The Icom M502 fits well in the upper echelon of the Icom marine VHF radio lineup with its large front panel, top performance, and fairly extensive feature list.
This fixed mount VHF will couple to a remote microphone and is capable of interfacing with an optional voice scrambler.
Microphone control capability is limited to changing radio channels and quick selecting 16 or 9. When it is connected to a GPS this Icom VHF will display position and time.
The M502 achieved excellent overall performance ratings. The transmitter demonstrated very stable power output throughout the entire gamut of tests while transmitter frequency stability was rated good.
The receiver tested well too, with a sensitivity rating of excellent and a selectivity specification of greater than 75 dB. Audio output was rated excellent with measured sound pressure level measured at 93 dBA.
We rated the display on the Icom M502 good. It is quite functional with 7 levels of backlighting adjustment, the ability to display Alpha channels when selected, and the display of both transmit and receive icons; the screens are only about half the size of the largest in the group.
This radio has one-button capability for the following functions: selecting International, US, or Canadian channels, shifting to weather channels, changing transmitter power output, running a tag scan, and selecting receiver attenuation.
This last one lets you set the radio receiver for either distant or local reception. In a congested harbor with lots of VHF radio traffic a receiver can be overwhelmed with signals, by setting the unit to local the radio will cut out most of the weak signals and provide better reception of the stronger nearby signals.
Small rotary knobs located on the lower left side of the radio face control volume and squelch. A large knob in the center of the face is used for channel selection.
This marine VHF can listen for signals on channel 16 while monitoring other channels via Dualwatch and Tri-watch. Scanning several channels at once is accomplished via normal or priority scanning.
Normal looks at each channel in numerical order while priority checks channel 16 between other channels. Another refinement in scanning found in Icom radios is channel tagging. Channels are tagged to be includes in a scan and not tagged to be omitted.
Digital Selective Calling
The Icom M502 has extensive DSC capabilities. They include the capacity to make distress, individual, all ships, group, position request, position send, and geographical calls.
Odds and Ends
The main thing we found missing in this radio was the lack of any hailer or automatic fog signal capability.
This Icom VHF radio performed very well, though it lacked all the features one would find on the most expensive marine VHFs. This radio carries a 3-year warranty.