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Site surveying with commercial software
Radio frequency spectrum analyzers
- Measure for excessively noisy 2.4 and 5 GHz using a spectrum analyzer and get rid of them. If you can't afford one, you can still do the following to minimize interference issues.
- Stick with newer 5.8 GHz digital spread spectrum cordless phones.
- Stick with wired video cameras. For any fixed devices that don't need to move around like a laptop or PDA, CAT-5 cabling is the best way to go because not only does it transmit data, but also electricity to power the device, so that you don't need to use an AC adapter and a thick power cord.
- If you must use a wireless camera because it's not feasible to run CAT-5 cabling, use an 802.11 camera (preferably 802.11a if possible) because they use less radio spectrum.
- Analog 2.4 GHz cordless phones are also notorious for being spectrum hogs, and cordless 2.4 GHz analog video cameras are also in the same category.
- In most cases, you'll find that newer, well-made microwave ovens will produce less noise than an older model that can easily overwhelm a 802.11 b/g WLAN with sheer power.
- Bluetooth devices can also cause interference in the 2.4 GHz range, but their power levels are usually limited especially with the newer Bluetooth 1.2 standard that's designed to play nicer with 802.11.
NetStumblerThis gallery is also a TechRepublic article.
NetStumbler is an excellent free tool for performing WLAN site surveys (note that NetStumbler is not useful for penetration or security testing, but that's not in the scope of this article). It won't give you all the polished reports, and it takes a little extra work to come up with the results. However, with a little help from this tutorial and our downloadable Excel Macro tool, this is an excellent free solution.
First, you simply walk around the building with a laptop running NetStumbler on a predetermined path with sampling points where you want to measure the RF signal levels.You will need a simple floor plan with selected sampling points along the path that you're going to walk but before you start walking, you must start NetStumbler and make sure you see live Access Points to make sure NetStumbler is working correctly.