On Sat, 20 Jun 2009 17:54:04 +0000 (UTC), "Geoffrey S. Mendelson"
wrote:
I have a microwave leakage tester. It is calibrated for 2450 mHz, so it should
be perfect for testing WiFi Network output power. It is calibrated in mw/cm2
(miliwatts per square centimeter). It is also ham related as I am limited to
100mw EIRP on the 2.4gHz ham band.
So I figured that I could use it by measuring the field strength at a specific
distance from the antenna, and then applying a conversion factor.
See if you can get your money back. I had the same idea a few years
ago and purchased a Safeea Inc MD-2000 tester:
http://www.allproducts.com/ee/safeea/md-2000.html
Of course, the first thing I did was rip it apart:
http://802.11junk.com/jeffl/pics/Microwave%20Leakage%20Detector/index.html
The diode D1 (labelled C2) is the detector. The apparently random
circuit board traces nearby is the "antenna".
The sensitivity sucks. I'm only able to get an indication when it's a
few cm from the antenna of my access point. Worse, the indication
varies radically from zilch to tilt (9.9mw/cm^2). There's no stable
indication. At the microwave oven leak test distance of 2 inches, it
barely indicates anything, even when I generate continuous traffic
with my iPod Touch. If there were some way to generate a CW carrier
from the access point, perhaps it might deliver a better and more
stable indication.
The problem is that the duty cycle of Wi-Fi transmissions are not
constant. The MD-2000 microwave leak detector works nicely with the
constant duty cycle of the oven controller, but doesn't do as well
with the widely varying duty cycle of Wi-Fi. Also, the duty cycle of
just the beacon transmissions is very low, resulting in a very low
indication.
I also have several analog oven leak detectors, which produce similar
disgusting results.
Topic Drift: Think your microwave oven is well shielded? Put your
2.4GHz cordless phone handset inside the microwave oven. Close the
door. Hit the "page" button on the phone base and see if the phone
rings. It probably will. So much for shielding.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558