By viewing this web page on a desktop PC your computer is transmitting a radio signal in morse code.
The background image is an animated GIF which when displayed results in the monitor's HDMI/DVI cable radiating at a specific set of frequencies depending on what video mode you are using.
You will find the signal in SSB/CW modulation between 250-380MHz as long as you are within 10 metres of the computer. For best results make the web browser go fullscreen.
On my monitor (2560x1440 @ 60Hz) the signal can be heard best at ~362.5MHz at ~362.4MHz.