Broadcasts real-time pictures of a VGA video monitor to a remote location. Useful for covert interception of a video monitor, provided the target doesn't recognize the damn microwave radio transmitter sitting next to their computer.
Uses a common Zenith Presentation series VGA-to-TV converter, or homebrew Analog Device AD725 VGA-to-NTSC adapter, placed inline with the TARGET's video monitor cable. This current setup only works on monitors operating in 640x480 or 800x600 pixel resolution with a 60 Hz vertical refresh. Other VGA-to-TV adapters will probably have better specifications.
For the receive side, use a standard C-band satellite receiver, without the block downconverter, to receive the 1.2 GHz signal. The baseband video output of the satellite receiver can then be run into a TV or VCR video input.
Transmitting Higher Resolution SVGA Signals
It is possible to transmit higher resolution SVGA signals, but the process can be quite touchy. Basically what you do is tap the individual Red/Green/Blue signals going to the TARGET monitor and transmit them via a very wideband microwave FM transmitter. You then receive and demodulate these signals and combine them with your own horizontal and vertical synchronization signals. The problem comes with generating the exact horizontal synchronization signal. This isn't possible without a precision (sub-hertz) signal generator. You'll also need three separate transmitters, one for each color, for an exact re-creation of the TARGET's monitor. A single transmitter, for a single color, will work well for experimenting.
- Analog Devices AD725 RGB to NTSC Encoder datasheet (355k PDF)
- van Eck-style Radiation Interception Experiments
- Electromagnetic Radiation from Video Display Units; An Eavesdroping Risk? Wim Van Eck (720k PDF)
- VGA to PAL and NTSC converter by Tomi Engdahl
- Bugged ATI Mach32 Video Card - Picture 1 (using Tomi Engdahl's sync circuits)
- Bugged ATI Mach32 Video Card - Picture 2 Composite video output (to the transmitter) is the small 1/32" jack on the card edge metal thing. +5 VDC is tapped from the input filter capacitor, and the 14.318 MHz clock is tapped from one side of the card's crystal.