User manual ICOM IC-746

[. . . ] 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!NEVER attach an antenna or internal antenna connector during transmission. [. . . ] 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. These can both be set independently for each band. Push [P. AMP/ATT] momentarily one or more times [P. AMP/ATT] inside dotted line is 1. 6­60 MHz operation to set the preamp OFF, set preamp 1 ON or set preamp2 ON. · When the preamp is ON, either preamp 1 or preamp2 appears in the function display. · When operating on the 144 MHz band, the preamp can only be set to ON or OFF--there is no preamp1 and preamp2. · Preamp1 activates the 10 dB preamp for the 1. 8 to 54 MHz range; preamp2 activates the 16 dB high-gain preamp for the 21 to 60 MHz range; preamp activates the VHF preamp for the 144 to 146 MHz range (108 to 174 for the USA version). P. AMP/ATT P. AMP/ATT Push [P. AMP/ATT] for 2 sec. once or twice to set the P. AMP/ATT attenuator ON or OFF. P. AMP/ATT · "ATT" appears in the display when the function is set ON. P. AMP/ATT P. AMP/ATT P. AMP/ATT 5-3 RIT function RIT (receiver incremental tuning) shifts the receive frequency up to ±9. 99 kHz in 10 Hz steps without shifting the transmit frequency. This is useful for fine tuning stations which call you on an off-frequency or when you prefer to listen to slightly different sounding voice characteristics, etc. Push [RIT] to turn the RIT function ON and OFF. · RIT and the RIT frequency appear in the function display when the function is ON. [RIT/TX] [RIT] [CLEAR] Rotate [RIT/:TX] to set a receive frequency shift. · Push [CLEAR] for 2 sec. to add the shift frequency to the operating frequency. 1 ANT USB S Po ALC SWR 1 3 20 5 7 9 50 20 40 60 100% RIT VFOA BLANK 1 1. 5 2 3 CH RIT indications s RIT MONITOR FUNCTION 38 When the RIT function is ON, pushing and holding [XFC] allows you to monitor the operating frequency directly (RIT is temporarily cancelled). FUNCTIONS FOR RECEIVE 5 5-4 AGC function 1 ANT USB The AGC (auto gain control) controls receiver gain to produce a constant audio output level even when the received signal strength is varied by fading, etc. While menu set 1 is displayed, push [F1](AGC) one or more times to select AGC fast or AGC slow. · The corresponding indicator appears in the display. · AGC slow cannot be selected in FM mode. BLANK S Po ALC SWR 1 3 20 5 7 9 50 20 40 60 100% VFOA CH Push [F1](AGC) for 2 sec. to turn the AGC function OFF. · AGC should normally be set to AGC fast for CW and RTTY operation and to AGC slow for SSB and AM operation. · Turn AGC OFF when receiving a very weak signal near a strong signal. 1 1. 5 2 3 P. AMP 1 AGC OFF FS M1 AGC DUP CMP TCN SCP F1 F2 F3 F4 F5 NOTE: When the AGC function is turned OFF, the S-meter does not function. Toggles AGC ON/OFF AGC indicators 5-5 1/4 function 1 ANT CW 1 4 When the 1/4 function is ON, one complete rotation of the tuning dial changes the frequency by 1. 25 kHz (normally one rotation changes the frequency by 5 kHz). This is convenient when critical setting is required and is only available in CW and RTTY modes. S Po ALC SWR 1 3 20 5 7 9 50 20 40 60 100% Push [CW/RTTY] to select CW or RTTY mode. While menu set 1 is selected, push [F3](1/4) to BLANK VFOA CH toggle the 1/4 function ON and OFF. · When the function is ON, "1/4" appears in the function display. · When the TS function is turned ON, the TS function has priority. 1 1. 5 2 3 P. AMP 1 AGC F M1 AGC DUP 1/4 KEY SCP F1 F2 F3 F4 F5 1/4 function ON/OFF 1/4 function indicator 5-6 NB function The noise blanker reduces pulse-type noise such as that generated by automobile ignition systems. Push [NB] to toggle the noise blanker function ON and OFF. · When the noise blanker function is turned ON in AM mode and a strong signal is received, audio may distort. In this case turn the function OFF. [NB] 39 5 FUNCTIONS FOR RECEIVE 5-7 Noise reduction [NR] DSP The noise reduction function reduces noise components and picks out desired signals which are buried in noise. The received AF signals are converted to digital signals and then the desired signals are separated from the noise. Push [NR] to toggle noise reduction ON and OFF. · "NR" appears when noise reduction is ON. Rotate the [NR] control to obtain the desired level of noise reduction. · Clockwise rotation increases the level of noise reduction; counterclockwise rotation decreases the level of noise reduction. [NR] 5-8 Auto notch (ANF) function DSP The auto notch function automatically attenuates more than 3 beat tones, tuning signals, etc. , even if they are moving. This function is only available in SSB, AM and FM modes. Push a mode key to select SSB, AM or FM mode. Push [APF/ANF] to toggle the auto notch filter ON and OFF. · "ANF" appears when the function is ON. [APF/ANF] 5-9 Dial lock function Lights when the dial lock function is ON The dial lock function prevents accidental frequency changes caused by inadvertently rotating the tuning dial. [. . . ] The internal CPU has malfunctioned. Set [COMP GAIN] to a suitable posi- p. Reset the CPU. (While pushing [F-INP] and [M-CL] push [POWER] to turn power ON. DISPLAY Displayed frequency does not change properly. p. Programmed scan does not start. Squelch is open. Set squelch to the threshold position. p. 12 SCAN The same frequencies have been programmed in scan edge memory channels P1 and P2. [. . . ]