[TriLUG] OFF-TOPIC - microwave radiation

[David Burton]

On Tue, Sep 9, 2014 at 9:06 PM, David Both <dboth at millennium-technology.com>
wrote:

>
> Just today (September 09, 2014) I was using my Kindle HDX to browse
> through my FaceBook account when I got the message on screen that I could
> post messages while offline. I checked the signal strength icon and it was
> gone. My wife had just started the microwave to heat the broccoli. As soon
> as the microwave stopped, my wireless signal returned.
>
> 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.
>
> 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 used to have one of these (I should still have it, but I can't seem to
find it right now):
http://www.ebay.com/sch/i.html?_from=R40&_nkw=%28Sperry%2CMicrocheck%2C%22Micro+check%22%29+microwave+%28leakage%2Cdetector%2C%22SMW-2A%22%29&_sacat=0

I doubt it would be very useful to you, though. These meters are sold to
people who worry about the health effects of microwave leakage. The
differences in power between a microwave oven and WiFi are enormous. A
typical microwave oven puts out at least 1000 watts (yours is rated 1250
W). A typical WiFi router might put out 30 mW. That's a 4-1/2 order of
magnitude difference, a/k/a 45 dB
<http://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/23231-powervalues-23231.html>
.

On my Kenmore microwave oven, which is about 35 years old, as I recall, the
meter's needle twitches if I hold the meter along the top edge of the oven
door while microwaving something small, but the needle never goes up to
even the middle of the "green" zone, let alone outside it. If I hold the
meter anywhere else, or if I move it a few inches away from the top edge of
the oven door, the needle doesn't even twitch.

This microwave oven is leaky enough to noticeably interfere with phone
conversations if I stand near it with my (thankfully-soon-to-be-history)
Republic Wireless mobile phone in VoIP/WiFi mode.



On Tue, Sep 9, 2014 at 9:45 PM, Pete Soper <pete at soper.us> wrote:

> It would all depend on how far your device is from the oven. Just a few
> milliwatts of power could swamp the Kindle's receiver... A little bit of
> leakage (maybe -50db) is allowed with an oven.



1000 W  -50 db would be 10 mW, which might well be sufficient to interfere
with a 30 mW WiFi signal, depending on the relative distances between the
various devices.

My first suggestion would be to tweak the position of your router, to try
to get better signal strength:

   - Make sure the antennas are upright.
   - Move the router up to a higher shelf.
   - Move it a few inches further from the wall.
   - Rotate it in 10 or 20° increments.

The "WiFi Analyzer
<https://play.google.com/store/apps/details?id=com.farproc.wifi.analyzer&hl=en>"
app for your android phone is *very* useful for this sort of thing. (Use
it, also, to find the WiFi channels which are least congested in your
neighborhood, and configure your router to use them.)

Once you find the best router position, tape it down, so you don't have to
go through the same process the next time someone dusts that bookshelf.

Hopefully, better signal strength will prevent interference from the
microwave oven from causing you to lose your connection altogether.



On Tue, Sep 9, 2014 at 9:06 PM, David Both <dboth at millennium-technology.com>
 wrote:


> Perhaps this would explain my continuing frequent brain farts. ;-) Where
> is the aluminum foil?db) is allowed with an oven.
>


http://zapatopi.net/afdb/   * :-) *