What does omni-directional mean?
Omni means all, or every. So omni-directional means that the antenna sends
information in every direction.
What does the antenna do?
Omni-directional antennas are used in many applications, but until Nomad, they
were the only way a moving robot could send information. Nomad uses an
omni-directional antenna to send and recieve low level communications, such as
commands. It cannot use this antenna to send complex pictures from the
panospheric camera because it
cannot send enough information quickly enough with it. But the
omni-directional antenna is still the robots main communication for basic
Think of it like this...
An omni-directional antenna broadcasts in all directions, outward from the
antenna, so only one part of the signal reaches the reciever, the rest is just
sent out into space. The concept is easy to understand if you use a picture of a fountain as an example. In the picture to the right you can see how the
water is spraying in many different directions.
Image taken from
Compare this to the picture of the waterslide on the left. All of the water in this picture is all falling inthe same direction, so the stream of water is larger and stronger.
Want to see how it works? Try it yourself...
Next time you're in the bathtub try this:
Pretend that every drop of water from the faucet is a piece of information,
just like the kind of information that the omni-directional antenna would
receive. Which time did more information reach your hand? If you aren't sure,
just think about which time your hand got more wet.
- First, run the water and put your hand under the faucet as close to the
drain as possible.
- Second, put one hand under the faucet again, but this time place it
right under the faucet to the water sprays out in all directions.
Put your other hand someplace where the spray is hitting it.
When you made the water spray, you were actually seeing how the
omni-directional antenna works. If the information is sent out in more
directions, less information will reach the receiver.
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Animated waterslide image taken from TODAY magazine
Last Modified on: Thu Jun 12, 1997