Kenwood Tkm-707 — Mods

You can now legally operate on 160m through 12m. The radio is still limited to 150W PEP, which is perfect for mobile or base use.

Ultimate Guide to Kenwood TKM-707 Modifications The Kenwood TKM-707 is a legendary HF marine transceiver known for its commercial-grade build quality and reliable performance. While originally designed for marine SSB frequencies, amateur radio operators and shortwave enthusiasts frequently modify this radio to expand its capabilities. Direct Frequency Entry and Transmit Expansion

: Always use a grounded soldering station and an anti-static wrist strap when working on internal boards to avoid damaging sensitive logic circuits. Kenwood Tkm-707 Mods

The Automatic Level Control (ALC) is set aggressively for marine use. Locate internal potentiometer VR2 on the TX board to back off the ALC compression for a more natural voice peaks. Cooling and Duty Cycle Optimizations

Open the radio up and locate jumper JP5 on the main control board (near the front panel ribbon cable). On most units, removing this jumper opens the TX from 1.6 MHz to 24 MHz continuous (some later models require a diode matrix change). You can now legally operate on 160m through 12m

PA transistors (2SC2879, etc.) are easily destroyed above 180–200W. Not recommended.

| Diode | Marine Stock (Typical) | All-Band Mod | |-------|------------------------|--------------| | D5 | Installed | | | D6 | Installed | Remove | | D7 | Empty | Add | | D8 | Installed | Remove | | D9 | Empty | Add | | D10 | Empty | Add | | D11 | Installed | Remove | | D12 | Empty | Keep Empty | Locate internal potentiometer VR2 on the TX board

Before diving into modifications, it's crucial to understand the TKM-707 in its stock form. Built for the marine environment, it features a rugged aluminum chassis and stainless steel exterior, with a cooling system designed for extended high-power transmission.

8-pin DIN (ACC) – no direct FSK/FM input.