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The Icom IC-M700 Go to product viewer dialog for this item. is a classic marine SSB transceiver that has found a second life among amateur radio operators due to its rugged build and relatively low cost on the used market. While originally restricted to marine frequencies, several hardware and software modifications can unlock its full potential for ham radio and general coverage use. Core Performance Modifications
Elliott Liggett’s GitLab Repository: A modern resource focusing on making the M700 more user-friendly for ham use, including video demonstrations of active mods. icom m700 mods
The Icom IC-M700 is a classic marine SSB transceiver that is highly popular for amateur (Ham) radio conversion. Modifying it typically involves unlocking transmit frequencies, expanding memory, and improving audio for non-marine use. 📻 Core Modifications for Ham Radio The Icom IC-M700 Go to product viewer dialog for this item
The Problem: The audio path uses small-value capacitors that roll off frequencies below 300 Hz. This kills bass response, making your receive audio sound "tinny." Cooling and longevity tweaks
Maintenance/Modification:
10-Meter Extension: Standard jumpers typically limit the radio to ~23 MHz. Reaching the 10-meter band (28 MHz) usually requires more complex modifications to the band-pass filters and oscillators.
But Eli was greedy. He wanted the secret whispers, the ones that lived in the noise floor below 500 kHz. The M700’s standard receive range stopped at 500 kHz. "Too much risk of broadcast interference," the service manual stated primly. Eli scoffed. He found the schematic, traced the PLL loop, and identified the two surface-mount resistors that formed the frequency divisive voltage divider. A night's work with a multimeter and a resistor substitution box gave him the values. Remove R178. Replace R179 with a 22.1k. He did the swap with tweezers and held his breath. He powered it on, keyed in 472 kHz—the 630-meter band. The waterfall on his SDR Play, connected to the M700’s IF out, lit up with a low, grumbling auroral glow. It worked. The old marine radio could now hear the songs of the earth itself: the rasp of lightning from a storm off the Azores, the rhythmic pulse of a Russian time signal, the eerie, unmodulated carrier of… something else. He never found out what.