Kenwood Tkm-707 Mods

The TKM-707 is excellent for digital modes because it has a stable oscillator. However, you need a proper interface (like a SignaLink USB or DigiRig).

SSB radios are highly sensitive to grounding. A common enhancement to any installation involves adding a dedicated copper ground plane or counterpoise. This helps prevent RF feedback from interfering with the radio's control logic and improves the overall efficiency of the antenna system. Essential Technical Specifications Specification Output Power 150W PEP (High), 50W (Med), 25W (Low) Receiver Range 500 kHz to 30 MHz (General Coverage) Modes J3E (SSB), H3E (AM-compatible), CW Power Requirements 13.6 VDC ±15% (Up to 30A during transmission) Operational Safety and Documentation Kenwood Tkm-707 Mods

This is the most popular mod for the TKM-707. It opens the transmit capabilities to cover the entire HF spectrum (1.6 to 30 MHz continuous) rather than just marine channels. This is often called the because it allows operation on Military Affiliate Radio System frequencies. The TKM-707 is excellent for digital modes because

| Issue | Likely Cause | Solution | | :--- | :--- | :--- | | | You removed the wrong diode. The CPU lost its band table. | Re-install original diodes. Refer to service manual for default config. | | No TX on 10m (28 MHz) | Radio’s LPF board doesn’t include 28 MHz by default. | You need to swap relays on the LPF board or add a 28 MHz external LPF. | | LSB sounds "Donald Duck" (pitchy) | The crystal mod isn’t frequency accurate. | Adjust the trimmer capacitor on the LSB crystal circuit. | | Display dim or flickering | Stock EL backlight failing. | Replace with LED strip mod (12V white LED strip cut to size). | | No output power | Dirty relay on the LPF board. | Tap relay RL1 gently with a screwdriver handle. Desolder and clean if persistent. | A common enhancement to any installation involves adding

If you are performing these yourself, it is highly recommended to reference the Kenwood TKM-707 Service Manual for exact board layouts and component locations.