User manual ICOM IC-281H

[. . . ] NEVER connect the transceiver to an AC outlet directly. This may pose a fire hazard or result in an electric shock. In maritime mobile operation, KEEP the transceiver and microphone as far away as possible (at least 1 m) from the magnetic navigation compass to prevent erroneous indications. USE an Icom microphone and/or handset only (supplied or optional). [. . . ] In such cases, the transmit frequency should be monitored before transmitting to prevent interference to other stations. Push and hold [TX FREQ] to monitor the transmit frequency. TX FREQ · The display shows the transmit frequency. 8 RECEIVE AND TRANSMIT 4 I Functions for receive D Squelch function The squelch function detects signals with voice components and squelches (mutes) unwanted signals such as unmodulated beat signals. When you need to receive weak signals, the squelch should be turned off. Push [SQL] to toggle the function on and off. DUP SQL · "SQL" appears when the squelch function is turned on. D Noise blanker The noise blanker function reduces pulse type noise such as that coming from engine ignitions. The noise blanker may distort reception of strong signals. In such cases, the noise blanker should be turned off. Push [NB] to toggle the function on and off. RX DUP NB · "NB" appears when the noise blanker function is turned on. D AGC off function The receiver gain is automatically adjusted according to received signal strength with the AGC (Automatic Gain Control) function to prevent distortion from strong signals and to obtain a constant output level. When receiving weak signals with adjacent strong signals or noise, the AGC function may reduce the sensitivity. In this situation, the AGC function should be deactivated. Push [AGC] to toggle the function on and off. RX DUP AGC · "ê" appears when the AGC function is deactivated. D Clarity control Voice signals received from other stations may be difficult to receive. This may sometimes happen if a station is transmitting slightly off frequency. Full break-in allows you to receive signals between transmitted keying pulses during CW transmission. Semi break-in allows you to mute receiving until keying stops with some delay time. Full break-in Automatic keying without delay time (default) Semi break-in Automatic keying with delay time OFF Manual transmission necessary for keying 12 SET MODE 5 (9) LCD contrast The LCD contrast can be adjusted through 10 levels to suit transceiver mounting angle, location and ambient lighting. Lowest contrast (default: 7) Highest contrast (10) ID number setting for remote control When connecting an external controller such as a personal computer, 2-digit ID codes are required to access the transceiver. The IC-281H adopts NMEA0183 format and uses a "proprietary sentence" for remote control. NMEA ID: 1 (default: 2) NMEA ID: 99 (11) Remote control input terminal Remote control signals can be input via the [REMOTE] socket or [CLONE] jack. [REMOTE] socket (default) [CLONE] jack (12) Display backlighting Allows you to select 1 of 4 intensity levels for the display backlighting. Dimmest (default) Brightest (13) Group A channel inhibit This item allow you to set the number of usable channels in channel group A, up to a maximum of 50 channels. Minimum number of channels set for Group A: 1 Maximum number of channels set for Group A: 50 (default) 13 5 SET MODE (14) Group B channel inhibit This item allow you to set the number of usable channels in channel group B, up to a maximum of 50 channels. Minimum number of channels set for Group B: 1 Maximum number of channels set for Group B: 50 (default) (15) Group C channel inhibit This item allow you to set the number of usable channels in channel group C, up to a maximum of 50 channels. Minimum number of channels set for Group C: 1 Maximum number of channels set for Group C: 50 (default) 14 CONNECTIONS AND INSTALLATION I Connections on rear panel e o 6 q u w r t y i External speaker Optional AT-130 12 V battery q ANTENNA CONNECTOR (p. 19) Connects a 50 HF band antenna with a 50 matched coaxial cable and a PL-259 plug. Connects a ship's (or vehicle's) ground. 17) REMOTE socket for Marine and General versions. y EXTERNAL SPEAKER JACK Connects a 4­16 external speaker using a 1/4" monaural plug. This external audio is not muted by the [SPEAKER] switch on the front panel. u TUNER RECEPTACLE Connects a control cable to an optional AT-130 ANTENNA TUNER. A female connector is supplied for connection. i DC POWER RECEPTACLE Connects to a regulated 12­16 V DC power source such as a 12 V battery or DC power supply using the supplied DC power cable. R CAUTION: DO NOT connect to a 24 V battery. This will damage the transceiver. o FUSE HOLDERS Hold two 30 A fuses for +ve and ­ve terminals. [. . . ] · Antenna is not properly matched to the operating frequency. RECEIVE · Push [TUNE] to tune the connected antenna tuner or select "automatic tuning" using set mode when an optional AT-130 is connected. · Wrong tuner condition is selected in set · Set the proper condition for the connected tuner. · Push [MODE] to select the proper operating mode. · Push [AGC] to activate the AGC function. [. . . ]