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Remote monitoring of interference?

 
 
dgeesaman@gmail.com
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      11-24-2007, 09:17 PM
I manage the handful of computers for my wife's office. Trouble is,
it seems they're having major connectivity problems during business
hours (when I'm at my regular job).

I'm looking for an affordable tool that might help log or remotely
track wireless interference issues. WIn XP platform is ideal.
Suggestions please.

Thanks,

Dave
 
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Peter Pan
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      11-25-2007, 12:18 AM
(E-Mail Removed) wrote:
> I manage the handful of computers for my wife's office. Trouble is,
> it seems they're having major connectivity problems during business
> hours (when I'm at my regular job).
>
> I'm looking for an affordable tool that might help log or remotely
> track wireless interference issues. WIn XP platform is ideal.
> Suggestions please.
>
> Thanks,
>
> Dave


Just out of curiosity, what makes you think it is interference from another
network, instead of literally hundreds of devices that won't show up in the
logs? (example, interference from cordless phones, microwaves, wireless
intercoms, industrial sealing equipment - RF plastic heat sealers are
absolutely the worst, etc)


 
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miso@sushi.com
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      11-25-2007, 04:19 AM
On Nov 24, 2:17 pm, "dgeesa...@gmail.com" <dgeesa...@gmail.com> wrote:
> I manage the handful of computers for my wife's office. Trouble is,
> it seems they're having major connectivity problems during business
> hours (when I'm at my regular job).
>
> I'm looking for an affordable tool that might help log or remotely
> track wireless interference issues. WIn XP platform is ideal.
> Suggestions please.
>
> Thanks,
>
> Dave


Kismet allows remote monitoring, though I haven't used that feature
myself. I don't know how the windows version works, but I bet it is a
waste of time. I found it (linux source) more difficult than the run
of the mill tarball to compile, plus you may need to find code
specific to your wifi hardware. Once it works, the program is very
impressive. There is an amazing amount of wifi out there that never
shows up under netstumbler.
 
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dgeesaman@gmail.com
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      11-25-2007, 11:37 AM
On Nov 24, 8:18 pm, "Peter Pan" <PeterPanNOS...@AkamailNOSPAM.com>
wrote:
> dgeesa...@gmail.com wrote:
> > I manage the handful of computers for my wife's office. Trouble is,
> > it seems they're having major connectivity problems during business
> > hours (when I'm at my regular job).

>
> > I'm looking for an affordable tool that might help log or remotely
> > track wireless interference issues. WIn XP platform is ideal.
> > Suggestions please.

>
> > Thanks,

>
> > Dave

>
> Just out of curiosity, what makes you think it is interference from another
> network, instead of literally hundreds of devices that won't show up in the
> logs? (example, interference from cordless phones, microwaves, wireless
> intercoms, industrial sealing equipment - RF plastic heat sealers are
> absolutely the worst, etc)


I never said what I thought the source could be. But looking at her
office space: it's a pool supply store with rented office suites on
both sides of the pool store. I suspect 2.4GHz cordless phones and
microwaves, to be honest. In any case my goal is simply to determine
whether interference is the problem, and find the channels that
minimize it.
 
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dgeesaman@gmail.com
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      11-25-2007, 11:38 AM
On Nov 25, 12:19 am, m...@sushi.com wrote:
> On Nov 24, 2:17 pm, "dgeesa...@gmail.com" <dgeesa...@gmail.com> wrote:
>
> > I manage the handful of computers for my wife's office. Trouble is,
> > it seems they're having major connectivity problems during business
> > hours (when I'm at my regular job).

>
> > I'm looking for an affordable tool that might help log or remotely
> > track wireless interference issues. WIn XP platform is ideal.
> > Suggestions please.

>
> > Thanks,

>
> > Dave

>
> Kismet allows remote monitoring, though I haven't used that feature
> myself. I don't know how the windows version works, but I bet it is a
> waste of time. I found it (linux source) more difficult than the run
> of the mill tarball to compile, plus you may need to find code
> specific to your wifi hardware. Once it works, the program is very
> impressive. There is an amazing amount of wifi out there that never
> shows up under netstumbler.


Phew, it's been a long time since I've compiled a unix tar. I'd need
a whole other computer to run this and sit there collecting data,
correct?

Dave
 
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Kris
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      11-25-2007, 01:21 PM
(E-Mail Removed) writes:
> I manage the handful of computers for my wife's office. Trouble is,
> it seems they're having major connectivity problems during business
> hours (when I'm at my regular job).
>
> I'm looking for an affordable tool that might help log or remotely
> track wireless interference issues. WIn XP platform is ideal.
> Suggestions please.


If packet loss/delay statistics would be useful and you can forward
pings to an always-on wireless device, set up a f8lure ping graph:
http://fruk.net/index.php?fruk=f8lure

That might identify transient interference issues - i.e. you could see
that there was a lot of loss/delays whenever DECT 'phones were used.

If you can't forward pings, it might still be useful to see whether the
internet-connected device itself is having the issues rather than the
wireless.
 
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NotMe
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      11-25-2007, 04:48 PM

(E-Mail Removed) wrote:
> I manage the handful of computers for my wife's office. Trouble is,
> it seems they're having major connectivity problems during business
> hours (when I'm at my regular job).
>
> I'm looking for an affordable tool that might help log or remotely
> track wireless interference issues. WIn XP platform is ideal.
> Suggestions please.
>
> Thanks,
>
> Dave


Found this. No personal experiance may help may not.
http://www.metageek.net/docs/sample-recordings



 
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Jeff Liebermann
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      11-25-2007, 05:15 PM
"(E-Mail Removed)" <(E-Mail Removed)> hath wroth:

>Phew, it's been a long time since I've compiled a unix tar. I'd need
>a whole other computer to run this and sit there collecting data,
>correct?
>Dave


Nope. What you need is a "LiveCD". It boots Linux and runs Kismet.
My favorite is:
<http://www.remote-exploit.org/backtrack.html>
Be sure that the wireless device in the monitor PC is supports. You
can do remote control of sorts with VNC.

However, I think you're wasting your time trying to setup a remote
monitoring station. Kismet will show much more than the typical
Windoze wireless sniffer (Netstumbler) because it will show access
points that hide their SSID and client radios. That's fine if you
expect interference from wi-fi networks, but useless for non-802.11
sources. See list at:
<http://wireless.wikia.com/wiki/Wi-Fi#Interference>

Kismet can be operated remotely as resident inside a WRT54G type
wireless router. No computah required. See "Kismet Drone" or "Kismet
Server":
<http://www.dd-wrt.com/wiki/index.php/Kismet_Server/Drone>
There are several ways to install, configure, and operate a remote
monitor, so please RTFM before attacking. I have several of these
installed (monitoring convention hall usage). However, they are
useless for non-802.11 interference sources.

You might have better luck with a spectrum analyzer. I use several
including the original version of WiSpy:
<http://metageek.net>
I've never tried to operate it by remote control.

The problem here is that the original version is rather deaf and can't
really pickup weak sources of interference. For that, you'll need
either the current model, or a real HP or Tektronix spectrum analyzer.
The cheapest I've found that's usable is a Tektronix 492 which
typically goes for about $1,500.

I'm not sure what to suggest. It's difficult enough to find an
interference source in person. Doing it by remote control might be
impossible. I've never tried it. What I usually end up doing is
borrowing a spectrum analyzer, connecting it to the most directional
antenna I can find (i.e. grid dish), and play transmitter hunt. Even
that's not guaranteed.

My most effective indoor method is just a laptop and ping. I run
continuous ping to the access point and walk around. As I get closer
and closer to the source of interference, the latency and packet loss
both increase. Sitting the laptop next to an operational 2.4GHz
cordless phone usually drops the connection. (Note: interference can
enter at both the client and the access point ends of a wireless
link).

Other methods are to simply monitor the interference and look for a
pattern. I had one problem that would only appear erratically at
around lunch time. At lunchtime, the entire building wireless network
would completely die. After lunch, it would recover. After 3 months
of head scratching, someone else traced it to the worlds most leaky
(and filthy) microwave oven on the noontime lunch truck.

Good luck.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
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miso@sushi.com
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Posts: n/a

 
      11-25-2007, 08:37 PM
On Nov 25, 10:15 am, Jeff Liebermann <je...@cruzio.com> wrote:
> "dgeesa...@gmail.com" <dgeesa...@gmail.com> hath wroth:
>
> >Phew, it's been a long time since I've compiled a unix tar. I'd need
> >a whole other computer to run this and sit there collecting data,
> >correct?
> >Dave

>
> Nope. What you need is a "LiveCD". It boots Linux and runs Kismet.
> My favorite is:
> <http://www.remote-exploit.org/backtrack.html>
> Be sure that the wireless device in the monitor PC is supports. You
> can do remote control of sorts with VNC.
>
> However, I think you're wasting your time trying to setup a remote
> monitoring station. Kismet will show much more than the typical
> Windoze wireless sniffer (Netstumbler) because it will show access
> points that hide their SSID and client radios. That's fine if you
> expect interference from wi-fi networks, but useless for non-802.11
> sources. See list at:
> <http://wireless.wikia.com/wiki/Wi-Fi#Interference>
>
> Kismet can be operated remotely as resident inside a WRT54G type
> wireless router. No computah required. See "Kismet Drone" or "Kismet
> Server":
> <http://www.dd-wrt.com/wiki/index.php/Kismet_Server/Drone>
> There are several ways to install, configure, and operate a remote
> monitor, so please RTFM before attacking. I have several of these
> installed (monitoring convention hall usage). However, they are
> useless for non-802.11 interference sources.
>
> You might have better luck with a spectrum analyzer. I use several
> including the original version of WiSpy:
> <http://metageek.net>
> I've never tried to operate it by remote control.
>
> The problem here is that the original version is rather deaf and can't
> really pickup weak sources of interference. For that, you'll need
> either the current model, or a real HP or Tektronix spectrum analyzer.
> The cheapest I've found that's usable is a Tektronix 492 which
> typically goes for about $1,500.
>
> I'm not sure what to suggest. It's difficult enough to find an
> interference source in person. Doing it by remote control might be
> impossible. I've never tried it. What I usually end up doing is
> borrowing a spectrum analyzer, connecting it to the most directional
> antenna I can find (i.e. grid dish), and play transmitter hunt. Even
> that's not guaranteed.
>
> My most effective indoor method is just a laptop and ping. I run
> continuous ping to the access point and walk around. As I get closer
> and closer to the source of interference, the latency and packet loss
> both increase. Sitting the laptop next to an operational 2.4GHz
> cordless phone usually drops the connection. (Note: interference can
> enter at both the client and the access point ends of a wireless
> link).
>
> Other methods are to simply monitor the interference and look for a
> pattern. I had one problem that would only appear erratically at
> around lunch time. At lunchtime, the entire building wireless network
> would completely die. After lunch, it would recover. After 3 months
> of head scratching, someone else traced it to the worlds most leaky
> (and filthy) microwave oven on the noontime lunch truck.
>
> Good luck.
>
> --
> Jeff Liebermann je...@cruzio.com
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558


Would a zap checker plus filter work for finding the interference
source? I've seen wifi cavity filters for $100 plus change.
http://www.zapchecker.com/
I have the original zapchecker that was being sold as the product line
was being developed. There are mods to add a SMA to the box. Of
course, this is not a remote solution, but more of a curiosity for me.
 
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Jeff Liebermann
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      11-26-2007, 04:28 AM
(E-Mail Removed) hath wroth:

>Would a zap checker plus filter work for finding the interference
>source?


They have several models. One of them claims at:
<http://www.zapchecker.com>
"Standard 2.4 GHz wireless telephones and microwave ovens make
excellent signal sources. Using an operating sealed microwave
oven, it is common to detect the oven’s 2.4 GHz signal using the
Zap Checker products at greater than 10 meters distance. The Zap
Checker Model 300 and ABC 126 with directional Yagi antennas can
detect wireless 2.4 GHz telephones (10 mw of power) at distances
greater than 60 meters."

I played with what I think was the original model with the internal
PCB antenna. It would detect my Wi-Fi access point, but only if I was
moving continuous traffic. When the average transmit duty cycle was
low, it didn't do so well. However, the problem I found is that it
was so sensitive, that ANY nearby RF source would indicate on the
meter. We have a nearby VHF water district remote base. When it
transmits, that's all I could see. If I were anywhere near broadcast
AM/FM/TV transmitters, that's all I would probably see. Without
frequency selectivity, such broadband devices are not very useful.

>I've seen wifi cavity filters for $100 plus change.


Yech. Build your own. A PCB with one of the ceramic BPF filters
found all over wi-fi hardware should be sufficient. If you want lower
loss, a simple cavity resonantor is easy enough to build. There
should be something in the various ARRL microwave books. A narrow
band 2.4GHz antenna will also help.

>http://www.zapchecker.com/
>I have the original zapchecker that was being sold as the product line
>was being developed. There are mods to add a SMA to the box. Of
>course, this is not a remote solution, but more of a curiosity for me.


So, try it. Play T-hunt. Have someone hide a beaconing access point
in your house or office. You get to play transmitter hunt and find
it. Extra credit if you have other wireless access points and clients
in the area creating havoc and confusion. I've actually done this
using a keychain wi-fi finder and reflector, with predictably dismal
results. Bottom line is that if you can't distinguish the desired
xmitter, and can't seperate it from the others, you'll have big
problems.



--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 
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