On 6 Jan 2006 10:15:42 -0800,
(E-Mail Removed) wrote:
>I was curious about how many of you have gotten site surveys for your
>wlan. i was also curious as to what the cost was. i am asking as I
>could potentially have lots of new wlan sites and was wondering if it
>would be more cost effective to get the equipment and do them myself.
>I am not sure what a survey entails, so this is just something i was
>thinking about.
I've done a few genuine site surveys for WISP (wireless ISP's).
Basically, I sniff around with a borrowed spectrum analyzer and look
for potential sources of interference. I also use Netstumbler and
Kismet to look for other wireless networks. I also spend some time on
the internet and look for municipal WLAN's, hot spots, and utilities
that use wireless (i.e. power, refinery, railroad, etc). Also, if a
rooftop is available, I look around for antennas that may cause
problems. In one case, a large area was going to be covered so the
sniffing had to be done from multiple locations. I did some checking
with the city/county to make sure that there were no plans for a
municipal wireless network (there were). I also produced Radio-Mobile
propogation estimates for possible access point locations and a fancy
PDF report.
You could probably do all this yourself. If you want, I can list the
equipment and software you'll need. If you search Google for "site
survey kit", there are several bundles available. Some potential
problems are:
1. Interpreting the spectrum analyzer display. Download and view
this PowerPoint slide show:
http://www.wbanc.com/Network_Coordination.ppt (3.4MB)
Note the spectrum analyzer photo on Page 13. Could you recognize the
systems? It's really easy to miss signals. Incidentally, you might
check if your area has some form of coordination:
http://www.wbanc.com
2. Finding a location to do the testing from is tricky. In general,
you want to be where the equipment is going to be placed. In reality,
getting access to rooftops and high places is a pain. You also have
to drag along quite a bit of equipment and antennas. I've had the
local police express an eggagerated interest in what I was doing.
3. Producing a report that was intelligible to the money jugglers was
a major problem. That may sound easy but it's not. If this is for
yourself, of course no report is necessary.
4. Site surveys are actually moving targets. An area that's clear of
RF pollution today, may not be so tomorrow. If you're doing the WISP
thing, then monitoring for other systems should be a continuous
exercise. Unfortunatly, I've never convinced anyone to do so.
Incidentally, I just bought one of these spectrum analyzers.
http://www.metageek.net
Works "good enough" for interference detection. However, I have not
had time to do a proper field test, which is waiting for some SMA
connectors to arrive so I can attach an external antenna.
Don't send me email asking for a price quote. I don't wanna do any
more site surveys and reports. I made enough money to make it worth
the travel, but it's just too much work to do it right.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
(E-Mail Removed)
#
http://802.11junk.com (E-Mail Removed)
#
http://www.LearnByDestroying.com AE6KS
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