A 2 4GHz High Power Audio Video Link

November 28, 2016

Forget about flea power A-V links. This one has an output of 0.5W for a range of about 200 meters using simple "whip" antennas.

You will have seen adverts for devices of this type - they've become quite popular in recent years.

Operating on a frequency of 2.4GHz (that's 2,400,000,000Hz for the uninitiated!), most have about 10mW or so output and while they work well over a short range, the range is limited by the low power.

This design has much higher power - around 0.5W output, in fact. So as you might expect, the range is very significantly extended. With the simple coax cable "whip" antennas shown here, the range is reliably 200m or more. But if you use a simple dipole antenna, you could expect much more range - maybe 10 times or more.

Perhaps a word or two about how and why this is possible is in order. It is sometimes difficult for people to understand how changing antennas can give longer range.

The simplest analogy I can think of is using your own voice. You can talk at a certain level and you'll be heard up to a certain range. You can shout, and of course you'll be heard by people further away. You're increasing the power of your voice.

Or you could cup your hands around your mouth and project your voice in a certain direction. Those off to the side won't hear as much (if at all) but those in the direction you're projecting will hear much more.

That's the equivalent of using a directional antenna. You're concentrating power in one particular direction at the expense of other (unwanted) directions.

If you replaced your hands with a long length of pipe, those to the side would hear little, if anything. But those at the other end of the pipe, even over a very much longer distance, could possibly hear you.

That's the equivalent of using a highly directional antenna. Very little energy is radiated in any direction except the one you want.

OK, now that we know how to get longer range by increasing power and/or using directional antennas, let's get back to the Audio/Video .