Wireless VGA Adapters, how they work and what makes a good one

 

 

Wireless VGA

It seems that everything is going wireless these days. Wireless connectivity provides the advantage of simple connections, without any of the problems associated with having to fight with a rat’s nest of cables. Whether you’re dealing with a computer or an entertainment center, the number of cables that are involved in hooking things up can be a nightmare.

There are many times in business environments where a computer needs to be connected to a video projector or a large-screen HDTV. This is most often for showing presentation, although it can also be needed for showing training or marketing videos. Making this connection either requires the computer be co-located with the TV or video projector, or running cables across the conference room. There are times when it would be much more convenient for the presenter to have their computer with them, while the presentation is run on a HDTV across the room.

Wireless VGA adapters are made to accommodate this need. They are really not intended for home theatre use and some models are actually prohibited from use in homes. While they would function in the home, there’s a good possibility that the frequency they transmit on would cause interference with other devices.

How Wireless VGA Adapters Work

While some computers have switched over to DVI or one of the other new video connection formats for their video connection, VGA is still considered standard. Most new computers and all older computers have a VGA connection for carrying video signals to a monitor.

The VGA standard is an old one, but it has been updated a number of times. Due to this, the old resolution standard of 640 x 480 pixels is something that is largely ignored today. Most modern computers use one of the newer formats:

Format

Resolution

Aspect Ratio

SVGA

800 x 600

4:3

XGA

1024 x 768

4:3

SXGA+

1400 x 1050

4:3

UXGA

1600 x 1200

4:3

WXGA

1280 x 800

8:5

WSXGA+

1680 x 1050

8:5

HD 720

1280 x 720

16:9 (widescreen)

HD 1080

1920 x 1080

16:9 (widescreen)


Although the HD formats are normally thought of as only being used for HDTV, they are also used for computer monitors as well. Today’s televisions and computer monitors are more generic devices, able to connect to a variety of equipment. So, it is not unrealistic to use a HDTV as a computer monitor, have a computer monitor that is formatted for HDTV, or even connect a computer monitor to a BluRay device for watching a video.

Like many other wireless devices, wireless VGA adapters have to convert this input signal into something that can be transmitted over the airwaves. In the process, some covert the video to a lower resolution format, reducing the crispness of the image. So, this is one important thing to look at when looking at a Wireless VGA device, especially if the detail is important in your presentation.

Wireless VGA devices consist of two pieces, one that connects to the computer’s VGA port and the other which connects to the HDTV or video projector. They communicate with each other at 2.4 GHz, in the upper end of the UHF (ultra-high frequency) range.

There is a variant of this device, which uses a USB dongle to connect to the computer, rather than connecting to the computer’s VGA port. While this works well and is convenient, these devices typically can’t broadcast video at the highest resolutions.

What to Look for in a Wireless VGA Device

Not all wireless VGA devices are created equal. There are a wide range of devices out there, which all operate a little differently. More than anything, when looking at these devices, you need to be sure that you read the specifications carefully, in order to make sure that the device you are buying will provide the type of performance you need.

  • Input Format – Most all of these devices will specify either VGA or USB connection. However, the important thing is what input resolution it will accept. If the input resolution is less than your computer is using, the image won’t appear as crisp and clear, especially when blown up on a HTDV.

  • Output Format – Different output formats are available, including composite video, S-video, VGA, and component video. This is important, as it affects the output resolution.

  • Output Resolution – This is the hardest specification to find, but is the most important. Some will only provide a resolution at the level of the old broadcast TV standard, which is the same as the original VGA. If you have detailed diagrams or text, it may not be highly readable.

  • Channels – By providing various different frequencies manufacturers give you the option of changing frequencies to avoid interference.

  • Operating Range – The maximum operating range of these devices can be anywhere from 30 to 150 feet. While the longer range would seem to be the better option, it might cause interference if several devices are used in the same facility.

  • Audio Connections – The VGA format does not include audio. However, some VGA wireless devices do allow audio connection, via RCA jacks, to be transferred to the remote video device. If the device is being used for video or the presentation includes sound effects, this would be needed.

Some Wireless VGA devices have additional features, such as controls for brightness, contrast and hue, scalable sizing and area zoom. Area zoom allows you to zoom in on part of the image, magnifying that to cover the whole screen.

Rich Murphy