Icom | M700 Mods

Achieving clear audio in SSB (Single Sideband) mode is a priority for operators using the M700 in various radio services. Enhancing the modulation depth and optimizing the speech processor are common technical interests.

With careful attention to technical detail and regulatory requirements, the Icom IC-M700 remains a durable and capable platform for HF communication. By expanding its frequency capabilities and integrating modern digital interfaces, operators can extend the utility of this classic marine transceiver for years to come.

: The standard IC-M700 is an Upper Sideband (USB) and AM/CW only radio. Amateur radio bands below 10 MHz (like 40 meters and 80 meters) traditionally use Lower Sideband (LSB). To operate on 40m and 80m ham bands, you must either operate on USB (which is legal but rare for voice) or install a third-party LSB modification kit, which involves adding a custom BFO (Beat Frequency Oscillator) crystal circuit.

This guide covers the most common Icom M700 modifications, focusing on general coverage transmit expansion, audio improvements, and operational enhancements. icom m700 mods

Now that we've covered the why, let's explore some of the most popular Icom M700 mods:

The Ultimate Guide to Icom IC-M700 Modifications The Icom IC-M700 is a legendary marine HF transceiver. Built like a tank, this commercial-grade radio is famous for its reliability. While designed for maritime use, many amateur radio operators and shortwave enthusiasts use it on ham bands.

The Icom IC-M700 is a legendary marine HF (High Frequency) transceiver. Built like a tank, this commercial-grade radio is famous for its reliability, powerful 150-watt transmitter, and excellent receiver. While originally designed strictly for maritime use, radio amateurs, shortwave listeners, and preppers frequently modify the M700. These modifications expand its frequency range, add features, and optimize it for amateur radio (HAM) operations. Achieving clear audio in SSB (Single Sideband) mode

The frequency restrictions on the IC-M700 are controlled by a physical diode matrix located on the (sometimes referred to as the Display or Matrix Unit behind the front panel).

After removing the diode, perform a factory reset by holding down the clear/reset button combination while powering on the unit to initialize the new frequency boundaries. 🎙️ 2. Audio and Microphone Enhancements

Out of the factory, the IC-M700 restricts transmitting to specific marine bands. Opening up the radio for general coverage transmit allows you to use it on the amateur radio bands. To operate on 40m and 80m ham bands,

: Access the top section of the radio chassis and remove the shielding cover over the digital control circuitry.

To give your voice a warmer, more natural broadcast quality, you can modify the microphone pre-amplifier stage on the .

Find the matrix of small switching diodes (usually labeled in the service manual schematic as the programming matrix).

: The original HM-28 microphone is often replaced with the modern HM-114 . Note that this requires replacing the internal connector (53) on the MIC-C-UNIT board.

: Expanding coverage to include 10/11 meters requires hex editing the SRAM contents (reversing frequency data) and retuning the VCO. Audio & Hardware Upgrades Speech Compressor