Icom IC-746PRO User Manual
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
PRECAUTIONS
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
WORD DEFINITION
RR
WARNING
CAUTION Equipment damage may occur.
NOTE
i
Personal injury, fire hazard or electric
shock may occur.
If disregarded, inconvenience only. No
risk or personal injury, fire or electric
shock.
R WARNING 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).
R WARNING HIGH VOLTAGE! NEVER attach an
antenna or internal antenna connector during transmission. This may result in an electrical shock or burn.
R NEVER apply AC to the [DC13.8V] jack on the trans-
ceiver rear panel. This could cause a fire or ruin the transceiver.
R 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.
R NEVER let metal, wire or other objects touch any in-
ternal 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 tem-
peratures 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 amplifier 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.
TABLE OF CONTENTS
qw
ert
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
■ 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
■ ∂TX 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
■ Voice squelch control function ...... 70
■ Scan set mode ............................. 70
■ Programmed scan/Fine programmed
scan .............................................. 71
■ Memory scan operation ................ 72
■ Select memory scan ..................... 72
■ ∂F scan operation and Fine ∂F 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
■ CR-338
VOICE SYNTHESIZER UNIT
HIGH STABILITY CRYSTAL UNIT
..................................................... 91
... 90
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
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.
ii
QUICK REFERENCE GUIDE
30 A fuses
AC cable
Transceiver
AC
outlet
A DC power
supply*
*13.8 V; at least 23 A
continuous
Black
_
Red
+
to DC power
socket
Supplied
DC power cable
PS-125
DC power
socket
Transceiver
DC power cable
Connect to an AC outlet using the supplied AC cable.
■ 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.
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.
R WARNING!: NEVER ground station equip-
ment or antennas to house gas lines. NEVER at-
tach ground lines to plastic (pvc) pipe.
DD
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.
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.
I
• 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.
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
30 mm
10 mm (soft solder)
10 mm
1–2 mm
solder solder
Soft
solder
Coupling ring
Slide the coupling ring
down. Strip the cable
jacket and soft solder.
Slide the connector
body on and solder it.
Screw the coupling
ring onto the
connector body.
Strip the cable as
shown at left. Soft solder the center conductor.
q
w
e
r
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 Ω.
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.
QUICK REFERENCE GUIDE
NOTE: There are many publications covering
proper lightning protection, check with your local
dealer for more information and recommendations.
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.
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 Ω feedline. The
purpose of the internal antenna tuner is to match the
impedance of your antenna system to as close to a
50 Ω load as possible. This ATU will not operate with
a long wire or ladder line (450 Ω or other balanced
feedlines). An external ATU such as the AH-4 would
be necessary for this kind of operation.
PL-259 CONNECTOR INSTALLATION EXAMPLE
30 mm ≈9⁄8 in 10 mm ≈3⁄8 in 1–2 mm ≈1⁄16 in
R WARNING: Although a mag mount antenna
works great on a vehicle, DO NOT use the IC746PRO 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
MICROPHONES
HM-36 SM-20
STRAIGHT KEY
(+)
(_)
CW KEY
A straight key can be used when the internal
electronic keyer is turned OFF in keyer set
mode. (p. 34)
(dot)
(com)
(dash)
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.
■ Operation
1. Voice
Microphones: Connect the microphone to the eightpin connector on the front of the radio.
If you do not see the particular item you are wanting
to connect, refer to the Advance Connections section
starting on page 15.
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.
III
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.
1
d. Computer Keying: Use a 6.35(d) mm (
⁄4″) mono
plug and connect to the back of the radio.
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.
3. Other convenient items
EXTERNAL SPEAKER
SP-21 (optional)
HEADPHONES
[POWER] [F-INP] [M-CL]
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.
QUICK REFERENCE GUIDE
External Speaker:
A 3.5(d) mm (1⁄8″) mono jack for operation with an ex-
ternal speaker. (Input impedance: 8 Ω/Max. input
power: 5 W)
■ 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 “On The Air” an enjoyable experience.
DD
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 vol-
ume: fully counter clockwise.
•[NR] : The noise reduction control: fully
counter clockwise.
•[MIC GAIN] : The mic gain: fully counter clock-
wise.
•[RF/SQL] : The control for the RF Gain and
Squelch circuits: 12 o’clock.
•[CW PITCH] : The control for the CW pitch:
12 o’clock.
•[KEY SPEED] : Internal CW Keyer Speed: fully
•[NOTCH] : Control for the manual notch:
counter clockwise
12 o’clock
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.
IV
QUICK REFERENCE GUIDE
GENE
50
0
21
7
24
8
28
9
14
5
10
4
18
6
3.5
2
1. 8
1
7
3
144
ENT
Either “1” or “2” appears.
*No indicator appears during
144 MHz operation.
AF RF/SQL
No audio output
Max. audio output
Decreases Increases
DD
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.
•Say you want to go to 20 meters or 14 MHz; you
would push the [145]. This will immediately change
the displayed operating frequency to the 20-meter
band. By pushing [145] again, frequency pre-sets
in the triple band stacking registers frequency can be
displayed. For more details on this system refer to
p. 19.
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.
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
DD
AGC DUP CMP TBW SCP
[NR] [NR]
Appears
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
QUICK REFERENCE GUIDE
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.
SSB
CW/RTTY
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.
NR NOTCH
Decreases
OFF
Noise reduction ON
Increases
b. Adjusting the Noise Reduction: The noise re-
duction is completely variable on how much of the
DSP Noise Reduction is used [NR] level control located just above the [NR] switch.
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
AGC DUP CMP TBW SCP
[A/NOTCH] [NOTCH]
Notch function indicators
NR NOTCH
Low frequency High frequency
BW
• Filter set mode indication
Shows the selected filter and passband width.
BW
• Indication while setting
While pushing [F1 BW], rotate the tuning dial to set
passband width.
Reverses Appears
AGC DUP CMP TBW SCP
[FILTER]
The selected filter width is indicated
for approx. 1 sec. when [FILTER] is
pushed.
Filter selection
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 atten-
uation 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.
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.
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.
VII
QUICK REFERENCE GUIDE
BW
• Filter set mode indication
Shows the selected filter and passband width.
BW
• Indication while PBT setting
Appears when passband is shifted.
*By pushing [PBTC] for 1 sec., the shifted value returns
to the default setting, and the “dot” disappears.
AGC DUP CMP TBW SCP
Passband width and shifting value are
indicated while [TWIN PBT] is operated.
[TWIN PBT] control
[PBTC]
Appears when PBT is used.
One of “1,” “2” or “3” is
displayed for selected filter
number indications.
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.
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.
PBT operation example
Center
IF center frequency
interference
Passband
desired signal
pass band
inteference
Passband
desired signal
IF shift
IF center freq.
interference
VIII
QUICK REFERENCE GUIDE
[F1 ≤]
Tuning dial[MENU]
[F2 ≥] [F4 TCN]
RX Bass
SSB
O
3
RX Treble
SSB
O
4
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 ±5dB.
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 ≤] or [F2 ≥] 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?”.
■ Ready to call CQ?
[NR]: Max. CCW [NOTCH]: Max. CCW
i746PRO
TUNER
POWER
TRANSMIT
[TRANSMIT]: OFF
PHONES
ELEC-KEY
[AF]: Max. CCW
MIC
[RF/SQL]: 12 o’clock
[MIC GAIN]: Max. CCW
[RF PWR]: Max. CCW [CW PITCH]: 12 o’clock
ANT
NR
NOTCH
/NOTCH
NR
A
AF
RF/SQL
F 1
MENU
MIC GAIN
RF PWR
CW PITCH
KEY SPEED
HF/VHF TRANSCEIVER
F 2F 3
SSB
CW/RTTY
P.AMP/ATT
NB
3.5
2
1
1.8
4
14
5
10
24
21
8
7
GENE
50
0
MP-W
TX
XFC
F 4
F 5
FILTER
AM/FM
VOX/BK-IN
MONITOR
CALL
[KEY SPEED]: Max. CCW
MP-R
F-INP
SPLIT
A/B
TWIN PBT
PBTC
MW
V/M
M-CL
LOCK/
SPCH
M-CH
RIT
CLEAR
∂TX
RIT/∂TX
TS
LOCK
3
7
6
18
28
9
144
ENT
RX
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
F 1
F 2F 3
F 4
F 5
F 1
F 2 F 3 F 4 F 5
AGC DUP CMP TBW SCP
AGC DUP CMP TBW SCP
TX
BW=WIDE
Push [F4]
Push [F4] for 1 sec. to select the transmit filter width.
The selected transmit filter width
is displayed for approx. 1 sec.
3. DSP TX Audio Pass Band
TX Bass
SSB
O
1
TX Treble
SSB
O
2
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
Wide : 2.8 kHz ; Great Full Audio
Mid :2.4 kHz ; Great for operators with
deep full voices
Nar : 2.2 kHz ; 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 IC746PRO 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.
[F1 ≤]
QUICK REFERENCE GUIDE
[F2 ≥] [F4 TCN]
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 ≤] or [F2 ≥] to change to the desired
component.
1. TX Bass
This item adjusts the bass level of the transmit audio
tone from –5 dB to +5 dB in 1 dB steps.
2. TX Treble
This item adjusts the treble level of the transmit audio
tone from –5 dB to +5 dB in 1 dB steps.
Verify you have selected a clear frequency
and call out your CQ!
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.
X
1
Recommended level
RF gain
adjustable
range
Maximum
RF gain
S-meter
squelch
Noise squelch (FM mode)
Squelch is
open.
MODE
SSB, CW
RTTY
AM, FM
AUTO
RF GAIN
SQL
SQL
SET MODE SETTING
SQL
SQL
RF GAIN + SQL
RF GAIN + SQL
RF GAIN + SQL
(dot)
(com)
(dash)
POWER
TRANSMIT
PHONES
ELEC-KEY
MIC
NR
A
/NOTCH
TUNER
ANT
HF/VHF TRANSCEIVER
NR
NOTCH
AF
MIC GAIN
RF PWR
CW PITCH
F 1
F 2F 3
F 4
F 5
XFC
MP-W
GENE
50
0
21
7
24
8
28
9
14
5
10
4
18
6
3.5
2
1. 8
1
7
3
144
ENT
MP-R
TX
RX
LOCK
TS
SPLIT
F-INP
A/B
KEY SPEED
P.AMP/ATT
NB
VOX/BK-IN
MONITOR
CALL
LOCK/
SPCH
RF/SQL
i746PRO
MENU
SSB
CW/RTTY
AM/FM
FILTER
q
w
e
r
t
yuio !0 !1
!4!5!6!7 !3 !2
PANEL DESCRIPTION
■ Front panel
q POWER SWITCH [POWER]
➥ 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]
Accepts headphones.
• Output power: 5 mW with an 8 Ω 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.
1
•Selection between the internal electronic keyer, bug-key
and straight key operation can be made in keyer set
mode. (p. 34)
•A straight key jack is separately available on the rear
panel. See [KEY] on p. 7.
•Keyer polarity (dot and dash) can be reversed in keyer
set mode. (p. 34)
•4-channel memory keyer is available for your convenience. (p. 30)
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’clock position is recommended for any setting
of the [RF/SQL] control.
•The control can be set as ‘Auto’ (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)
• When setting as RF gain/squelch control
PANEL DESCRIPTION
NR NOTCH
OFF
Decreases
Increases
NR NOTCH
Low frequency High frequency
Slow Fast
KEY SPEED
CW PITCH
IncreasesDecreases
RF PWR
IncreasesDecreases
AF RF/SQL
No audio output
Max. audio output
Decreases Increases
MIC GAIN
Recommended level for
an Icom microphone
IncreasesDecreases
Squelch is
open.
S-meter
squelch
S-meter squelch
threshold
Noise squelch
threshold
(FM mode)
Shallow Deep
Noise squelch (FM mode)
Minimum RF gain
Adjustable
range
Maximum
RF gain
1
•When functioning as RF gain control
(Squelch is fixed open; SSB, CW, RTTY only)
•When functioning as squelch control
(RF gain is fixed at maximum.)
While rotating the RF gain control, noise may be
heard. This comes from the DSP unit and does not
indicate an equipment malfunction.
u MIC GAIN CONTROL [MIC GAIN]
Adjusts microphone input gain.
•The transmit audio tone in SSB, AM and FM modes can
be adjusted in tone control set mode. (p. 89)
!0 CW PITCH CONTROL [CW PITCH] (p. 28)
Shifts the received CW audio pitch and monitored
CW audio pitch without changing the operating frequency.
•The pitch can be changed from 300 to 900 Hz in approx.
25 Hz steps.
!1 ELECTRONIC CW KEYER SPEED CONTROL
[KEY SPEED] (p. 28)
Adjusts the internal electronic CW keyer’s speed.
• 6 wpm (min.) to 60 wpm (max.) can be set.
!2 AUTO NOTCH/MANUAL NOTCH SWITCH
[A/NOTCH] (p. 53)
Toggles the notch function between manual and automatic when pushed.
•“NOTCH” appears when manual; “A NOTCH” appears
when automatic notch is selected.
!3 NOTCH CONTROL [NOTCH] (outer control; p. 53)
Adjusts the notch filter frequency to remove an in-
terfering signal.
✔
How to set the microphone gain.
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.
i AF CONTROL [AF] (inner control)
Varies the audio output level from the speaker.
o RF POWER CONTROL [RF PWR]
Continuously varies the RF output power from minimum (less than 5 W*) to maximum (100 W*).
* AM mode: less than 5 W to 40 W
!4 ANTENNA SELECTOR SWITCH [ANT] (p. 75)
Switches the antenna connector selection between
ANT1 and ANT2 when pushed.
!5 NOISE REDUCTION LEVEL CONTROL [NR]
(inner control; p. 53)
Adjusts the noise reduction level when the noise reduction is in use. Set for maximum readability.
ANTENNA TUNER SWITCH [TUNER] (pgs. 76, 77)
!6
➥ Turns the antenna tuner ON and OFF (bypass)
when pushed momentarily.
➥ Starts to tune the antenna manually when
pushed for 1 sec.
•When the tuner cannot tune the antenna, the tuning
circuit is bypassed automatically after 20 sec.
!7 NOISE REDUCTION SWITCH [NR] (p. 53)
Switches the noise reduction ON and OFF.
•“NR” appears while the noise reduction is activated.
2
1
AM/FM
CW/RTTY
SSB
NR
A
/NOTCH
TUNER
ANT
HF/VHF TRANSCEIVER
NR
NOTCH
AF
MIC GAIN
RF PWR
CW PITCH
F 1
F 2F 3
F 4
F 5
XFC
MP-W
GENE
50
0
21
7
24
8
28
9
14
5
10
4
18
6
3.5
2
1. 8
1
7
3
144
ENT
MP-R
TX
RX
LOCK
TWIN PBT
M-CH
RIT
CLEAR
∂TX
RIT/∂TX
TS
SPLIT
PBTC
F-INP
A/B
V/M
MW
M-CL
KEY SPEED
P.AMP/ATT
NB
VOX/BK-IN
MONITOR
CALL
LOCK/
SPCH
RF/SQL
i746PRO
MENU
SSB
CW/RTTY
AM/FM
FILTER
#7
#6
#5
#4
#3
#2
#1
#0
!9 @0 @1!8 @2 @3 @4
@6@5 @7 @8 @9
PANEL DESCRIPTION
■ Front panel (continued)
!8 MULTI-FUNCTION SWITCHES [F1]–[F5]
!9 MENU SWITCH [MENU]
@0 MODE SWITCHES
➥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 pro-
gramming or memory name. (pgs. 31, 67)
Push to change the set of functions assigned to the
multi-function switches.
• Toggles between menu 1 (M1) and menu 2 (M2).
Selects the desired mode. (p. 23)
•Announces the selected mode when an optional UT-102
is installed. (p. 90)
➥ 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 re-
verse)
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.
@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
ON and OFF.
✔
What is the preamp?
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.
✔
What is the attenuator?
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
pushed for 1 sec.
3
PANEL DESCRIPTION
Low shift High shift
RIT/∂TX
1
@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 “fast exchanges” 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.
#0 RIT SWITCH [RIT] (p. 48)
➥
Turns the RIT function ON and OFF when pushed.
• Use the [RIT/∂TX] control to vary the RIT frequency.
➥ Adds the RIT shift frequency to the operating fre-
quency 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/∂TX 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∂∂TX SWITCH [∂∂TX] (p. 57)
➥ Turns the ∂TX function ON and OFF when
pushed.
•Use the [RIT/∂TX] control to vary the ∂TX frequency.
➥ Adds the ∂TX shift frequency to the operating
frequency when pushed for 1 sec.
✔
What is the ∂∂TX function?
The ∂TX 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.
@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 read-
out frequency and S-meter indication when an
optional UT-102 is installed. (p. 90)
@9 RIT/∂∂TX CONTROL [RIT/∂∂TX] (pgs. 48, 57)
Shifts the receive and/or transmit frequency without
changing the transmit and/or receive frequency
while the RIT and/or ∂TX 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.
#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
Quick tuning indicator
1
A
/NOTCH
NER
ANT
HF/VHF TRANSCEIVER
NOTCH
MIC GAIN
RF PWR
CW PITCH
F 1
F 2F 3
F 4
F 5
XFC
MP-W
GENE
50
0
21
7
24
8
28
9
14
5
10
4
18
6
3.5
2
1. 8
1
7
3
144
ENT
MP-R
TX
RX
LOCK
TWIN PBT
M-CH
RIT
CLEAR
∂TX
RIT/∂TX
TS
SPLIT
PBTC
F-INP
A/B
V/M
MW
M-CL
KEY SPEED
P.AMP/ATT
NB
VOX/BK-IN
MONITOR
CALL
LOCK/
SPCH
RF/SQL
MENU
SSB
CW/RTTY
AM/FM
FILTER
$7
$4
$5
$6
$3
$2
$1
$0
#9
#8
%2
%0 $9 $8%1
PANEL DESCRIPTION
■ Front panel (continued)
#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 to-
gether 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.
5
$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.
➥ 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-
erating mode of the two VFO’s.
PANEL DESCRIPTION
PBT1
PBT2
TWIN PBT
Low cut High cutCenter
TWIN PBT TWIN PBT TWIN PBT
– +
1
$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.
%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] [1.81] [104]
[GENE • ] [1.8
1
] [289] [145] [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.
$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.
6
!5 !3 t
r
!2 !1 !0 oi uy
qwe
!4
1
(+)
(_)
Rear panel view
PANEL DESCRIPTION
■ Rear panel
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 Ω 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 AUTO-
MATIC 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.
• See p. 8 for connector information.
y
EXTERNAL SPEAKER JACK [EXT SP] (pgs. 15, 101)
Accepts a 4–8 Ω speaker.
u
CI-V REMOTE CONTROL JACK [REMOTE] (p. 95)
➥ Designed for use with a personal computer for re-
mote 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.
• Max. control level: 16 V DC/0.5 A
CAUTION: Be sure the linear amplifiers keying cir-
7
cuit control voltage is compatible to the IC-746PRO,
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.
D DATA SOCKET
PANEL DESCRIPTION
1
DATA
PIN No.
1 DATA IN Input terminal for data transmit. (1200 bps: AFSK/9600 bps: G3RUH, GMSK)
2 GND Common ground for DATA IN, DATA OUT and AF OUT.
3 PTT P PTT terminal for packet operation. Connect ground to transmit data.
12
34
56
Rear panel view
4 DATA OUT Data out terminal for 9600 bps operation only.
5 AF OUT Data out terminal for 1200 bps operation only.
6 P SQL •To avoid unnecessary TNC transmission, connect squelch to the TNC to inhibit trans-
D ACC SOCKETS
ACC (1)
2
4
1
8
6
Rear panel view
PIN No.
1 RTTY Controls RTTY keying “Low” level : Less than 0.6 V
2 GND Connects to ground. Connected in parallel with ACC(2) pin 2.
3
5
3
7
4 MOD
5 AF Fixed, regardless of [AF] position in
NAME DESCRIPTION
Squelch out terminal. Becomes high (+8 V) when the transceiver receives a signal
which opens the squelch.
mission when receiving signals.
• Keep audio output at a normal level, otherwise a “P SQL”signal will not be output.
NAME DESCRIPTION SPECIFICATIONS
“High” level : More than 2.4 V
Output current : Less than 2 mA
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.
HSEND
Input/output pin.
(HF/50 MHz only)
Goes to ground when transmitting.
When grounded, transmits.
Modulator input. Input impedance : 10 kΩ
Connects to a modulator. Input level : Approx. 100 mV rms
AF detector output.
default settings. (see notes below)
Output impedance : 4.7 kΩ
Output level : 100–300 mV rms
ACC (2)
2
4
5
1
Rear panel view
3
6
7
6 SQLS
7 13.8 V 13.8 V output when power is ON.
Squelch output. SQL open : Less than 0.3 V/5 mA
Goes to ground when squelch opens.
SQL closed : More than 6.0 V/100 µA
Output current : Max. 1 A
Connected in parallel with ACC(2) pin 7.
Control voltage : –4 V to 0 V
8 ALC ALC voltage input. Input impedance : More than 10 kΩ
Connected in parallel with ACC(2) pin 5.
PIN No.
NAME DESCRIPTION SPECIFICATIONS
1 8 V Regulated 8 V output.
Output voltage : 8 V ±0.3 V
Output current : Less than 10 mA
2 GND Same as ACC(1) pin 2.
HSEND
3
4 BAND
Band voltage output.
(Varies with amateur band)
Same as ACC(1) pin 3.
Output voltage : 0 to 8.0 V
5 ALC Same as ACC (1) pin 8.
Input/output pin (144 MHz only) Ground level : –0.5 V to +0.8 V
6
VSEND
Goes to ground when transmitting. Output current : Less than 20 mA
When grounded, transmits. Input current (Tx) : Less than 200 mA
7
13.8 V
Same as ACC(1) pin 7.
8
1
q
w
t
!0
o
i
u
y
!1!2!3!4
e
r
PANEL DESCRIPTION
■ LCD display
q FREQUENCY READOUTS
Shows the operating frequency.
w MULTI-FUNCTION METER INDICATION
➥ Shows receiving signal strength, etc. during re-
ceive.
➥ Shows transmit output power, ALC and SWR dur-
ing 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.
!01⁄4 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.
!2 MODE INDICATORS (p. 23)
Shows the selected operating mode.
•“D” appears when SSB data, AM data or FM data mode
is selected.
!3 ANTENNA INDICATOR (p. 75)
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].
9
■ LCD display (continued)
!7
!8
!9
@0
@7
@6
@5
@4
@2
@3
@1
@9
!5
!6
@8
PANEL DESCRIPTION
1
!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.
@4 NOISE REDUCTION INDICATOR (p. 53)
Appears when the noise reduction is activated.
@5 NOTCH INDICATORS (p. 53)
➥ “NOTCH” appears when the manual notch func-
tion is activated.
➥ “ANOTCH” appears when the automatic notch
function is activated.
@6 SPLIT INDICATOR (pgs. 59, 60)
Appears during split operation.
@7 MEMORY INDICATOR (p. 62)
Appears during memory mode.
@8 VFO INDICATORS (p. 20)
Indicates whether VFO A or VFO B is selected.
@9 RIT/∂∂TX INDICATORS (pgs. 48, 57)
Appears during RIT or ∂TX operation and indicates
the frequency offset.
10
1
F 5
VSC
F 4
TCN
F 3
SWR
F 2
MEM
F 1
SCN
F 1
F 2F 3
F 4
F 5
SCN MEM SWR TCN VSC
PANEL DESCRIPTION
■ Multi function switches
DD
M1 FUNCTIONS
During SSB operation
AGC DUP CMP TBW SCP
F 1
F 2F 3
F 4
1
⁄4 TUNING FUNCTION (p. 21)
1/4
F 3
F 5
Push to turn the 1⁄4 tuning function
ON/OFF.
•“ ” indicator appears when the 1⁄
function is ON.
4 tuning
During SSB data operation
AGC DUP 1/4 SCP
F 1
F 2F 3
F 4
During CW operation
AGC DUP 1/4 KEY SCP
F 1
F 2F 3
F 4
During RTTY operation
AGC DUP 1/4 RTY SCP
F 1
F 2F 3
F 4
During AM operation
AGC DUP CMP SCP
F 1
F 2F 3
F 4
During FM operation
AGC DUP CMP TON SCP
F 1
F 2F 3
F 4
TRANSMISSION BANDWIDTH (p. 58)
TBW
F 5
F 4
Push to select the transmission bandwidth.
•Bandwidth is selectable from narrow, middle
and wide.
MEMORY KEYER MENU (p. 29)
KEY
F 4
F 5
Push to select the memory keyer or keyer
send menu, depending on the KEYER
1st Menu setting in the set mode (p. 86).
RTTY MENU (p. 36)
RTY
F 4
F 5
Push to select the RTTY menu.
BAND SCOPE FUNCTION (p. 47)
SCP
F 5
F 5
DD
M2 FUNCTIONS
F 5
Push to select the band scope screen.
AGC (p. 49)
AGC
➥ Push momentarily to change the time
F 1
constant of the AGC circuit.
➥ Push for 1 sec. to enter to the AGC set
mode.
DUPLEX (p. 44)
DUP
➥ Push momentarily to select the duplex di-
F 2
rection or turn the function OFF.
•“DUP–” or “DUP+” indicator appears during
duplex operation.
➥ Push for 1 sec. to turn the one-touch re-
peater function ON/OFF.
SPEECH COMPRESSOR (p. 58)
CMP
➥ Push momentarily to turn the speech
F 3
compressor function ON/OFF.
•“COMP” indicator appears when the speech
compressor is ON.
➥ Push for 1 sec. to enter to the compres-
sor set mode.
SCAN MENU (p. 70)
Push to select the scan menu.
MEMORY NAME MENU (p. 67)
Push to select the memory name screen.
SWR GRAPH FUNCTION (p. 61)
Push to indicate the SWR graph screen.
TONE CONTROL SET MODE (p. 89)
Push to enter the audio tone set mode.
VSC FUNCTION (p. 54)
Push to turn the VSC (Voice Squelch Control) function ON and OFF.
11
■ Microphone (HM-36)
y GND (PTT ground)
t PTT
r Main readout squelch switch
q Microphone input
w +8 V DC output
e Frequency up/down
u GND
(Microphone ground)
i Main readout AF output
(varies with [AF]/[BAL])
q
w
PANEL DESCRIPTION
1
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)
•MICROPHONE CONNECTOR
(Front panel view)
w PTT SWITCH
Push and hold to transmit; release to receive.
[MIC]
Pin No.
w +8 V DC output Max. 10 mA
e
r
FUNCTION DESCRIPTION
Frequency up Ground
Frequency down Ground through 470 Ω
Squelch open “Low” level
Squelch closed “High” level
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.
• HM-36 SCHEMATIC DIAGRAM
MIC
ELEMENT
PTT
MICROPHONE
10µ
RECEIVE
TRANSMIT
+
2k
4700p
0.33µ
4700p
DOWN UP
470
MICROPHONE CABLE MICROPHONE PLUG
+
q
i
w
ert
u
y
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 Ω 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
Coupling ring
w
e
30 mm
10 mm (soft solder)
10 mm
Soft
solder
1–2 mm
solder solder
Slide the coupling ring
down. Strip the cable
jacket and soft solder.
Strip the cable as
shown at left. Soft solder the center conductor.
Slide the connector
body on and solder it.
■ 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.
R WARNING: NEVER connect the [GND]
terminal to a gas or electric pipe, since the connection could cause an explosion or electric shock.
r
30 mm ≈9⁄8
in 10 mm ≈
Screw the coupling
ring onto the
connector body.
3
⁄8
in 1–2 mm ≈
1
⁄16
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.
in
13
■ Required connections
i746PRO
POWER
F 1
MENU SSB
F 2
CW/RTTY
F 3
AM/FM
F 4
FILTER
F 5
XFC
MP-W
GENE
50
MP-R
0
21724828
9
10
4145186
1.8
1
3.5
2
7
3
144
ENT
TS
A/B
SPLIT
F-INP
V/M
M-CL
PBTC
MW
TWIN PBT
M-CH
LOCK/
SPCH
∂TXRIT
CLEAR
RIT/∂TX
CALL
MONITOR
VOX/BK-IN
NB
P.AMP/ATT
KEY SPEED
CW PITCH
RF PWR
MIC GAIN
HF/VHF TRANSCEIVER
TRANSMIT
PHONES
ELEC-KEY
MIC
TUNER
ANT
NR
NOTCH
AF
RF/SQL
NR
A/NOTCH
CW KEY
MICROPHONES (p. 101)
A straight key can be used
when the internal electronic
keyer is turned OFF in keyer
set mode. (p. 34)
HM-36 SM-20
(optional)
(dot)
(com)
(dash)
GROUND (p. 13)
Use the heaviest gauge wire or
strap available and make the
connection as short as possible.
Grounding prevents electrical
shocks, TVI and other problems.
ANTENNA 1, 2 (pgs. 13, 75)
[Example]: ANT1 for 1.8–18 MHz bands
ANT2 for 21–50 MHz bands
DC POWER SUPPLY
STRAIGHT KEY
PS-125
(Optional)
144 MHz ANTENNA (pgs. 13, 75)
Connect a VHF
(60–144 MHz)
antenna;
impedance: 50 Ω.
(+)
(_)
• Front panel
INSTALLATION AND CONNECTIONS
2
• Rear panel
14
2
POWER
TRANSMIT
PHONES
ELEC-KEY
MIC
NR
A
/NOTCH
TUNER
ANT
HF/VHF TRANSCEIVER
NR
NOTCH
AF
MIC GAIN
RF PWR
CW PITCH
F 1
F 2F 3F 4F 5
XFC
MP-W
GENE
50
0
21
7
24
8
28
9
14
5
10
4
18
6
3.5
2
1.8
1
7
3
144
ENT
MP-R
TX
RX
LOCK
TWIN PBT
M-CH
RIT
CLEAR
∂TX
RIT/∂TX
TS
SPLIT
PBTC
F-INP
A/B
V/M
MW
M-CL
KEY SPEED
P.AMP/ATT
NB
VOX/BK-IN
MONITOR
CALL
LOCK/
SPCH
RF/SQL
i746PRO
MENU
SSB
CW/RTTY
AM/FM
FILTER
HEADPHONES
MIC
The AFSK modulation signal
can be input from [MIC]. (p. 78)
AH-2b
AH-4 (p. 77)
ANTENNA 1, 2 (p. 17)
Connects a linear amplifier,
antenna selector, etc.
[SEND], [ALC] (p. 17)
Used for connecting a
non-Icom linear amplifier.
When using the AH-4, it must
be connected to the [ANT1]
connector.
[REMOTE] (p. 95)
Used for computer control and transceive operation.
[D ATA] (p. 78)
EXTERNAL SPEAKER (p. 101)
SP-21
(optional)
ACC SOCKETS (pgs. 8, 78)
INSTALLATION AND CONNECTIONS
■ Advanced connections
• Front panel
• Rear panel
15
INSTALLATION AND CONNECTIONS
30 A fuses
AC cable
Transceiver
AC outlet
A DC power supply
13.8 V; at least 23 A
Black_Red
+
to DC power
socket
Supplied
DC power cable
12 V
battery
Supplied
DC power cable
+ red
_ black
Crimp
Solder
Grommet
PS-125
Connect to an AC outlet
using the supplied AC cable.
DC power cable
DC power
socket
Transceiver
2
■ 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
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.
Red : positive + terminal
Black : negative _ terminal
CONNECTING A DC POWER SUPPLY
CONNECTING A VEHICLE BATTERY
NEVER connect to
a 24 V battery.
NOTE: Use terminals for
the cable connections.
NEVER connect to a battery without supplied DC
fuses, otherwise a fire hazard may occur.
16
2
To an
antenna
ACC(1)
ANT
ANT1
ACC(2)
INPUT1
REMOTE
EXCITER
1
1&2
GND
GND
IC-PW1
AC outlet
(Non-European versions: 100—120/220—240 V
European version : 230 V)
Ground
Transceiver
REMOTE
Remote control cable (supplied with the IC-PW1)
ACC cable (supplied with the IC-PW1)
Be sure to connect the cable
to the 7-pin ACC(2) jack.
Coaxial cable
(supplied with the IC-PW1)
Coaxial cable (from AH-4)
ANT1
Transceiver
Ground
AH-4
Control cable
Long wire or optional AH-2b
50 Ω coaxial cable
Non-Icom linear amplifier
SEND
ALC
To an
antenna
RF OUTPUT RF INPUT
ALC
SEND
ANT1
Transceiver
INSTALLATION AND CONNECTIONS
■ Linear amplifier connections
CONNECTING THE IC-PW1
Use the [ANT1] connector when connecting a linear
amplifier.
Turn OFF the transceiver’s antenna tuner while tuning the IC-PW1’s tuner.
CONNECTING A NON-ICOM LINEAR AMPLIFIER
■ External antenna tuner connections
CONNECTING THE AH-4
The AH-4 must be connected to [ANT1].
17
R WARNING:
Set the transceiver output power and linear amplifier ALC output level referring to the linear amplifier
instruction manual. Be sure the linear amplifier keying circuit control voltage is compatible with the IC746PRO, before connecting to [SEND] jack.
The ALC input level must be in the range 0 V to –4
V, and the transceiver does not accept positive voltage. Non-matched ALC and RF power settings
could cause a fire or ruin the linear amplifier.
The specifications for the SEND relay are 16 V/DC
0.5 A. If this level is exceeded, a large external
relay must be used.
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