Hi everyone,
I have a small network at home with a wireless xDSL/cable router. I am using a Netgear FR114PAU gateway and a Netgear MA401 wireless NIC in my notebook.
As I sat on my couch last night chatting to 'net friends before NYE festivities, I decided to cook myself a meal in my trusty microwave.
I noticed that as soon as the microwave started cooking, my wireless LAN connection went to the dogs. Link speed fell to close to 0Mbps, XP reported the link quality as very poor.
As soon as the microwave stopped, my link quality was once again excellent and speed back at 11Mbps.
My question is this - is my microwave leaking some sort of radiation it shouldn’t be… and is this dangerous to me?
Cheers,
Dunno what the standards are Down Under, but US microwaves don’t leak dangerous amounts of radiation. And anyway, the danger from microwave radiation isn’t like the danger from nuclear radiation, it’s totally different. (You knew that, right?
http://www.fda.gov/cdrh/consumer/microwave.html
All microwave ovens made after October 1971 are covered by a radiation safety standard enforced by the FDA. The standard limits the amount of microwaves that can leak from an oven throughout its lifetime. The limit is 5 milliwatts of microwave radiation per square centimeter at approximately 2 inches from the oven surface. This is far below the level known to harm people. Furthermore, as you move away from an oven, the level of any leaking microwave radiation that might be reaching you decreases dramatically. For example, someone standing 20 inches from an oven would receive approximately one one-hundredth of the amount of microwaves received at 2 inches.
The standard also requires all ovens to have two independent interlock systems that stop the production of microwaves the moment the latch is released or the door opened. In addition, a monitoring system stops oven operation in case one or both of the interlock systems fail. The noise that many ovens continue to make after the door is open is usually the fan. The noise does not mean that microwaves are being produced. There is no residual radiation remaining after microwave production has stopped. In this regard a microwave oven is much like an electric light that stops glowing when it is turned off.
All ovens made since October 1971 must have a label stating that they meet the safety standard. In addition, FDA requires that all ovens made after October 1975 have a label explaining precautions for use. This requirement may be dropped if the manufacturer has proven that the oven will not exceed the allowable leakage limit even if used under the conditions cautioned against on the label.
To make sure the standard is met, FDA tests microwave ovens in commercial establishments, dealer and distributor premises, manufacturing plants, and its own laboratories. FDA also evaluates manufacturers’ radiation testing and quality control programs. When FDA finds a radiation safety problem in a certain model or make of oven, it requires the manufacturer to correct all defective ovens at no cost to the consumer.
Although FDA believes the standard assures that microwave ovens do not present any radiation hazard, the Agency continues to reassess its adequacy as new information becomes available.
However, apparently microwaves can emit enough radiation to interfere with wireless networks.
http://ntrg.cs.tcd.ie/undergrad/4ba2.02/wireless/reg2.html
There seems to be a common perception (possibly formulated by supporters of 3G networks) that an interference source of wireless LAN’s is the ubiquitous microwave oven, which operates in the 2.4 Ghz band. However research has shown that a microwave oven emits a single CW tone on a 50% duty cycle, 8.3 mSec on and 8.3 mSec off. IEEE802.11 has an optional feature that allows it to keep clear of the 8.3 mSec ON time, by using a software “primitive” called CCA (Clear Channel Assessment). So to ensure no interference is present, transmission is done when CCA is False.
However, it seems that microwave oven interference potential is over-rated. The flux density of the interference is not very powerful in most cases. Simply moving the wireless LAN adaptor a reasonable distance away from the microwave will allow a wireless connection that has imperceptible performance degradation.
http://www.80211-planet.com/columns/print.php/947661
For 2.4 GHz wireless LANs, there are several sources of interfering signals, including microwave ovens, wireless phones, Bluetooth enabled devices, and other wireless LANs. The most damaging of these are 2.4 GHz wireless phones that people are starting to use in homes and some companies. If one of these phones is in use within the same room as an 802.11b wireless LAN, then expect poor wireless LAN performance.
Microwave ovens operating within 10 feet or so of an access point or radio-equipped user will generally just cause 802.11b performance to drop. Bluetooth enabled devices, such as laptops and PDAs, will also cause performance degradations if operating in close proximately to 802.11 stations, especially if the 802.11 station is relatively far (i.e., low signal levels) from the station that it’s communicating with. The 802.11 and 802.15 standards groups, however, are working on a standard that will enable the coexistence of Bluetooth and 802.11 devices. Other wireless LANs, such as one that your neighbor may be operating, can cause interference unless you coordinate the selection of 802.11b channels.
So you’re okay, but your network isn’t.
Thanks Ducky, you’re a fountain of information
Max
ftg
January 2, 2003, 6:20pm
4
One possibility to consider is that “RF noise” (well, very high freq. RF noise) is going out of the microwave via the power cord and thence “broadcast” throughout the house, as well as possibly entering the base station via it’s power cord. An RF choke (split toroid magnets) can be added on to power cords easily enough. Radio Shack sells them. But they may not fit the microwave power cord and putting them on the base station cord would be far less desirable. But still something cheap and easy to try.
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