topic Re: Directional/Patch Antennas in Wireless

Directional/Patch Antennas

paul_erion — Sun, 04 Jul 2021 00:16:29 GMT

I'm wondering how directional a patch antenna is ... for example, if I mount a directional/patch antenna (for a 1252) in the middle (horizontally) of a 60' wall, will there be signal at the endpoints of the wall?

Thanks,

Paul

Re: Directional/Patch Antennas

Leo Laohoo — Fri, 06 Mar 2009 23:52:41 GMT

Hi Paul,

Have you tried Cisco Aironet Antennas and Accessories Reference Guide (http://www.cisco.com/en/US/prod/collateral/wireless/ps7183/ps469/product_data_sheet09186a008008883b.html) or the Cisco Aironet 2.4 GHz and 5 GHz Antennas and Accessories (http://www.cisco.com/en/US/prod/collateral/wireless/ps7183/ps469/product_data_sheet09186a008022b11b.html)?

Hope this helps.

Re: Directional/Patch Antennas

paul_erion — Sat, 07 Mar 2009 00:13:46 GMT

Thanks for the reply ... yes, I did look at those, and they were helpful. Unfortunately, I'm not quite sure how to read all of an antenna's specs (i.e., how to translate them into the specifics of my question). In particular, I'm not sure how to interpret the radiation pattern graphs, and how I can apply them to the specifics of a building/structure.

Re: Directional/Patch Antennas

Scott Fella — Sat, 07 Mar 2009 02:34:40 GMT

There are alot of site out there with the information you are looking for. Take a look at this:

http://www.astronwireless.com/topic-archives-antenna-radiation-patterns.asp

Re: Directional/Patch Antennas

scottmac — Sat, 07 Mar 2009 04:31:36 GMT

If the patch antenna says it covers 180 degrees, then the wall's end wold be covered.

The diagrams are showing you what the pattern looks like from the top, and what the pattern looks like from the side.

Think of what a doughnut looks like from the top (a large circle) and what it looks like from the side (a smaller circle).

The limits of the diagram are usually 6db, corresponding to ~25% of the original radiated power.

Good Luck

Scott

Re: Directional/Patch Antennas

paul_erion — Sun, 08 Mar 2009 20:41:53 GMT

Thanks for the pointer!

So if I've understood what's going on (which is not a safe bet), by looking at the "Antenna A Elevation and Azimuth Pattern" for the AIR-ANT2430V-R antenna (http://www.cisco.com/en/U/docs/wireless/antenna/installation/guide/ant2430v.html) I could figure that the antenna shows a loss in the elevation plane of approximately 7 dBi at 120 degrees at 30 meters. Am I close?

Thanks,

Paul

Re: Directional/Patch Antennas

Scott Fella — Mon, 09 Mar 2009 15:49:54 GMT

That is correct. The low points between a wave is considered null and is your weakest signal. Again, this antenna is an omni directional, so depending on your environment, it can change. Distance also varies depending on your environment and what db you require.