The explosive growth of wireless applications has contributed to an increased level of interference with your wireless network known as co-channel and adjacent channel interference. In addition a close physical proximity in the same given location of large number of users using similar service (i.e. Wi-Fi, Bluetooth) will cause a significant raise of the environmental RF noise floor and hence causing a degrading performance for all users in such location (i.e. dense apartment buildings, stadiums, etc.).
There are many types of devices operating in the unlicensed ISM (industrial, scientific and medical) bands.
These devices include microwave ovens, cordless phones, Bluetooth devices, wireless video cameras, outdoor microwave links,
wireless controllers of various type, Zigbee, fluorescent lights, WiMax, electronic water/power meters, etc. Even bad electrical
connections or appliances can cause unintended broad RF spectrum emissions (interference) that violates emission rules established
by the governing body for a given country.
In most cases, RF interference is often intermittent in nature and may occur only at certain times of day or on certain days of the week.
Unless an initial RF sweep is done for an extended time, it is very easy to miss intermittent sources of interference. No amount of periodic sweeping
can truly guarantee that you have an interference-free environment at all times. However it may help to identify someone that it does not comply with RF radiation
regulations and such devices can be forced to shut down.