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New Member

Coverage of an AP 1/2 mile away

I have a house that is 4/10's of a mile from my main building that needs coverage. I was told that I could get coverage out to that house by placing a 13.5 dBi Yagi antenna on an Access Point back at the main building and just shoot it in the direction of the house.

I was then told by someone else that the client Cards aren't strong enough to talk back to the AP at that distance, and that I needed to look at bridging instead.

Which way should I go? Thanks for your help.

6 REPLIES
New Member

Re: Coverage of an AP 1/2 mile away

You would definitely be best served by bridging this. I would recommend using the BR350's to bridge the link between the main building and the house. Keep in mind that radio line of sight is required for optimal performance.

New Member

Re: Coverage of an AP 1/2 mile away

You could buy a client card that has a connector for an external antenna, and attach a yagi to that, if you're only supporting one user.

For up to 8 users, you could use a workgroup bridge and attach the same antenna.

A 13.5 yagi is likely overkill for a half mile link. An 8.5 dbi patch likely work. You should have an actual survey done by a professional that's done P2P links.

You don't require bridging. Cisco bridges compensate for 802.11b timing limitations that are incurred over distances past 1 mile, which doesn't apply here.

New Member

Re: Coverage of an AP 1/2 mile away

The 13.5dBi Yagi would give you a Fade Margin of 17dB (at 11Mbps) if the client had a direct line of sight. That's pretty good, but you're probably going through walls, so more gain would be better, and the best place to add it would be at the client. An antenna in the window would work well.

More importantly, if you are talking about connecting to an existing AP, you can't just add an antenna without losing signal strength in the original coverage area.

We have an antenna that would work well at the remote site for under $50. It's 19dBi, which would give you a lot of strength back to the central site - probably enough to get to an existing AP indoors.

Matthew Wheeler

Blue Modal

New Member

Re: Coverage of an AP 1/2 mile away

Matt,

So, by adding another client, the AP's coverage over its existing range diminishes? I didn't know that. Can you explain? Thanks.

New Member

Re: Coverage of an AP 1/2 mile away

Adding an *antenna* would cut the power to the first antenna by half.

The AP output is 20dBm, using a 2:1 splitter cuts that to 10dBm per antenna, then add the gain of the antenna to get final output power.

Adding clients won't impact the coverage area.

New Member

Re: Coverage of an AP 1/2 mile away

OK, gotcha. I didn't pick up on the splitter.

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