Vhf Morse Transmitter Monitor

The VHF Monitor RF Transmitter is a browser-based experimental tool that converts an ordinary computer display into a short-range VHF Morse code transmitter .

Modern video pipelines are not purely optical; they are high-speed digital electronics operating at high frequencies. This project exploits Unintentional Electromagnetic Radiation (EMI) to broadcast readable RF signals.

When the screen displays a plain black or static background, the signal current across the video cable remains relatively uniform.

However, when the application renders an alternating $1 \times 1$ pixel pattern (alternating black #000000 and white #FFFFFF pixels side by side), every adjacent clock cycle forces the display interface serializer (TMDS or FRL in HDMI; Main Link Lanes in DisplayPort) to toggle its voltage state rapidly.

This maximum state toggling induces a strong electromagnetic field at the exact pixel clock frequency ( 148.500 MHz ), broadcasting an RF carrier wave into space.

Carrier ON (Mark): The application renders a high-contrast alternating pixel pattern across the entire screen canvas. The video line serializer fluctuates at maximum capacity, emitting strong RF interference.

Carrier OFF (Space): The canvas switches instantly to solid black ( #000000 ). Clock transitions drop to minimal baseline noise, collapsing the radiated RF output.