[TriLUG] OFF-TOPIC - microwave radiation

[Joseph Mack NA3T]

On Tue, 9 Sep 2014, David Both wrote:

> In this case the microwave oven leaks enough radiation to jam the wireless 
> signal even though I was about 15 feet from the microwave when this occurred. 
> You should find that scary.

I had a sniffer a couple of years ago. I checked out a few microwave ovens.

o they were all at one end of the g band (I think the lower end).

o they were all broad (as expected for a magnetron), about half of the g band. 
However they were stable, ie the frequency didn't drift at all that I could 
tell, which surprised me.

o the signal strength a couple of feet from the microwave door (about where 
you'd stand while waiting for the water to boil, say 5') was about the same as 
the wifi signals from various waps 10-30' away. I could barely detect the 
microwave at about 10' away.

o the signal from waps is narrow band, while the maggie is broad band noise, so 
the wifi receiver at each end of the link can block out much of the noise. I 
could operate a laptop via wifi standing next to the microwave while it was 
boiling water. There was no change in the wifi connection that I could tell 
(ping time, throughput).

At the moment you can't tell if you have a leaky microwave or a poor wifi 
connection, although the microwave seems most likely.

o Try putting the laptop in the microwave oven as in the page Pete has suggested.

o move the channel your wap is on, to the high end of the g band (or move it 
around). Can you see ping times etc going crazy with the microwave on? Do you 
have good signal strength at the laptop (-50db or better)?

o do other laptops have the same trouble?

> This is a Panasonic Model NN-SD787/797.
>
> Does anyone have an RF/Microwave Signal strength meter I could use to check 
> the leakage?

I have a rat-shack microwave signal strength meter thats a dipole, diode and 
meter. It doesn't pick up anything on a regular microwave oven. This may mean it 
doesn't work, or it only picks up signals from badly leaking ovens. If it 
doesn't pick up a signal, it won't tell you anything. If it picks up a signal, 
all you can tell is that your oven is radiating more than a regular oven. You 
won't know if it's 2db or 40db more.

You're welcome to borrow it.

Microwave ovens are cheap. Or can you borrow one for a weekend?

Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!