VGA Video Breakout Boxes

Overview

Video breakout boxes are handy little tools for experiments involving VGA video signals.  These breakout boxes will come in handy if you are ever experimenting with "van Eck Phreaking."  This is the infamous, and often misunderstood, method where you try to recreate a computer monitor's display by intercepting the RF "noise" the monitor or the video cable and card are radiating.  To help recreate these images, you'll need to use a VGA video breakout box which will allow you to insert your own horizontal and vertical video synchronization signals, along with your newly recovered video input signal.

Construction Notes & Pictures

Parts overview.  You'll need a metal outlet box and matching metal cover plate, some DB-15 connectors (both male and female versions), and a bunch of BNC connectors.  Purists should use 75 ohm BNC connectors, but the regular 50 ohm version will work fine.  You'll also want some 3/8-inch solder lugs for the BNC connectors.

Salvage an old VGA video monitor for a source of small-diameter 75 ohm coaxial cable, as shown in the picture.

To mount the DB-15 connetors to the outlet box, you'll need to file little notches on the side of the knock-out plug hole.  The notches will allow the connector's mounting hardware to secure the connector.  You may need to place washers on the hardware if the notch is too big.  Also be sure the notches are deep enough so the mounting hardware isn't fixed at an angle, which can block the insertion of the video cable.  Use a little Loctite on the nuts to prevent loosening the DB-15 when you disconnect the video cable.

Wire up the first breakout box as shown in the schematic.  Yes, it will be a pain.  Remember to tie all the ground leads together, including a ground wire to the metal case.  Note the green ground screw which has a wire going to the DB-15's common ground.

Drill five 3/8-inch diameter holes in the metal cover plate in a pattern you wish.

Connect the video and synchronization lines as shown.  The video signals will need their integrity maintained by using coaxial cable and a good ground connection to the BNC connector.  The horizontal and vertical synchronization lines can just be single wires.

Completed case overview.  Use an extension video cable to connect the breakout box to the video card.

For the second breakout box, we'll do things a little differenly.  This version will allow you to insert your own video and synchronization signals.  The toggle switch selects between using an external video card to generate the horizontal and vertical synchronization signals or injecting your own.  Be sure both DB-15 connectors share a common ground.

The BLUE video input line is terminated with a 75 ohm resistor.  The other video inputs are left unterminated.

Completed case overview of the second version.

Schematics