adykes@panix.com (Al Dykes) hath wroth:

>What's so hard. Put the AP in a table, put a laptop with netstumbler
>on a table far enough away to get a middle reading and then go back
>and put the plastic box over the AP. Don't move anything. walk back to
>the laptop. look at the graph.

Have you actually tried it? I have. Let's try something simple.
Setup your laptop on the table with Netstumbler and have it probe your
own access point. Never mind the pretty graphs, just look at the
signal strength and SNR numbers. I'll assume you have the typical
rubber ducky antennas on your access point.

Now, take a 6" or so piece of PVC or ABS pipe and slide it over one or
both antennas on the access point. Record the measurements before and
after inserting the pipes. Go away and get some coffee or tea. Record
the before and after measurements again. Go away and watch a TV show.
Record the measurements before and after. Open or close a door or
window. Do it again. If you're really lucky, you'll have a +/- 3dB
spread in values of signal strength, and about twice that for SNR.

>I agree that, in general antenna measurements are a PITA.

Yep, especially indoors where uncontrolled measurements are the norm.

Incidentally, if you have access to a spectrum analyzer that does NOT
have a digital readout, put a spread spectrum signal on the screen
from a controlled source (signal generator or directly connected
access point), and ask your available friends and accomplices to read
the indicated level off the screen. My guess is about +/- 2dB
variation depending on the focus. Incidentally, tall people tend to
produce low readings, while short people produce high readings, both
due to parallax.

So, have you figured out the spectrum analyzer quiz question?

--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558