Icom M700 Mods -

The Icom M-700 series (specifically the M-700Pro and its descendants like the M-710) occupies a legendary status in the world of maritime communication. It is the "Toyota Land Cruiser" of marine HF/SSB radios: over-engineered, built like a tank, and capable of far more than its stock configuration suggests.

While modern maritime gear is often "black box" architecture—sealed, software-locked, and disposable—the M-700 is a relic of the golden age of radio. It uses discrete components, robust filters, and an architecture that invites modification.

Here is a deep dive into the culture, technical reality, and specific modifications surrounding the Icom M-700. icom m700 mods

Improve Receiver Sensitivity

  • Mod: Realign the front-end bandpass filters for 20m and 40m (not the marine band). Adjust T1–T5 on the RF unit for max noise on a quiet frequency.

Summary Table of Popular Mods

| Mod | Difficulty | Tools Needed | Benefit | |------|------------|--------------|---------| | MARS/CAP (full TX) | Medium | Soldering iron, diode cutter | Ham band transmit | | TX audio mod | Easy | Soldering iron, capacitor | Clearer voice | | CW filter add-on | Hard | Oscilloscope, filter, PCB | Weak signal CW | | Fan control | Easy | Resistor/thermal switch | Quiet operation | | PLL recap | Medium | Desoldering pump, caps | Reliable lock |

The Icom IC-M700: From Marine Workhorse to Amateur Radio Legend – The Definitive Guide to Mods

In the world of HF radio, few transceivers have achieved the cult status of the Icom IC-M700. Designed as a rugged, commercial-grade marine SSB radiotelephone, it was never intended for the amateur radio market. Yet, decades after its production run, it remains one of the most sought-after platforms for budget-conscious hams, maritime mobile enthusiasts, and off-grid communicators. The Icom M-700 series (specifically the M-700Pro and

Why? Because beneath its utilitarian grey faceplate lies a 150-watt, bulletproof HF transceiver with a receiver that rivals modern mid-tier rigs. However, the M700 has a secret: it is artificially restricted. To turn this marine radio into a true amateur powerhouse, you need to perform a series of well-documented, time-tested modifications.

This guide covers everything from unlocking the frequency bands to improving audio clarity and adding modern features like the CI-V computer control. Improve Receiver Sensitivity

Tools You Will Need

Before you attempt any mod, assemble this toolkit:

  • Soldering station (fine tip, temperature controlled)
  • Desoldering pump or braid (vias on the M700 are fragile)
  • ESD-safe tweezers
  • Digital multimeter
  • 50-ohm dummy load (minimum 150W)
  • RF wattmeter (Bird 43 or equivalent)
  • Service manual (PDFs are available on Repeater-Builder or Mods.dk)

Add a Rear-Panel ACC Jack

The M700 lacks a standard 6-pin accessory jack for amplifiers or TNCs.

  • Mod: Install a DIN or SO-239 on the rear panel connected to:
    • SEND (PTT line)
    • Audio out (from detector)
    • Mod in (balanced modulator input)
  • Use case: Connect to an SDR panadapter or a linear amplifier.

1. The "Must-Have" Mod: Full Frequency Coverage (MARS/CAP Mod)

Goal: Transmit on 160m through 6m amateur bands (1.6–30 MHz continuous).

Most M700s are software or hardware limited to marine bands. Here’s how to open them.