Some operators require an even more extensive frequency expansion, particularly for military auxiliary services like MARS (Military Auxiliary Radio System) and CAP (Civil Air Patrol). While less common for the TKM-707 than for newer radios, this mod is mentioned in modification databases. Typically, such mods involve more complex steps, such as removing a specific chip resistor or manipulating a specific colored wire in the wiring harness. As with the ham band mod, any attempt at this should be made only with the full service manual and by those with advanced soldering skills.
What is stamped on your unit's rear ID plate?
The Kenwood TKM-707, with its rugged stainless steel chassis and high-stability OCXO (Oven Controlled Crystal Oscillator), is a fantastic platform for modification. Unlocking its VFO mode, expanding its frequencies, and fine-tuning its performance transforms it from a dedicated marine radio into a powerful ham radio transceiver. By following the procedures laid out in its service manual and the wisdom shared in forums like mods.dk and hellocq.net, you can breathe new life into this classic and enjoy a genuinely unique and high-performing station. kenwood tkm707 mods
The Kenwood TKM-707 is known to be a powerhouse. While factory rating is 150W PEP (Peak Envelope Power), many users report adjusting it to reliably produce between 180 and 200 watts. The power is adjustable in three pre-set levels (LOW, MID, HIGH) using the keypad. You can fine-tune this output by locating a 50kΩ SMD (Surface-Mount Device) potentiometer on the main board, often labeled with the text SSBPWR next to it.
Default = 100 channels. To get 200:
This configuration enables high-power transmission and allows operation in both VFO and Memory modes.
Optimal performance depends heavily on the antenna setup. A common "mod" to improve poor reception involves ensuring the 17 ft whip antenna has a solid connection to a copper ground plane strip, often connected through hull fittings to the engine block to minimize RF interference. Key Technical Specifications Some operators require an even more extensive frequency
+--------------------------+ +-------------------------+ +---------------------+ | Kenwood TKM-707 Rig | Control | MAT-100 / KAT-1 Tuner | Hi-Volt | End-Fed Wire / | | (Modified for VFO/HAM) |=========>| (Antenna Coupler Unit) |=========>| Long Whip Antenna | | [50-Ohm Coaxial Out] | Cable | [RF Impedance Match] | RF Out | [Wideband Tuning] | +--------------------------+ +-------------------------+ +---------------------+ || || Heavy Copper Strap \/ +-------------------------+ | Dedicated RF Ground | | (Hull / Ground Rod) | +-------------------------+ Kenwood TKM-707 SSB Radio Telephone - Cruisers Forum
Note: Frequencies will now typically expand to cover 1.6 MHz through 30 MHz continuously for transmit and receive. Hardware and Audio Upgrades As with the ham band mod, any attempt
requires a high current draw when delivering its full 150-watt output. Ensuring that the primary power lines use high-gauge copper wiring and modern, low-resistance fuse blocks helps maintain a stable 13.6 VDC. All DC power modifications must follow standard electrical safety codes to prevent voltage drops or thermal hazards during peak operation. Optimizing the Antenna Tuner Interface To effectively utilize a modified Go to product viewer dialog for this item.
In the mid-90s, Kenwood was a dominant force in amateur radio (specifically the "TS" series) and commercial land-mobile radio (the "TK" series). The TKM-707 was a 2-meter (144–148 MHz) FM transceiver.