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Bigbio2002
Asked: 2012-02-22 09:04:03 +0800 CST

How to define a "challenging RF environment"?

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I'm shopping around for some new Wi-Fi routers, and the Cisco Aironets look pretty good. There are some differentiating features between the models; in particular, the 1260 is designed for "challenging RF environments" (via the ability to add antennas, apparently), versus the 1140.

Now, my office is in NYC, which is heavily congested in just about every imaginable way. My iPod picks up ~10 WiFi SSIDs near the main access point, and you can assume that everybody and their brother is using their iPhone along with god-knows how many other devices, on both WiFi and 3G/4G. On a worst-case scenario, let's say that I'll have 50-100 people connecting to this particular access point. Does this constitute a "challenging RF environment", or is this a fairly typical, non-extreme load? More practically, does this justify the additional expense of getting the 1260?

Note: there are 3 other access points at various places in the building, but the one in the lobby will be the most heavily-used one due to its location.

wifi access-point

1 Answers

  1. Best Answer

    It sounds to me like their definition of a "challenging RF environment" refers to the need to use directional antennas to limit the propagation of signal in unwanted directions or to focus reception on a narrow physical area where clients will be located.

    I suppose you could try to do something with directional antennas to direct your radio(s) into your space and to limit radiation into areas where you won't have clients. I'd rather just buy a radio that does that for me (Xirrus and Ruckus are a couple that I'm familiar with that have such functionality "out of the box"-- there are probably others but I haven't kept up). You're going to have to do some experimentation with antennas (and likely a spectrum analyzer) to figure out the best way to do this yourself. There are a couple of posts on the Server Fault blog that can give you some basics about RF.

    You're going to have a really hard time getting the upper end of your intended range of 50-100 clients to associate with a single radio, no matter how expensive it is (especially in an environment where the band is noisy already). You're better off getting a couple (or three) radios and deploying them in a physically distributed manner than trying to cram everybody on one radio.

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