load as possible. This ATU will not operate with
a long wire or ladder line (450 §Ù or other balanced
feedlines). An external ATU such as the AH-4 would
be necessary for this kind of operation.
QUICK REFERENCE GUIDE
NOTE: There are many publications covering
proper lightning protection, check with your local
dealer for more information and recommendations.
30 mm Slide the coupling ring
down. Strip the cable
jacket and soft solder.
Soft
solder
1.2 mm
Strip the cable as
shown at left. Soft solder
the center conductor.
solder solder
Slide the connector
body on and solder it.
Screw the coupling
ring onto the
connector body.
Antenna SWR
Each antenna is tuned for a specified frequency
range and SWR may be increased out-of-range.
When the SWR is higher than approx. 2.0:1, the
transceiver¡¯s power drops to protect the final transistors.
In this case, an antenna tuner is useful to
match the transceiver and antenna. Low SWR allows
full power for transmitting even when using the
antenna tuner. The IC-746PRO has an SWR meter
to monitor the antenna SWR continuously.
PL-259 CONNECTOR INSTALLATION EXAMPLE
q
10 mm (soft solder) Coupling ring
w 10 mm
e
r
30 mm . 9.8 in 10 mm . 3.8 in 1.2 mm . 1.16 in
RWARNING: Although a mag mount antenna
works great on a vehicle, DO NOT use the IC-
746PRO with this type of antenna.
CAUTION: Although your IC-746PRO has protection
to drop down power with a high SWR, this
does not completely protect the transceiver from
transmission without an antenna. Make sure you
have an antenna connected whenever you transmit
with your radio.
NOTE: There are many publications covering
proper antennas and their installation, check with
your local dealer for more information and recommendations.
II
QUICK REFERENCE GUIDE
If you do not see the particular item you are wanting
to connect, refer to the Advance Connections section
starting on page 15.
MICROPHONES
SM-20 HM-36
b. Straight Key: Use a 6.35(d) mm (1.4) mono plug
and connect key to the back of the radio.
c. External Keyer: Use a 6.35(d) mm (1.4) mono
plug and connect to the back of the radio.
d. Computer Keying: Use a 6.35(d) mm (1.4) mono
plug and connect to the back of the radio.
STRAIGHT KEY
(+)
5. Connect other peripheral equipment
Everyone has his or her favorite ad-on gear; now is
the time to connect this gear! We will cover the basic
devices that can be connected to your IC-746PRO.
(dot)
(com)
(dash)
(_)
. Operation
1. Voice
Microphones: Connect the microphone to the eightpin
connector on the front of the radio.
2. CW
CW Key: There are several types of keys or keyers
that can be used with your IC-746PRO.
a. Iambic Key paddle: Use a 6.35(d) mm (1.4) stereo
plug and connect to the [ELEC-KEY] jack located
on the front of the radio.
CW KEY
A straight key can be used when the internal
electronic keyer is turned OFF in keyer set
mode. (p. 34)
NOTE: You will need to select the type of keyer you
are using in the Keyer Set mode. There are many
advanced CW functions in this set mode. Until you
have a full understanding of these functions
change only the items necessary.
III
3. Other convenient items
Headphones:
A 6.35(d) mm (1.4) mono jack for operation without
using the internal or external speakers. Perfect for operation
without disturbing others in the room.
HEADPHONES
. Your first contact
Now you should have your IC-746PRO installed in
your shack, and like a kid on his birthday, you are
probably excited to get on the air. We would like to
take you through a few basic operation steps to make
your first gOn The Airh an enjoyable experience.
D Getting started
1. Before powering up your radio, you may want to
make sure the following controls are set in the following
positions:
. [AF] : Commonly referred to as the volume:
fully counter clockwise.
.[NR] : The noise reduction control: fully
counter clockwise.
. [MIC GAIN] : The mic gain: fully counter clockwise.
.[RF/SQL] : The control for the RF Gain and
Squelch circuits: 12 ofclock.
.[CW PITCH] : The control for the CW pitch:
12 ofclock.
.[KEY SPEED] : Internal CW Keyer Speed: fully
counter clockwise
.[NOTCH] : Control for the manual notch:
12 ofclock
QUICK REFERENCE GUIDE
External Speaker:
A 3.5(d) mm (1.8) mono jack for operation with an external
speaker. (Input impedance: 8 ./Max. input
power: 5 W)
EXTERNAL SPEAKER
SP-21 (optional)
2. Resetting the CPU: Although you have purchased
a brand new radio, some settings may be changed
from the factory defaults during the QC process. So
your radio can start from Factory Defaults resetting
the CPU is necessary.
[F-INP] [M-CL] [POWER]
IV
QUICK REFERENCE GUIDE
D Just listening
1. Select the desired band
On your IC-746PRO, an easy way of changing bands
is by using the keypad located just above the tuning
knob on the right hand side of the display. You will notice
each switch has two sets of numbers; one set of
numbers represents the band selection.
2. Tune to the desired frequency
Directly below the keypad is the tuning knob. This will
allow you to dial in the frequency you want to operate.
You will notice the tuning speed [TS] is 10 Hz resolution.
Page 22 will instruct you on how to set the
tuning speed [TS] for 1 Hz resolution.
3. Verify proper antenna has been selected.
You IC-746PRO has three antenna connectors. Two
for HF and 6 m and a one for 2 m. The selection for
2 m is automatic, where the HF and 6 m is user selectable
for either one of the antenna jacks. For first
time use, the antenna selector should show “ ” on
the display of your radio. Verify the antenna selected
on the display is the antenna port your antenna is
connected to.
4. Adjust audio output
Adjust this control to a comfortable audio level.
V
•Say you want to go to 20 meters or 14 MHz; you
would push the [14 5]. This will immediately change
the displayed operating frequency to the 20-meter
band. By pushing [14 5] again, frequency pre-sets
in the triple band stacking registers frequency can be
displayed. For more details on this system refer to
p. 19.
3.5 2 1.8 1 7 3
10 4 18 6 14 5
21 7 24 8 28 9
GENE 144 ENT 50 0
NOTE: Although you can directly enter the frequency
with the keypad, using the Band Stacking
Register and the tuning knob is the most popular
method of hoping around the bands. For more information
regarding the direct frequency entry
method, refer to p. 22.
Either “1” or “2” appears.
*No indicator appears during
144 MHz operation.
RF/SQL AF
Increases Decreases
No audio output Max. audio output
D What are you hearing?
Stop and focus on what you are hearing. Do you hear
a lot of noise? Is the signal intelligible? Are you set up
for the right mode? How about the filters?
1. Verify mode
Although your IC-746PRO will automatically select
USB or LSB in the HF bands, it will not select any of
the other modes. You will need to select the proper
mode whether CW, RTTY, AM or FM.
2. Reducing interference
Your IC-746PRO has many features to reduce QRM
and QRN from the desired signal.
a. Noise Reduction: The noise reduction system on
your IC-746PRO is part of the 32-bit DSP. This is
used to reduce the hiss and QRM levels. To activate,
push the [NR] switch located just to the right
of the [PHONES] jack.
[NR] [NR]
AGC DUP CMP TBW SCP
Appears
b. Adjusting the Noise Reduction: The noise reduction
is completely variable on how much of the
DSP Noise Reduction is used [NR] level control located
just above the [NR] switch.
QUICK REFERENCE GUIDE
CW/RTTY SSB AM/FM
Hint!
The Triple Band Stacking Register will memorize
the last three frequencies used in the band, as well
as the Mode, Filter, Tuner and AGC settings. This
makes band hoping much easier.
NOTCH NR
Decreases Increases
OFF
Noise reduction ON
Noise reduction OFF
Hint!
How far you advance the NR control will determine
how much the noise can be effectively reduced.
Turning the control too far clockwise may cause
some distortion to occur on the received signal. The
NR control should only be turned as far clockwise
as is necessary. Use this control, along with RF
gain, NB (noise blanker, if needed), and IF filters as
well, to minimize the effects of noise on the target
signal.
VI
QUICK REFERENCE GUIDE
c. Notch: There are two notch systems on your IC-
746PRO.
•Automatic: The automatic notch will track up to three
heterodynes. This is helpful for eliminating annoying
transmitter “tune up” tones on any band, and to minimize
continuous tone “heterodynes” encountered on
the 40 meter phone bands at night, for example.
Once selected an icon will appear “A NOTCH” on
the display.
Hint!
The Automatic Notch will not operate in the SSB
data, CW or RTTY modes.
•Manual: The Manual notch provides 70 dB of attenuation
to pin point an interfering signal. The 12 o’-
clock position is on the operating frequency, turning
the Notch knob clockwise moves the notch up the
band and counter clockwise will move the notch
down the band. Once selected an icon “NOTCH” will
appear on the display.
NOTCH NR
High frequency Low frequency
d. Filters: Your IC-746PRO has an incredible IF DSP
based filter network with over 100 settings.
• Dial in your filters: By pushing [FILTER] for 1 sec.,
you enter the filter set mode. This is where you are
able set the three filter presets. Across the bottom of
the display you will see the “BW” icon. The switch directly
below, along with the tuning dial, will be used
to select the changes you will make.
[FILTER]
AGC DUP CMP TBW SCP
The selected filter width is indicated
for approx. 1 sec. when [FILTER] is
pushed. Filter selection
VII
[A/NOTCH] [NOTCH]
BW
Shows the selected filter and passband width.
• Indication while setting
AGC DUP CMP TBW SCP
Notch function indicators
NOTE: Your IC-746PRO is equipped with multiple
AGC circuits. This allows the DSP to filter out interfering
signals and QRM, while also taking this interference
out of the AGC. Bottom line, this will either
eliminate or greatly reduce the pumping of the
AGC from the interfering signal.
• Filter set mode indication
Reverses Appears
BW
While pushing [F1 BW], rotate the tuning dial to set
passband width.
d. Filters:— continued
•On the fly adjustment: Once the adjustments have
been made in the filter set mode, you can make on
the fly changes by using the Twin Pass Band Tuning,
Twin PBT. You will be able to see the effects of the
Twin PBT on the upper left hand side of the screen.
One of “1,” “2” or “3” is
displayed for selected filter
number indications.
NOTE: The Twin PBT filters shift the two IF DSP
filters (See Diagrams below and right). This feature
allows both an IF shift as well as a narrowing of the
Pass Band. Although you can narrow the pass
band by shifting the two filters, this does not narrow
both filters, thus the filter shape is not narrowed.
You may hear some signal artifacts pass
through this filter adjustment.
Center
IF center frequency
Passband
pass band
desired signal inteference interference
PBT operation example
BW
Shows the selected filter and passband width.
• Indication while PBT setting
AGC DUP CMP TBW SCP
Passband width and shifting value are
indicated while [TWIN PBT] is operated.
• Filter set mode indication
Appears when PBT is used.
IF shift
IF center freq. interference
BW
Appears when passband is shifted.
*By pushing [PBTC] for 1 sec., the shifted value returns
to the default setting, and the “dot” disappears.
Passband
desired signal
QUICK REFERENCE GUIDE
[TWIN PBT] control
[PBTC]
VIII
QUICK REFERENCE GUIDE
3. RX Tone Control:
Once you have mastered your filter settings, one last
feature to enable the most intelligible audio is the actual
audio tone you hear. You can adjust the equalization
of your received audio ¡¾5dB.
q Push [MENU] several times, or until M2 is shown
on the display.
w Push [F4 TCN] for the Tone Control set mode.
e Push the appropriate mode switch to adjust SSB,
AM or FM.
r Push [F1 ¡Â] or [F2 ¡Ã] to change to the desired
component.
1. RX Bass
This item adjusts the bass level of the receive audio
tone from .5 dB to +5 dB in 1 dB steps.
2. RX Treble
This item adjusts the treble level of the receive audio
tone from .5 dB to +5 dB in 1 dB steps.
We hope these pointers have been helpful. Now you
are ready for the ¡°Ready to call CQ?¡±.
[NOTCH]: Max. CCW
HF/VHF TRANSCEIVER
F 2 F 3 F 4 F 1
MENU SSB
CW PITCH RF PWR KEY SPEED P.AMP/ATT
. Ready to call CQ?
[NR]: Max. CCW
POWER
TRANSMIT
[TRANSMIT]: OFF
PHONES
ELEC-KEY
MIC [AF]: Max. CCW
[RF/SQL]: 12 o¡¯clock
[MIC GAIN]: Max. CCW
[RF PWR]: Max. CCW
i746PRO
ANT TUNER
NOTCH NR
A/NOTCH NR
AF RF/SQL
MIC GAIN
[CW PITCH]: 12 o¡¯clock
1. Setting up your transmit audio
The 32-bit DSP in your IC-746PRO is capable of allowing
you to selects transmit audio for phone modes.
2. Mic Gain
The microphone gain is used for proper transmit
audio level for full output power.
IX
[F1 ¡Â] [F2 ¡Ã] [F4 TCN]
Tuning dial [MENU]
O
RX Bass SSB
3
O
F 5
FILTER CW/RTTY AM/FM
VOX/BK-IN MONITOR NB
RX Treble SSB
4
TWIN PBT
3.5 2 1.8 1 7 3
F-INP
10 4 18 6 14 5
21 7 24 8 28 9 SPLIT
MW PBTC
GENE 144 ENT 50 0 A/B
V/M M-CL
M-CH TS MP-W MP-R
TX RX
LOCK XFC
RIT CLEAR ¡ÓTX
RIT/¡ÓTX
CALL LOCK/
SPCH
[KEY SPEED]: Max. CCW
3. DSP TX Audio Pass Band
The capability of changing the pass band of your
transmit audio, is at your finger tips. Regardless of the
condition of the speech compressor, you can adjust it
by selecting the [F4 TBW].
You will find this located in the M1 menu. By pushing
[F4 TBW] for 1 sec. you can select the TX audio band
pass.
There are three levels of audio passband width available
(Wide, Mid, and Nar).
TX Audio Passband widths
: 2.8 kHz
: 2.4 kHz
Wide
Mid
: 2.2 kHz Nar
; Great Full Audio
; Great for operators with
deep full voices
; Great for breaking through
pile ups
4. Microphone Equalizer
Although these bandwidths are fixed, the Microphone
Tone Control will give you more audio control for your
voice operation on SSB, AM, and FM modes. Your IC-
746PRO is equipped with a very powerful equalizer
system with 121 possible combinations. This is
achieved by using the separate bass and treble adjustments.
The default for both the Base and Treble
is at 0 dB.
Entering Microphone Tone Control set mode:
q Push [MENU] several times, or until M2 is shown
on the display.
w Push [F4 TCN] for the Tone Control set mode.
e Push the appropriate mode switch to adjust SSB,
AM, or FM.
r Push [F1 ¡Ü] or [F2 ¡Ý] to change to the desired
component.
1. TX Bass
This item adjusts the bass level of the transmit audio
tone from ¨C5 dB to +5 dB in 1 dB steps.
2. TX Treble
This item adjusts the treble level of the transmit audio
tone from ¨C5 dB to +5 dB in 1 dB steps.
Verify you have selected a clear frequency
and call out your CQ!
QUICK REFERENCE GUIDE
AGC DUP CMP TBW SCP
F 5 F 4 F 3 F 2 F 1
Push [F4]
TX BW=WIDE
AGC DUP CMP TBW SCP
F 5 F 2 F 3 F 4 F 1
The selected transmit filter width
is displayed for approx. 1 sec.
Push [F4] for 1 sec. to select the transmit filter width.
[F1 ¡Ü] [F2 ¡Ý] [F4 TCN]
Tuning dial [MENU]
Hint!
Voice patterns and audio characteristics vary with
each operator, therefore the [MIC GAIN], DSP TX
Audio Pass Band and Microphone Tone Control
settings will be different for each operator. Actual on
air experimenting is necessary to get just the right
sound. Listen to your transmit audio with headphones
and the monitor function turned ON. It¡¯s
also best to test and adjust your audio on the air,
while someone who knows what your real voice
sounds like listens, and provides and opinion on
your audio quality.
TX Bass SSB
1 O
TX Treble SSB
2 O
X
w
e
r
1 PANEL DESCRIPTION
. Front panel
!6
POWER q
!7
TRANSMIT
PHONES
ELEC-KEY
MIC
F 1
MENU
KEY SPEED P.AMP/ATT
!5 !4 !3 !2
CW PITCH RF PWR
i746PRO
ANT TUNER
NOTCH NR
A/NOTCH NR
AF RF/SQL
MIC GAIN
y uio !0
.Push momentarily to turn power ON.
.Turn the optional DC power supply ON in advance.
.Push for 1 sec. to turn power OFF.
w TRANSMIT SWITCH [TRANSMIT]
Selects transmitting or receiving.
. The [TX] indicator lights red while transmitting and the
[RX] indicator lights green when the squelch is open.
e HEADPHONE JACK [PHONES]
. Output power: 5 mW with an 8 . load.
. When headphones are connected, the internal speaker
or connected external speaker does not function.
r ELECTRONIC KEYER JACK [ELEC-KEY] (p. 14)
Accepts a paddle to activate the internal electronic
keyer for CW operation.
. Selection between the internal electronic keyer, bug-key
and straight key operation can be made in keyer set
.A straight key jack is separately available on the rear
. Keyer polarity (dot and dash) can be reversed in keyer
.4-channel memory keyer is available for your conve-
(dot)
(com)
(dash)
!1
t
q POWER SWITCH [POWER]
Accepts headphones.
mode. (p. 34)
panel. See [KEY] on p. 7.
set mode. (p. 34)
nience. (p. 30)
1
HF/VHF TRANSCEIVER
F 2 F 3 F 4
SSB CW/RTTY AM/FM
VOX/BK-IN NB
t MICROPHONE CONNECTOR [MIC]
Accepts the supplied or an optional microphone.
. See p. 101 for appropriate microphones.
. See p. 12 for microphone connector information.
y RF GAIN CONTROL/SQUELCH CONTROL
[RF/SQL] (outer control)
Adjusts the RF gain and squelch threshold level.
The squelch removes noise output from the speaker
(closed condition) when no signal is received.
. The squelch is particularly effective for FM. It is also
available for other modes.
. 12 to 1 ofclock position is recommended for any setting
of the [RF/SQL] control.
. The control can be set as eAutof (RF gain control in SSB,
CW and RTTY; squelch control in AM and FM) or
squelch control (RF gain is fixed at maximum) in set
mode as follows. (p. 82)
MODE
RF GAIN
SSB, CW
RTTY
AM, FM
. When setting as RF gain/squelch control
Squelch is
open.
RF gain
adjustable
range
3.5 2 1.8 1 7 3
F-INP
10 4 18 6 14 5
21 7 24 8 28 9 SPLIT
GENE 144 ENT 50 0 A/B
TS MP-W MP-R
TX RX
LOCK XFC
F 5
FILTER
CALL LOCK/
SPCH MONITOR
SET MODE SETTING
SQL AUTO RF GAIN + SQL
SQL RF GAIN + SQL
SQL SQL RF GAIN + SQL
Noise squelch (FM mode)
Recommended level
Maximum
RF gain
S-meter
squelch
PANEL DESCRIPTION 1
•When functioning as RF gain control !0 CW PITCH CONTROL [CW PITCH] (p. 28)
(Squelch is fixed open; SSB, CW, RTTY only) Shifts the received CW audio pitch and monitored
CW audio pitch without changing the operating frequency.
Maximum
RF gain • The pitch can be changed from 300 to 900 Hz in approx.
25 Hz steps. Adjustable
range Increases Decreases
CW PITCH
Minimum RF gain
!1 ELECTRONIC CW KEYER SPEED CONTROL
[KEY SPEED] (p. 28) •When functioning as squelch control
(RF gain is fixed at maximum.) Adjusts the internal electronic CW keyer’s speed.
• 6 wpm (min.) to 60 wpm (max.) can be set.
Noise squelch (FM mode)
Fast Slow Noise squelch
threshold
(FM mode) KEY SPEED
S-meter squelch
threshold
!2 AUTO NOTCH/MANUAL NOTCH SWITCH
[A/NOTCH] (p. 53)
S-meter
squelch
Squelch is
open.
Toggles the notch function between manual and automatic
when pushed.
Deep Shallow • “NOTCH” appears when manual; “A NOTCH” appears
when automatic notch is selected.
!3 NOTCH CONTROL [NOTCH] (outer control; p. 53)
While rotating the RF gain control, noise may be
heard. This comes from the DSP unit and does not
indicate an equipment malfunction. Adjusts the notch filter frequency to remove an interfering
signal.
u MIC GAIN CONTROL [MIC GAIN] NOTCH NR
Adjusts microphone input gain.
• The transmit audio tone in SSB, AM and FM modes can High frequency Low frequency
be adjusted in tone control set mode. (p. 89)
.How to set the microphone gain.
!4 ANTENNA SELECTOR SWITCH [ANT] (p. 75)
Switches the antenna connector selection between
ANT1 and ANT2 when pushed.
Set the [MIC] control so that the ALC meter sometimes
swings during normal voice transmission in SSB mode.
Make sure that voice peak readings do not exceed the ALC
range brackets on the meter.
!5 NOISE REDUCTION LEVEL CONTROL [NR]
Recommended level for
an Icom microphone (inner control; p. 53)
Adjusts the noise reduction level when the noise reduction
is in use. Set for maximum readability. Increases Decreases
NOTCH NR
MIC GAIN
Decreases Increases
i AF CONTROL [AF] (inner control)
Varies the audio output level from the speaker. OFF
RF/SQL AF
Increases Decreases !6 ANTENNA TUNER SWITCH [TUNER] (pgs. 76, 77)
.Turns the antenna tuner ON and OFF (bypass)
when pushed momentarily.
No audio output Max. audio output
.Starts to tune the antenna manually when
pushed for 1 sec.
o RF POWER CONTROL [RF PWR]
Continuously varies the RF output power from min-
•When the tuner cannot tune the antenna, the tuning
circuit is bypassed automatically after 20 sec.
imum (less than 5 W*) to maximum (100 W*).
* AM mode: less than 5 W to 40 W !7 NOISE REDUCTION SWITCH [NR] (p. 53)
Increases Decreases
Switches the noise reduction ON and OFF.
• “NR” appears while the noise reduction is activated.
RF PWR
2
1 PANEL DESCRIPTION
!8 MULTI-FUNCTION SWITCHES [F1].[F5]
.Toggles between menu 1 (M1) and menu 2 (M2).
@3
. Front panel (continued)
T
Y
RF PWR
!8
!9 MENU SWITCH [MENU]
@0 MODE SWITCHES
is installed. (p. 90)
i746PRO
ANT TUNER
NOTCH NR
A/NOTCH NR
AF RF/SQL
MIC GAIN
SSB
CW/RTTY
AM/FM
HF/VHF TRANSCEIVER
F 2 F 3 F 4 F 1
MENU SSB CW/RTTY
CW PITCH KEY SPEED P.AMP/ATT NB
@2 !9 @0 @1
.Push to select the function indicated in the LCD
display above these switches. (p. 11)
.Functions vary depending on the operating mode.
.Push to input a character for memory keyer programming
or memory name. (pgs. 31, 67)
Push to change the set of functions assigned to the
multi-function switches.
Selects the desired mode. (p. 23)
. Announces the selected mode when an optional UT-102
.Selects USB and LSB mode alternately.
.Selects SSB data mode (USB-D, LSB-D)
when pushed for 1 sec. in SSB mode.
.Selects CW and RTTY mode alternately.
.Switches CW and CW-R (CW reverse)
mode when pushed for 1 sec. in CW
mode.
.Switches RTTY and RTTY-R (RTTY reverse)
mode when pushed for 1 sec. in
RTTY mode.
.Selects AM and FM mode alternately.
.Selects AM/FM data mode (AM-D, FM-D)
when pushed for 1 sec. in AM/FM mode.
@4
3
F 5
FILTER AM/FM
VOX/BK-IN MONITOR
@5 @6
TWIN PBT
3.5 2 1.8 1 7 3
F-INP
10 4 18 6 14 5
21 7 24 8 28 9 SPLIT
MW PBTC
GENE 144 ENT 50 0 A/B
V/M M-CL
M-CH TS MP-W MP-R
#7
#6
#5
#4
TX RX
LOCK XFC #3
RIT CLEAR ¡ÓTX
RIT/¡ÓTX
#2
#1
#0
CALL LOCK/
SPCH
@7
ON and OFF.
@9
@1 PREAMP/ATTENUATOR SWITCH [P.AMP/ATT]
(p. 48)
.Push momentarily to toggle between preamp-1
and preamp-2.
. ¡°P.AMP1¡± activates for HF all bands.
. ¡°P.AMP2¡± activates high-gain preamp for 24 MHz
band and above.
.Push for 1 sec. to toggle the attenuator function
The preamp amplifies received signals in the front end circuit
to improve the S/N ratio and sensitivity. Select ¡°P.AMP1¡±
or ¡°P.AMP2¡± when receiving weak signals.
The attenuator prevents a desired signal from distorting
when very strong signals are near the desired frequency, or
when very strong electric fields, such as from a broadcasting
station, are near your location.
@2 NOISE BLANKER SWITCH [NB] (p. 51)
.Switches the noise blanker ON and OFF when
pushed. The noise blanker reduces pulse-type
noise such as that generated by automobile ignition
systems. This function cannot be used for
FM, or non-pulse-type noise.
. ¡°NB¡± appears while the noise blanker is activated.
.Enters the noise blanker level set mode when
@8
.What is the preamp?
.What is the attenuator?
pushed for 1 sec.
@3 VOX/BREAK-IN SWITCH [VOX/BK-IN]
.In SSB, AM and FM modes, push momentarily to
turn the VOX function ON and OFF (p. 55); push
for 1 sec. to enter VOX set mode (p. 55).
.In CW mode, push momentarily to turn the semi
break-in, full break-in or break-in OFF (p. 56);
push for 1 sec. to enter break-in set mode (p. 56).
.What is the VOX function?
The VOX function (voice operated transmission) starts transmission
without pushing the transmit switch or PTT switch
when you speak into the microphone; then, automatically returns
to receive when you stop speaking.
.What is the break-in function?
Full break-in (QSK) activates the receiver between transmitted
dots and dashes. This is useful when operating in nets,
or during DX pileups and during contests, when gfast exchangesh
are common.
@4 MONITOR SWITCH [MONITOR] (p. 57)
.Monitors your transmitted signal.
.Enters monitor set mode when pushed for 1 sec.
@5 FILTER SWITCH [FILTER] (p. 50)
.Selects one of 3 IF filter settings.
.Enters the filter set mode when pushed for 1 sec.
@6 CALL SWITCH [CALL] (p. 64)
Selects the call channel when pushed momentarily.
@7 TUNING DIAL (p. 21)
Changes the displayed frequency, selects set mode
items, etc.
@8 LOCK/SPEECH SWITCH [LOCK/SPCH]
.Push momentarily to toggle the dial lock function
ON and OFF. (p. 53)
.Pushing for 1 sec. announces the selected readout
frequency and S-meter indication when an
optional UT-102 is installed. (p. 90)
@9 RIT/ÝTX CONTROL [RIT/ÝTX] (pgs. 48, 57)
Shifts the receive and/or transmit frequency without
changing the transmit and/or receive frequency
while the RIT and/or ÝTX functions are ON.
. Rotate the control clockwise to increase the frequency,
or rotate the control counterclockwise to decrease the
frequency.
. The shift frequency range is }9.99 kHz in 10 Hz steps.
RIT/ÝTX
High shift Low shift
PANEL DESCRIPTION 1
#0 RIT SWITCH [RIT] (p. 48)
.Turns the RIT function ON and OFF when pushed.
. Use the [RIT/ÝTX] control to vary the RIT frequency.
.Adds the RIT shift frequency to the operating frequency
when pushed for 1 sec.
.What is the RIT function?
The RIT (Receiver Incremental Tuning) shifts the receive frequency
without shifting the transmit frequency.
This is useful for fine tuning stations calling you on an off-frequency
or when you prefer to listen to slightly differentsounding
voice characteristics, etc.
#1 CLEAR SWITCH [CLEAR] (pgs. 48, 57)
Clears the RIT/ÝTX shift frequency when pushed
for 1 sec.
. Can be cleared instantly when [CLEAR] is pushed if the
Quick RIT Clear is set to ON (p. 86).
#2 ÝTX SWITCH [ÝTX] (p. 57)
.Turns the ÝTX function ON and OFF when
pushed.
. Use the [RIT/ÝTX] control to vary the ÝTX frequency.
.Adds the ÝTX shift frequency to the operating
frequency when pushed for 1 sec.
.What is the ÝTX function?
The ÝTX shifts the transmit frequency without shifting the receive
frequency. This is useful for simple split frequency operation
in CW, etc.
#3 MEMORY CHANNEL SELECTOR [M-CH] (p. 62)
Select a memory channel.
. Rotate clockwise to increase the memory channel; rotate
counterclockwise to decrease the memory channel.
#4 VFO/MEMORY SWITCH [VFO/MEMO]
.Switches the selected readout operating mode
between the VFO mode and memory mode when
pushed. (pgs. 20, 62)
.Transfers the memory contents to VFO when
pushed for 1 sec. (p. 65)
#5 MEMORY CLEAR SWITCH [M-CL] (p. 63)
Clears the selected readout memory channel contents
when pushed for 1 sec. in memory mode.
. The channel becomes a blank channel.
. This switch does not function in VFO mode.
#6 MEMORY WRITE SWITCH [MW] (p. 63)
Stores the selected readout frequency and operating
mode into the displayed memory channel when
pushed for 1 sec.
.This function is available both in VFO and memory
modes.
#7 PBT CLEAR SWITCH [PBTC] (p. 52)
Clears the PBT settings when pushed for 1 sec.
4
1 PANEL DESCRIPTION
. Front panel (continued)
F 1
MENU SSB
CW PITCH RF PWR KEY SPEED P.AMP/ATT
HF/VHF TRANSCEIVER
F 2 F 3 F 4
%2
CW/RTTY
NB
i746PRO
ANT NER
NOTCH NR
A/NOTCH NR
AF RF/SQL
MIC GAIN
#8 TRANSMIT FREQUENCY CHECK SWITCH [XFC]
(pgs. 45, 48)
Monitors the transmit frequency when pushed and
held.
. While pushing this switch, the transmit frequency can be
changed with the tuning dial, keypad or memo pad.
. When the split lock function is turned ON, pushing [XFC]
cancels the dial lock function. (p. 60)
#9 MEMO PAD-WRITE SWITCH [MP-W] (p. 68)
Programs the selected readout frequency and operating
mode into a memo pad.
. The 5 most recent entries remain in memo pads.
. The transmit frequency is programmed when pushed together
with [XFC].
.The memo pad capacity can be expanded from 5 to 10
in set mode for your convenience. (p. 85)
$0 TRANSMIT INDICATOR [TX]
Lights red while transmitting.
$1 MEMO PAD-READ SWITCH [MP-R] (p. 68)
Each push calls up a frequency and operating
mode in a memo pad. The 5 (or 10) most recently
programmed frequencies and operating modes can
be recalled, starting from the most recent.
.The memo pad capacity can be expanded from 5 to 10
in set mode for your convenience. (p. 85)
$2 RECEIVE INDICATOR [RX]
Lights green while receiving a signal and when the
squelch is open.
$3 LOCK INDICATOR [LOCK] (p. 53)
Lights when the dial lock function is activated.
AM/FM
VOX/BK-IN
5
F 5
FILTER
CALL MONITOR
TWIN PBT
1.8 1 7 3
$7 10 4 18 6
$6
MW
%1
3.5 2
14 5
21 7 24 8 28 9
50 0 GENE 144 ENT $5 M-CL
M-CH MP-W MP-R $4
TX
XFC
CLEAR ÝTX
RIT/ÝTX
%0 $9 $8
F-INP
SPLIT
PBTC
A/B
V/M
TS
RX
LOCK
RIT
LOCK/
SPCH
erating mode of the two VFOfs.
$3
$2
$1
$0
#9
#8
$4 QUICK TUNING SWITCH [TS] (p. 21)
.Turns the quick tuning step ON and OFF.
. While the quick tuning indicator is displayed, the frequency
can be changed in programmed kHz steps.
.0.1, 1, 5, 9, 10, 12.5, 20 and 25 kHz quick tuning
steps are available.
Quick tuning indicator
.While the quick tuning step is OFF, turns the 1 Hz
step ON and OFF when pushed for 1 sec.
.1 Hz indication appears, and the frequency can be
changed in 1 Hz steps.
.While the quick tuning step is ON, enters the
quick tuning step set mode when pushed for
1 sec.
$5 VFO SELECT SWITCH [A/B] (p. 20)
.Push to toggle between VFO A and VFO B.
.Push for 1 sec. to equalize the frequency and op-
$6 SPLIT SWITCH [SPLIT]
.Turns the split function ON and OFF when
pushed.(p. 59)
.Turns the quick split function ON, when pushed
for 1 sec. (p. 60)
•The offset frequency is shifted from the displayed frequency.
• The quick split function can be turned OFF using set
mode. (p. 83)
.Turns the split function ON and sets the transmit
frequency after inputting an offset frequency with
the keypad (±4 MHz in 1 kHz steps; p. 59).
$7 PASSBAND TUNING CONTROLS [TWIN PBT]
Adjust the receiver’s “passband width” of the DSP
filter. (p. 52)
• Passband width and shift frequency are displayed in the
multi-function switch indicator.
• Push [PBTC] for 1 sec. to clear the settings when not in
use.
•Variable range is set to half of the IF filter passband
width. 25 Hz steps and 50 Hz steps are available.
• These controls function as an IF shift control while in AM
mode and when the RTTY filter is turned ON. Only the
inner control may function in this case.
.What is the PBT control?
General PBT function electronically narrows the IF passband
width to reject interference. This transceiver uses the DSP
circuit for the PBT function.
TWIN PBT
PBT1
PBT2
TWIN PBT TWIN PBT TWIN PBT
+ –
High cut Center Low cut
$8 SPLIT INDICATOR (p. 59)
Lights during split operation.
$9 FREQUENCY INPUT SWITCH [F-INP] (p. 22)
Push to toggle keypad input between frequency and
band.
• The frequency input indicator lights when frequency
input is selected for the keypad.
%0 FREQUENCY INPUT INDICATOR (p. 22)
Lights when frequency input from the keypad is enabled.
PANEL DESCRIPTION 1
%1 KEYPAD
.Pushing a key selects the operating band.
•[GENE • ] selects the general coverage band.
.Pushing the same key 2 or 3 times calls up other
stacked frequencies and modes in the band.
(p. 19)
•Icom’s triple band stacking register memorizes 3 frequencies
in each band.
.After pushing [F-INP], enter a keyed frequency.
Pushing [144 ENT] is necessary at the end.
(p. 22)
• e.g. to enter 14.195 MHz, push [F-INP] [1.8 1] [10 4]
[GENE • ] [1.8 1] [28 9] [14 5] [144 ENT].
%2 LCD FUNCTION DISPLAY
(See pgs. 9, 10 for details.)
Shows the operating frequency, function switch
menus, band scope screen, memory name screen,
set mode settings, etc.
6
1 PANEL DESCRIPTION
q w e r
!1 !4 !3
Rear panel view
. Rear panel
!5
. See p. 8 for connector information.
. Max. control level: 16 V DC/0.5 A
!2
q DC POWER SOCKET [DC 13.8V] (pgs. 14, 16)
Accepts 13.8 V DC through the supplied DC power
cable (OPC-025D).
w ANTENNA CONNECTOR [ANT 144MHz]
e ANTENNA CONNECTOR 2 [ANT2]
r ANTENNA CONNECTOR 1 [ANT1]
(pgs. 14, 15, 17, 75)
Accepts a 50 §Ù antenna with a PL-259 connector.
.[ANT 144MHz] for 144 MHz (2 m) band only; [ANT1] and
[ANT2] for both HF and 50 MHz (6 m) bands antennas.
When using an optional AH-4 HF/50 MHz AUTOMATIC
ANTENNA TUNER, connect it to the [ANT1]
connector. The internal antenna tuner activates
for [ANT2] and deactivates for [ANT1] when connecting
the AH-4.
t DATA SOCKET [DATA] (pgs. 15, 78)
Connects a TNC (Terminal Node Controller), etc. for
data communications.
y EXTERNAL SPEAKER JACK [EXT SP] (pgs. 15, 101)
Accepts a 4.8 §Ù speaker.
u CI-V REMOTE CONTROL JACK [REMOTE] (p. 95)
.Designed for use with a personal computer for remote
control of the transceiver functions.
.Used for transceive operation with another Icom
CI-V transceiver or receiver.
i SEND CONTROL JACK [SEND] (p. 17)
Goes to ground while transmitting to control external
equipment such as a linear amplifier.
CAUTION: Be sure the linear amplifiers keying circuit
control voltage is compatible to the IC-746PRO,
7
!0 u yt o i
before connecting to [SEND].
o ALC INPUT JACK [ALC] (p. 17)
Connects to the ALC output jack of a non-Icom linear
amplifier.
!0 ACCESSORY SOCKET 2 [ACC(2)]
!1 ACCESSORY SOCKET 1 [ACC(1)]
Enables connection of external equipment such as
a linear amplifier, an automatic antenna selector/
tuner, TNC for data communications, etc.
. See p. 8 for socket information.
!2 STRAIGHT KEY JACK [KEY] (p. 14)
Accepts a straight key or external electronic keyer
with 1.4 inch standard plug.
. [ELEC-KEY] on the front panel can be used for a straight
key or external electronic keyer. Deactivate the internal
electronic keyer in keyer set mode. (p. 34)
(+)
(_)
!3 TUNER CONTROL SOCKET [TUNER]
(pgs. 15, 77)
Accepts the control cable from an optional AH-4
HF/50 MHz AUTOMATIC ANTENNA TUNER.
If you use an external electronic keyer, make
sure the voltage retained by the keyer is less
than 0.4 V when the key is ON.
!4 CALIBRATION POT [CAL] (p. 94)
This is used for frequency calibration.
. The transceiver has been adjusted and calibrated thoroughly
at the factory. Under normal circumstances, the
frequency does not need to be re-calibrated.
!5 GROUND TERMINAL [GND] (pgs. 13, 14)
Connect this terminal to a ground to prevent electrical
shocks, TVI, BCI and other problems.
PANEL DESCRIPTION 1
DESCRIPTION
DATA IN Input terminal for data transmit. (1200 bps: AFSK/9600 bps: G3RUH, GMSK)
GND Common ground for DATA IN, DATA OUT and AF OUT.
PTT P PTT terminal for packet operation. Connect ground to transmit data.
DATA OUT Data out terminal for 9600 bps operation only.
AF OUT Data out terminal for 1200 bps operation only.
DDATA SOCKET
PIN No. NAME DATA
1 2
3 4
1
2
3
4
5
5 6
Rear panel view 6 P SQL
Squelch out terminal. Becomes high (+8 V) when the transceiver receives a signal
which opens the squelch.
.To avoid unnecessary TNC transmission, connect squelch to the TNC to inhibit transmission
when receiving signals.
. Keep audio output at a normal level, otherwise a ¡°P SQL¡± signal will not be output.
SPECIFICATIONS DESCRIPTION
RTTY Controls RTTY keying
: More than 2.4 V
: Less than 0.6 V
: Less than 2 mA
¡°High¡± level
¡°Low¡± level
Output current
GND Connects to ground. Connected in parallel with ACC(2) pin 2.
Ground level : .0.5 V to 0.8 V
Output current : Less than 20 mA
Input current (Tx) : Less than 200 mA
Connected in parallel with ACC(2) pin 3.
MOD Modulator input.
Connects to a modulator.
: 10 k§Ù
: Approx. 100 mV rms
Input impedance
Input level
Output impedance : 4.7 k§Ù
Output level : 100.300 mV rms
AF detector output.
AF Fixed, regardless of [AF] position in
default settings. (see notes below)
SQL open SQLS Squelch output.
Goes to ground when squelch opens. SQL closed
: Less than 0.3 V/5 mA
: More than 6.0 V/100 ¥ìA
Output current 13.8 V 13.8 V output when power is ON. : Max. 1 A
Connected in parallel with ACC(2) pin 7.
ALC ALC voltage input.
Control voltage : .4 V to 0 V
Input impedance : More than 10 k§Ù
Connected in parallel with ACC(2) pin 5.
SPECIFICATIONS DESCRIPTION
8 V Regulated 8 V output. : 8 V ¡¾0.3 V
: Less than 10 mA
GND
Output voltage
Output current
Same as ACC(1) pin 2.
Same as ACC(1) pin 3.
: 0 to 8.0 V Output voltage BAND Band voltage output.
(Varies with amateur band)
Same as ACC (1) pin 8. ALC
Input/output pin (144 MHz only) Ground level
VSEND Goes to ground when transmitting. Output current
When grounded, transmits.
DACC SOCKETS
PIN No. NAME ACC (1)
1
2
Input/output pin. (HF/50 MHz only)
3 HSEND Goes to ground when transmitting.
When grounded, transmits.
2
5
4
4
1 3 8
6 7
5
Rear panel view
6
7
8
PIN No. NAME ACC (2)
1
2
3 HSEND
2
5 4 4
1 3
6 7
Rear panel view
5
6
7
: .0.5 V to +0.8 V
: Less than 20 mA
Input current (Tx) : Less than 200 mA
Same as ACC(1) pin 7. 13.8 V
8
1 PANEL DESCRIPTION
!3 !4
. LCD display
q
w
e
r
t
q FREQUENCY READOUTS
Shows the operating frequency.
w MULTI-FUNCTION METER INDICATION
.Shows receiving signal strength, etc. during receive.
.Shows transmit output power, ALC and SWR during
transmit.
e VOX INDICATOR (p. 55)
Appears when the VOX function is activated.
r MICROPHONE COMPRESSOR INDICATOR (p. 58)
Appears when the microphone compressor is activated.
t MULTI-FUNCTION SWITCH INDICATOR (p. 11)
Indicates the functions assigned to the multi-function
switches ([F1]–[F5]).
y DSP FILTER INDICATOR (p. 50)
Shows the selected IF filter.
u MEMORY CHANNEL READOUTS (p. 62)
Shows the selected memory channel.
i SELECT MEMORY CHANNEL INDICATOR (p. 72)
Appears when the selected memory channel is set
as a select memory channel.
o BLANK MEMORY INDICATOR (p. 62)
Appears when the selected memory channel is
blank.
9
!0
o
i
u
!1
!2 MODE INDICATORS (p. 23)
!3 ANTENNA INDICATOR (p. 75)
!2
is selected.
y
!0 1/4 TUNING DIAL SPEED INDICATOR (p. 21)
Appears when the tuning dial speed is set so that
one rotation is equal to 1/4 of the normal rotation.
!1 VOICE SQUELCH CONTROL INDICATOR (p. 54)
Appears during VSC (Voice Squelch Control) function
is activated.
Shows the selected operating mode.
• “D” appears when SSB data, AM data or FM data mode
Indicates which antenna connector is used for
HF/50 MHz.
!4 ANTENNA TUNER INDICATORS (pgs. 76, 77)
.“TUNE” appears when the antenna tuner is ON;
“TUNE” appears and flashes during tuning.
.“EXT” appears when the optional AH-4 external
antenna tuner is connected to [ANT1].
. LCD display (continued)
!5
!6
!7
!8
!9
@0
!5 BREAK-IN INDICATORS (p. 56)
.¡°FBK-IN¡± appears when the full break-in function
is activated.
.¡°BK-IN¡± appears when the semi break-in function
is activated.
!6 MONITOR INDICATOR (p. 57)
Appears when the monitor function is activated.
!7 PREAMP INDICATORS (p. 48)
Appears when the preamp is activated.
!8 ATTENUATOR INDICATOR (p. 48)
Appears when the attenuator is activated.
!9 AGC INDICATORS (p. 49)
Shows the selected AGC time constant.
. ¡°F¡± for AGC fast; ¡°M¡± for AGC middle; ¡°S¡± for AGC
slow; ¡°-OFF¡± for AGC OFF.
@0 NOISE BLANKER INDICATOR (p. 51)
Appears when the noise blanker is activated.
@1 DTCS INDICATOR (p. 43)
Appears during DTCS operation.
@2 TONE SQUELCH INDICATORS
.¡°T¡± appears when the repeater tone is activated.
(p. 44)
.¡°TSQL¡± appears during tone squelch operation.
(p. 42)
@3 DUPLEX INDICATOR (p. 44)
¡°DUP.¡± or ¡°DUP+¡± appears during repeater operation.
PANEL DESCRIPTION 1
@8
@7
@6
@5
@4
@3
@9
@5 NOTCH INDICATORS (p. 53)
@6 SPLIT INDICATOR (pgs. 59, 60)
Appears during split operation.
@7 MEMORY INDICATOR (p. 62)
Appears during memory mode.
@8 VFO INDICATORS (p. 20)
@2
@1
@4 NOISE REDUCTION INDICATOR (p. 53)
Appears when the noise reduction is activated.
.¡°NOTCH¡± appears when the manual notch function
is activated.
.¡°ANOTCH¡± appears when the automatic notch
function is activated.
Indicates whether VFO A or VFO B is selected.
@9 RIT/¡ÓTX INDICATORS (pgs. 48, 57)
Appears during RIT or ¡ÓTX operation and indicates
the frequency offset.
10
1 PANEL DESCRIPTION
SCP
F 5
SCP
F 5
SCP
F 5
1/4 SCP
F 5
SCP
F 5
CMP
F 2 F 3 F 4
. Multi function switches
TBW
F 2 F 3 F 4
CMP
During SSB data operation
1/4
F 2 F 3 F 4
DUP
During CW operation
1/4 KEY
F 2 F 3 F 4
DUP
During RTTY operation
RTY
F 2 F 3 F 4
DUP
During AM operation
DUP
During FM operation
DUP TON
F 2 F 3 F 4
peater function ON/OFF.
DM1 FUNCTIONS
During SSB operation
DUP AGC
F 1
AGC
F 1
AGC
F 1
AGC
F 1
AGC
F 1
AGC
F 1
AGC (p. 49)
AGC
F 1
DUPLEX (p. 44)
DUP
F 2
SPEECH COMPRESSOR (p. 58)
CMP
F 3
SCP
F 5
.Push momentarily to change the time
constant of the AGC circuit.
.Push for 1 sec. to enter to the AGC set
mode.
.Push momentarily to select the duplex direction
or turn the function OFF.
• “DUP–” or “DUP+” indicator appears during
duplex operation.
.Push for 1 sec. to turn the one-touch re-
.Push momentarily to turn the speech
compressor function ON/OFF.
• “COMP” indicator appears when the speech
compressor is ON.
.Push for 1 sec. to enter to the compres-
CMP
sor set mode.
11
1/4 TUNING FUNCTION (p. 21)
Push to turn the 1/4 tuning function
ON/OFF.
• “ ” indicator appears when the 1/4 tuning
function is ON.
1/4
F 3
TRANSMISSION BANDWIDTH (p. 58)
Push to select the transmission bandwidth.
•Bandwidth is selectable from narrow, middle
and wide.
TBW
F 4
MEMORY KEYER MENU (p. 29)
Push to select the memory keyer or keyer
send menu, depending on the KEYER
1st Menu setting in the set mode (p. 86).
KEY
F 4
RTTY MENU (p. 36)
Push to select the RTTY menu. RTY
F 4
BAND SCOPE FUNCTION (p. 47)
Push to select the band scope screen. SCP
F 5
DM2 FUNCTIONS
SWR SCN
F 1
MEM
SCAN MENU (p. 70)
TCN
F 2 F 3 F 4
Push to select the scan menu. SCN
F 1
MEMORY NAME MENU (p. 67)
MEM
F 2
SWR GRAPH FUNCTION (p. 61)
SWR
F 3
TONE CONTROL SET MODE (p. 89)
TCN
F 4
VSC FUNCTION (p. 54)
VSC
F 5
Push to select the memory name screen.
Push to indicate the SWR graph screen.
Push to enter the audio tone set mode.
Push to turn the VSC (Voice Squelch Control)
function ON and OFF.
VSC
F 5
PANEL DESCRIPTION 1
. Microphone (HM-36)
q
w PTT SWITCH
Push and hold to transmit; release to receive.
w
q UP/DOWN SWITCHES [UP]/[DN]
Change the selected readout frequency or memory
channel.
.Continuous pushing changes the frequency or memory
channel number continuously.
. While pushing [XFC], the transmit readout frequency can
be controlled while in spilt frequency operation.
. The [UP]/[DN] switch can simulate a key paddle. Preset
in the keyer set mode. (p. 34)
DESCRIPTION FUNCTION
[MIC]
Pin No.
w
e
Max. 10 mA
Ground
Ground through 470 .
gLowh level
gHighh level
+8 V DC output
Frequency up
Frequency down
Squelch open
Squelch closed
.MICROPHONE CONNECTOR
(Front panel view)
i Main readout AF output
(varies with [AF]/[BAL])
q Microphone input u GND
(Microphone ground)
y GND (PTT ground) w +8 V DC output
e Frequency up/down t PTT
r Main readout squelch switch
r
CAUTION: DO NOT short pin 2 to ground as this
can damage the internal 8 V regulator.
NOTE: DC voltage is applied to pin 1 for microphone
operation. Take care when using a non-Icom
microphone.
MICROPHONE CABLE MICROPHONE PLUG
+ 2k
4700p
+
0.33ƒÊ
4700p
u
y i
q
w
e UP DOWN
r
t
470
.HM-36 SCHEMATIC DIAGRAM
MICROPHONE
10ƒÊ
MIC
ELEMENT
PTT RECEIVE
TRANSMIT
12
2 INSTALLATION AND CONNECTIONS
. Unpacking
After unpacking, immediately report any damage to the
delivering carrier or dealer. Keep the shipping cartons.
For a description and a diagram of accessory equipment
included with the IC-746PRO, see ¡®Supplied accessories¡¯
on p. ii of this manual.
. Selecting a location
Select a location for the transceiver that allows adequate
air circulation, free from extreme heat, cold, or
vibrations, and away from TV sets, TV antenna elements,
radios and other electromagnetic sources.
The base of the transceiver has an adjustable stand
for desktop use. Set the stand to one of two angles depending
on your operating conditions.
. Antenna connection
For radio communications, the antenna is of critical importance,
along with output power and sensitivity. Select
antenna(s), such as a well-matched 50 §Ù antenna,
and feedline. 1.5:1 or better of Voltage Standing Wave
Ratio (VSWR) is recommended for your desired band.
Of course, the transmission line should be a coaxial
cable.
When using 1 antenna, use the [ANT1] connector.
CAUTION: Protect your transceiver from lightning
by using a lightning arrestor.
PL-259 CONNECTOR INSTALLATION EXAMPLE
q
w
e
r
Antenna SWR
Each antenna is tuned for a specified frequency
range and SWR may be increased out-of-range.
When the SWR is higher than approx. 2.0:1, the
transceiver¡¯s power drops to protect the final transistor.
In this case, an antenna tuner is useful to match
the transceiver and antenna. Low SWR allows full
power for transmitting even when using the antenna
tuner. The IC-746PRO has an SWR meter to monitor
the antenna SWR continuously.
30 mm Slide the coupling ring
down. Strip the cable
jacket and soft solder.
10 mm (soft solder) Coupling ring
10 mm Soft
solder
1.2 mm
Strip the cable as
shown at left. Soft solder
the center conductor.
solder solder
Slide the connector
body on and solder it.
Screw the coupling
ring onto the
connector body.
30 mm . 9.8 in 10 mm . 3.8 in 1.2 mm . 1.16 in
. Grounding
To prevent electrical shock, television interference
(TVI), broadcast interference (BCI) and other problems,
ground the transceiver through the GROUND
terminal on the rear panel.
For best results, connect a heavy gauge wire or strap
to a long earth-sunk copper rod. Make the distance between
the [GND] terminal and ground as short as possible.
RWARNING: NEVER connect the [GND]
terminal to a gas or electric pipe, since the connection
could cause an explosion or electric shock.
13
POWER
TRANSMIT
PHONES
ELEC-KEY
MIC
. Required connections
(dot)
(com)
(dash)
PS-125
(Optional)
. Front panel
CW KEY
A straight key can be used
when the internal electronic
keyer is turned OFF in keyer
set mode. (p. 34)
.Rear panel
144 MHz ANTENNA (pgs. 13, 75)
DC POWER SUPPLY
GROUND (p. 13)
MICROPHONES (p. 101)
Connect a VHF
(60.144 MHz)
antenna;
impedance: 50 §Ù.
Use the heaviest gauge wire or
strap available and make the
connection as short as possible.
Grounding prevents electrical
shocks, TVI and other problems.
i746PRO
ANT TUNER
NR NOTCH
A/NOTCH NR
RF/SQL AF
MIC GAIN
HM-36
INSTALLATION AND CONNECTIONS 2
TWIN PBT HF/VHF TRANSCEIVER
1.8 1 3.5 2 7 3
F-INP
10 4 14 5 18 6
21 7 24 8 28 9 SPLIT
MW PBTC
GENE 50 144 ENT 0 A/B
V/M M-CL
M-CH MP-R MP-W TS
XFC
CLEAR ¡ÓTX RIT
RIT/¡ÓTX
F 5 F 4 F 3 F 2 F 1
MENU SSB FILTER AM/FM CW/RTTY
CALL VOX/BK-IN CW PITCH KEY SPEED RF PWR P.AMP/ATT NB
LOCK/
SPCH MONITOR
SM-20
(optional)
ANTENNA 1, 2 (pgs. 13, 75)
[Example]: ANT1 for 1.8.18 MHz bands
ANT2 for 21.50 MHz bands
STRAIGHT KEY
(+)
(_)
14
2 INSTALLATION AND CONNECTIONS
When using the AH-4, it must
be connected to the [ANT1]
connector.
i746PRO
ANT TUNER
NOTCH NR
A/NOTCH NR
AF RF/SQL
MIC GAIN
The AFSK modulation signal
can be input from [MIC]. (p. 78)
AH-4 (p. 77)
. Advanced connections
. Front panel
HEADPHONES
.Rear panel
AH-2b
ACC SOCKETS (pgs. 8, 78)
[REMOTE] (p. 95)
Used for computer control and transceive operation.
POWER
TRANSMIT
PHONES
ELEC-KEY
MIC
MIC
15
HF/VHF TRANSCEIVER
F 2 F 3 F 4 F 1
MENU CW/RTTY SSB
CW PITCH RF PWR NB KEY SPEED P.AMP/ATT
TWIN PBT
3.5 2 1.8 1 7 3
F-INP
10 4 18 6 14 5
21 7 24 8 28 9 SPLIT
MW PBTC
GENE 144 ENT 50 0 A/B
V/M M-CL
M-CH TS MP-W MP-R
TX RX
LOCK XFC
RIT CLEAR ÝTX
RIT/ÝTX
F 5
FILTER AM/FM
CALL LOCK/
SPCH VOX/BK-IN MONITOR
ANTENNA 1, 2 (p. 17)
Connects a linear amplifier,
antenna selector, etc.
[SEND], [ALC] (p. 17)
Used for connecting a
non-Icom linear amplifier.
[DATA] (p. 78)
EXTERNAL SPEAKER (p. 101)
SP-21
(optional)
INSTALLATION AND CONNECTIONS
CAUTION: Before connecting the DC power
cable, check the following important items. Make
sure:
•The [POWER] switch is OFF.
•Output voltage of the power source is 12–15 V
when you use a non-Icom power supply.
• DC power cable polarity is correct.
: positive + terminal
: negative _ terminal
Red
Black
DC power
socket
to DC power
socket
. Power supply connections
Use an optional DC power supply with a 25 A capacity
and above when operating the transceiver with AC
power. Refer to the diagrams below.
CONNECTING PS-125 DC POWER SUPPLY
PS-125
Connect to an AC outlet
using the supplied AC cable.
DC power cable
CONNECTING A DC POWER SUPPLY
AC outlet A DC power supply
13.8 V; at least 23 A
Black Red
_
Supplied
DC power cable
AC cable
+
30 A fuses
CONNECTING A VEHICLE BATTERY
Grommet
NEVER connect to
a 24 V battery.
_ black
12 V
battery
Supplied
DC power cable
NEVER connect to a battery without supplied DC
fuses, otherwise a fire hazard may occur.
+ red
2
Transceiver
Transceiver
NOTE: Use terminals for
the cable connections.
Crimp
Solder
16
2 INSTALLATION AND CONNECTIONS
. Linear amplifier connections
CONNECTING THE IC-PW1
To an
antenna ACC(1)
REMOTE ANT
IC-PW1
AC outlet
(Non-European versions: 100.120/220.240 V
European version : 230 V)
Turn OFF the transceiver¡¯s antenna tuner while tuning the IC-PW1¡¯s tuner.
CONNECTING A NON-ICOM LINEAR AMPLIFIER
To an
antenna
RF OUTPUT RF INPUT
ALC
SEND
Non-Icom linear amplifier
Remote control cable (supplied with the IC-PW1)
ACC cable (supplied with the IC-PW1)
INPUT1
EXCITER
1 1&2
GND
50 §Ù coaxial cable
Transceiver
ALC
. External antenna tuner connections
CONNECTING THE AH-4
The AH-4 must be connected to [ANT1].
Coaxial cable (from AH-4)
ANT1 Transceiver
Control cable
AH-4
Ground
17
Use the [ANT1] connector when connecting a linear
amplifier.
Coaxial cable
(supplied with the IC-PW1)
Be sure to connect the cable
to the 7-pin ACC(2) jack.
GND
Transceiver Ground
ANT1
SEND
R WARNING:
Set the transceiver output power and linear ampli-
fier ALC output level referring to the linear amplifier
instruction manual. Be sure the linear amplifier keying
circuit control voltage is compatible with the IC-
746PRO, before connecting to [SEND] jack.