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Can someone direct me to a (simple?) guide to understand what are the azimuth and elevation radiation patterns?

I understand they are how the radio signal goes out from the antenna, but what view is which (overhead, side, etc)? And how do they relate to the E-Plane and H-Plane (or are they two names for the same thing)?

Azimuth is the top down view of the radiation pattern which is spread out horizontally (H-plane for horizon)

Elevation is the side view of the antenna and its vertical radiation pattern (E-plane is for Elevation)

Someone please "check my math" on this, I am not cert'd yet. (I have however spent my every waking moment for the past 8 weeks with my nose to the book)

You will find this information on pages 105-106 of the newest CWNA study guide. Kory is right in his description. Typically, it is succeinctly described like this:

Azimuth = top down view = h-plane
Elevation = side view = e-plane

Tom

Radiation and Elevation charts can be very useful. However, I have found Front-to-Back ratios more useful in the (indoor) client device testing that I perform.

One warning I would like to make is that you have to be careful reading sellers/manufacturers plots. Some of them are only "the artists interpretation", are not made with real measurements, and can be totally misleading.

Cisco has some good data and examples of legitimate plots. See for example the last sections of:

http://www.cisco.com/en/US/prod/collateral/wireless/ps7183/ps469/product_data_sheet09186a008008883b.html

These charts stumped me for a long while. Its not something i grasped straight away.

I read a whitepaper or blog about this and it helped me understand it a little bit. I think the link was posted on this forum...it was an Apple that was chopped horizontal and veritcal.

anyway, while I need to hit the CWDP or CWNA book again on this, I still sometimes find it hard to understand how to measure the beamwidth from an Azzi chart.

On a traditional chart, where the outer ring of the polar graph corresponds to 100% signal (regardless of the actual antenna gain or signal strength), the maximum gain measurement should be very near or touching the outer ring of the graph.

Find this point on the graph, and then follow the [u]actual data[/u] plot back in both clockwise and counter clockwise directions until the measurement (on each side) reaches 3dB down from the maximum (100%) reading.

This measurement will typically be symmetrical about the maximum reading on the outer ring. Obviously properly annotated polar plots help the analysis.

Let's say, for example, that the degrees read clock-wise and counter clockwise are +15 and -15 degrees. The difference between these two readings, ie 30 degrees, is what is reported as the (3dB) beamwidth.

An obvious example, is a good dipole antenna's Azimuth chart. The plotted data will, pretty much, be at the outer edge of the polar chart all the way around. In this case we would say that the answer is 360 degrees.

I have heard that values other than 3dB (ie half the power) are also used, but I have never seen any.

Hope that helps.

PS: Here is more information:

http://www.phys.hawaii.edu/~anita/new/papers/militaryHandbook/antennas.pdf