Video distribution applications always come down to a numbers game. To effectively send a picture from point(s) to point(s), you will need to know the number of video sources you have to distribute, and the number of displays.

You’ll need to know whether the system will always send the same image to every display (think digital signage, for example) or whether every display must have access to every source.

Leave room in the budget for control systems if clients wish to manipulate with ease what source or channel they are viewing, especially on a large scale.

Here’s a look at three common video distribution pitfalls and how to overcome them.

Trip-Up: Single Source, Many Displays
If the system is configured in which one source will be seen simultaneously on many displays, you have options that are determined by the usual suspects: what type of signal you have, how many and what type of displays you wish to feed, how far those displays are from the head end, who will be running the system, and what type of cabling is in place.

In many of these instances, a simple distribution amplifier can be specified. If you are sending a simple component or VGA type of signal, you could use either a Cat 5 cable with baluns or a mini-RGB coaxial wire through that D/A and be good to go.

If the source is HDMI, you may find yourself checking your measurements multiple times to ensure that the baluns will work for your application. Issues such as the number of Cat wires, whether you’ll need 5 or 6, or shielded 6, are determined by which balun you deploy. For longer runs of HDMI, you’ll likely specify fiber and appropriate ancillary hardware.

Trip-Up: Matrixing Multiple Sources, Multiple Displays
In situations where there are many sources and many displays, you’ll end up considering some sort of matrix switch mechanism. Again, the type of signal will determine the specifics of the matrix, as will the number of sources in, and the number of displays that you want to feed. Keep in mind that you can make a hybrid system by deploying both a matrix and distribution amps on the outputs of the matrix, so that groupings of displays will show different content.

Trip-Up: Modulating Multiple Sources, Multiple Displays
Back in the good old days, modulation was an inexpensive way to achieve video distribution to displays with tuners onboard. By placing a modulator on each video source, you could feed lots of displays, deploying additional combiners, amplifiers and splitters as the scope of the project increases. Those modulators delivered a low-definition NTSC signal, which frankly can look nasty on a high-definition display.

Lately, a select few manufacturers are offering modulation on the QAM digital cable band. Concerns with those include whether the display has a QAM tuner (most do, but assume nothing) and the type of signal you wish to modulate. ZeeVee, for example, will only work with a component video or VGA style of signal, so Blu-ray players with only HDMI outputs are out of the picture. The advantages to modulation carry over from the past, which include lower wire costs (a single line of coax), ease of adding more displays through splitters and amplifiers, and easier local control or what signal is being viewed through tuner selection.

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Fred Harding

Fred Harding handles technical sales and design at Capitol Sales.

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