INSTRUCTION MANUAL VHF/HF ALL MODE TRANSCEIVER i746 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. 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-746. PRECAUTIONS RWARNING! HIGH VOLTAGE! NEVER attach an antenna or internal antenna connector during transmission. This may result in an electric shock or burn. AVOID placing the transceiver against walls or putting anything on top of the transceiver. This will obstruct heat dissipation. During mobile operation, DO NOT operate the transceiver without running the vehicle's engine. When transceiver 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-746 may damage the transceiver. RNEVER apply AC to the [DC13.8V] socket on the transceiver rear panel. This could cause a fire or ruin the transceiver. RNEVER apply more than 16 V DC, such as a 24 V battery, to the [DC13.8V] socket on the transceiver rear panel. This could cause a fire or ruin the transceiver. RNEVER 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 allow children to play with equipment containing a radio transmitter. 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. EXPLICIT DEFINITIONS The explicit definitions described below apply to this instruction manual. DEFINITION Personal injury, fire hazard or electric RWARNING shock may occur. CAUTION NOTE Equipment damage may occur. If disregarded, inconvenience only. No risk of personal injury, fire or electric shock. The IC-746's which display the "CE" symbol, comply with the essential requirements of the 89/336/EEC directive for Electromagnetic Compatibility. This compliance is based on conformity with the ETSI specification prETS300 684 (EMC product standard for Commercially Available Amateur Radio Equipment). BUILT-IN DSP DSP WORD The IC-746's DSP digitally transposes receive audio components in all modes of operation to produce desired AF frequency characteristics at the IF stage of the transceiver. DSP provides the following functions: Noise reduction--reduces various types of noise and enhances receive signal components only. Automatic notch filter--automatically reduces single beat interference and protects the receive voice signals. Selectable APF--a total of 3 passband widths are selectable (80/160/320 Hz), for super-narrow filter APF functions in CW mode. The APF center frequency is adjustable. ii TABLE OF CONTENTS IMPORTANT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . EXPLICIT DEFINITIONS . . . . . . . . . . . . . . . . . . . . . BUILT-IN DSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TABLE OF CONTENTS . . . . . . . . . . . . . . . . . . . . . ii ii ii ii iii 7-3 Transferring a memory to VFO . . . . . . . . . . . 7-4 Clearing a memory . . . . . . . . . . . . . . . . . . . . 7-5 Selecting the call channel . . . . . . . . . . . . . . 7-6 Programming a memory . . . . . . . . . . . . . . . . 7-7 Programming the call channel . . . . . . . . . . . 7-8 Programming scan edges . . . . . . . . . . . . . . 7-9 Assigning memory names . . . . . . . . . . . . . . 7-10 Memo pads . . . . . . . . . . . . . . . . . . . . . . . . 50 50 51 51 52 52 53 54 1 PANEL DESCRIPTION . . . . . . . . . . . . . . . . . . 2­7 1-1 Front panel . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1-2 Rear panel . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1-3 Function display . . . . . . . . . . . . . . . . . . . . . . . 7 2 MENU SELECTION . . . . . . . . . . . . . . . . . . . . . 8­9 2-1 Menu set 1 flow chart . . . . . . . . . . . . . . . . . . . 8 2-2 Menu set 2 flow chart . . . . . . . . . . . . . . . . . . . 9 3 BASIC OPERATION . . . . . . . . . . . . . . . . . . 10­17 3-1 Before operating . . . . . . . . . . . . . . . . . . . . . . 10 3-2 Squelch and receive (RF) sensitivity . . . . . . 12 3-3 Selecting VFO/memory mode . . . . . . . . . . . 13 3-4 Toggling between VFO A/B and transferring contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3-5 Setting a band and frequency . . . . . . . . . . . 14 3-6 Selecting an operating mode . . . . . . . . . . . . 17 4 USING DIFFERENT OPERATING MODES . 18­36 4-1 Operating SSB . . . . . . . . . . . . . . . . . . . . . . . 18 4-2 Operating CW . . . . . . . . . . . . . . . . . . . . . . . . 20 4-3 Operating RTTY (FSK) . . . . . . . . . . . . . . . . . 28 4-4 Operating AM . . . . . . . . . . . . . . . . . . . . . . . . 30 4-5 Operating FM . . . . . . . . . . . . . . . . . . . . . . . . 32 4-6 Repeater operation . . . . . . . . . . . . . . . . . . . 34 4-7 Packet operation . . . . . . . . . . . . . . . . . . . . . . 36 5 FUNCTIONS FOR RECEIVE . . . . . . . . . . . . 37­42 5-1 Simple band scope . . . . . . . . . . . . . . . . . . . . 37 5-2 Preamp and attenuator . . . . . . . . . . . . . . . . 38 5-3 RIT function . . . . . . . . . . . . . . . . . . . . . . . . . 38 5-4 AGC function . . . . . . . . . . . . . . . . . . . . . . . . 39 5-5 1/4 function . . . . . . . . . . . . . . . . . . . . . . . . . . 39 5-6 NB function . . . . . . . . . . . . . . . . . . . . . . . . . . 39 5-7 Noise reduction . . . . . . . . . . . . . . . . . . . . . . 40 5-8 Auto notch (ANF) function . . . . . . . . . . . . . . 40 5-9 Dial lock function . . . . . . . . . . . . . . . . . . . . . 40 5-10 Twin PBT . . . . . . . . . . . . . . . . . . . . . . . . . . 41 5-11 Selecting IF filters . . . . . . . . . . . . . . . . . . . . 42 6 FUNCTIONS FOR TRANSMIT . . . . . . . . . . . 43­48 6-1 VOX function . . . . . . . . . . . . . . . . . . . . . . . . . 43 6-2 Break-in function . . . . . . . . . . . . . . . . . . . . . 44 6-3 :TX function . . . . . . . . . . . . . . . . . . . . . . . . 45 6-4 Monitor function . . . . . . . . . . . . . . . . . . . . . . 45 6-5 Speech compressor . . . . . . . . . . . . . . . . . . . 46 6-6 Split frequency operation . . . . . . . . . . . . . . . 47 6-7 Quick split function . . . . . . . . . . . . . . . . . . . . 48 7 MEMORY CHANNELS . . . . . . . . . . . . . . . . 49­54 7-1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 7-2 Memory channel selection . . . . . . . . . . . . . . 49 8 SCAN OPERATION . . . . . . . . . . . . . . . . . . . 55­58 8-1 Scan types . . . . . . . . . . . . . . . . . . . . . . . . . . 55 8-2 Programmed scan and fine programmed scan . . . . . . . . . . . . . . . . . 56 8-3 Memory scan . . . . . . . . . . . . . . . . . . . . . . . . 57 8-4 Select memory scan . . . . . . . . . . . . . . . . . . . 57 8-5 :F scan and fine :F scan . . . . . . . . . . . . . . 58 9 INTERNAL ANTENNA TUNER . . . . . . . . . . . . . 59 9-1 Before operating . . . . . . . . . . . . . . . . . . . . . . 59 9-2 Tuner operation . . . . . . . . . . . . . . . . . . . . . . . 59 10 SET MODE . . . . . . . . . . . . . . . . . . . . . . . . . 60­64 10-1 Selecting set mode . . . . . . . . . . . . . . . . . . . 60 10-2 Set mode items . . . . . . . . . . . . . . . . . . . . . 60 11 ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . 65­66 11-1 Tuning dial brake . . . . . . . . . . . . . . . . . . . . 65 11-2 Frequency calibration . . . . . . . . . . . . . . . . . 65 11-3 Measuring SWR . . . . . . . . . . . . . . . . . . . . . 66 11-4 Adjusting the LCD . . . . . . . . . . . . . . . . . . . 66 12 SETUP AND CONNECTIONS . . . . . . . . . . 67­75 12-1 Front panel . . . . . . . . . . . . . . . . . . . . . . . . . 67 12-2 Rear panel . . . . . . . . . . . . . . . . . . . . . . . . . 68 12-3 Selecting a location . . . . . . . . . . . . . . . . . . 69 12-4 Power supply connections . . . . . . . . . . . . . 69 12-5 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . 70 12-6 Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 12-7 Data communications . . . . . . . . . . . . . . . . . 72 12-8 RTTY connections . . . . . . . . . . . . . . . . . . . 73 12-9 Remote jack . . . . . . . . . . . . . . . . . . . . . . . . 74 13 OPTIONAL INSTALLATIONS . . . . . . . . . . 76­80 13-1 Opening the transceiver's case . . . . . . . . . 76 13-2 UT-102 VOICE SYNTHESIZER UNIT . . . . . . . . . 77 13-3 CR-282 HIGH STABILITY CRYSTAL UNIT . . . . . 77 13-4 Optional IF filters . . . . . . . . . . . . . . . . . . . . 78 13-5 Linear amplifier connections . . . . . . . . . . . 79 13-6 External antenna tuner connections . . . . . . 80 14 MAINTENANCE . . . . . . . . . . . . . . . . . . . . . 81­83 14-1 Fuse replacement . . . . . . . . . . . . . . . . . . . 81 14-2 Resetting the CPU . . . . . . . . . . . . . . . . . . . 81 14-3 Troubleshooting . . . . . . . . . . . . . . . . . . . . . 82 15 SPECIFICATIONS AND OPTIONS . . . . . . 84­85 15-1 Specifications . . . . . . . . . . . . . . . . . . . . . . . 84 15-2 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 iii 1 Å PANEL DESCRIPTION 1-1 Front panel 6 7 8 9 PHONES Å TUNER ANT APF 1 2 POWER NR TRANSMIT 3 ELEC-KEY NR AF APF/ANF RF/SQL !0 !1 !2 !3 i 4 MIC 5 q POWER SWITCH [POWER] Push momentarily to turn power ON. (p. 11) · Turn the optional DC power supply ON in advance. · When the tuner cannot tune the antenna, the tuning circuit is bypassed automatically after 20 sec. Push and hold to turn power OFF. w TRANSMIT SWITCH [TRANSMIT] Toggles between transmit and receive. · The [TX] indicator lights red while transmitting and the [RX] indicator lights green when the squelch is open. u ANTENNA SELECTOR SWITCH [ANT] (p. 71) Toggles between the HF and 50 MHz antenna connectors. i NOISE REDUCTION LEVEL CONTROL [NR] (p. 40) Adjusts the noise reduction level when the noise reduction function is in use. Set for maximum readability. o AUDIO PEAK FILTER CONTROL [APF] (p. 20) Varies the peak frequency of the audio peak filter to pick out a CW signal from interference while the APF function is ON. !0 NOISE REDUCTION SWITCH [NR] (p. 40) Toggles the noise reduction function ON and OFF. Functions in SSB, CW and RTTY modes. !1 AUDIO PEAK FILTER/AUTO NOTCH SWITCH [APF/ANF] Toggles between the audio peak (p.20) and auto notch (p. 40) functions. · The audio peak filter functions in CW mode only; the auto notch functions in SSB, FM and AM modes only. · The APF or ANF indicator appear in the display depending on which function is selected. e HEADPHONE JACK [PHONES] (p. 67) Accepts headphones. · When headphones are connected, the internal speaker or connected external speaker does not function. r ELECTRONIC KEYER JACK [ELEC-KEY] (p. 67) 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 mode. · A straight key jack is separately available on the rear panel. · Key polarity (dot and dash) can be reversed in keyer set mode. · 4-channel memory keyer is available for your convenience. t MICROPHONE CONNECTOR [MIC] Accepts the supplied or optional microphone. · See p. 85 for appropriate microphones. · See p. 67 for microphone connector information. When the APF indicator appears, push this switch for 1 sec., one or more times to select 320 Hz, 160 Hz or 80 Hz bandwidths. · Use the [APF] control to vary the peak frequency. y ANTENNA TUNER SWITCH [TUNER] (p. 59) Turns the antenna tuner ON and OFF (bypass) when pushed momentarily. Starts to tune the antenna manually when pushed for 2 sec. 2 !2 AF CONTROL [AF] (inner control; p. ...