Icom M700 Mods -

The single most famous modification for the IC-M700 is the frequency expansion mod, often called the "MARS/CAP mod" (Military Affiliate Radio System / Civil Air Patrol).

The Problem: As a marine radio, the stock M700 is locked to the ITU maritime bands. It transmits only on frequencies between 1.6 MHz and 27.5 MHz in specific marine channels (with some gaps). It will not transmit on the 80m, 40m, 20m, or 17m amateur bands out of the box. You can listen to hams, but you cannot talk back.

The Solution: The frequency restriction is controlled by a set of diode matrices on the main logic board (PLL Unit). By adding or removing specific diodes, you can unlock full continuous TX coverage from 1.6 MHz to 29.999 MHz. icom m700 mods

The M700 was designed for intelligibility on a pitching ship, not for musical SSB audio. The stock audio path rolls off highs above 2 kHz, making voices sound "boaty" and muffled.

If you have a steady hand and an oscilloscope, consider these: The single most famous modification for the IC-M700

Warning: This involves soldering on delicate surface-mount pads. If you are uncomfortable, find an experienced tech.

Result: Fire up the radio, hold the mode switch to "CW," and turn the VFO knob. You should now hear the relay click across the entire HF spectrum. Press PTT – you will have transmit capability on every HF ham band. Result: Fire up the radio, hold the mode

Note: This mod also increases power slightly on some bands – ensure you have a good dummy load and SWR meter.