I'm wondering if these numbers mean anything to you guys in
the know about wireless stuff.
With a standard antenna on my WAP54G I see these numbers on
the screen of a laptop connected to the AP using a WPC54G PC
Card: noise -68dBm, signal -78dBm, link quality (I think
it's called) 27%.
Then I put a small corner reflector on one of the WAP54G
antennas and it bumped up the lightbars and I got
noise -58dBm, signal -68dBm, and quality 47%.
I was surprised at several things. I was a bit surprised
that the S/N was so low to begin but I can accept that. But
why the heck wouldn't the S/N improve with a stronger signal
from the AP? These numbers show both S and N going up 10dB.
Finally, especially at low S/N I would have expected any
measure of data quality would do more than double if S/N
went up 10dB.
Clearly I'm not up on this wireless system. I have looked
around at some technical places but have never seen this
subject discussed. Could you guys in the know point me where
I can make sense of all this? Thanks.
>I'm wondering if these numbers mean anything to you guys in
>the know about wireless stuff.
Hang on a minute. I gotta put on my wizards hat.
>With a standard antenna on my WAP54G I see these numbers on
>the screen of a laptop connected to the AP using a WPC54G PC
>Card: noise -68dBm, signal -78dBm, link quality (I think
>it's called) 27%.
I think you have the signal and noise backwards. The noise cannot be
more than the signal or you wouldn't hear anything. Assuming your
numbers are backwards, that yields:
The link quality number varies with the chipset used. There are
different algorithms all of which are based on the percentage of the
S/N ratio required to get a perfect BER (bit error rate) at whatever
speed it's running at. I have the numbers buried here somewhere if
you really want them. More commonly, the link quality is a measure of
the actual BER. The more receive errors, the worse the link quality.
That causes some rather bizarre results in the presense of
interference. See below.
>Then I put a small corner reflector on one of the WAP54G
>antennas and it bumped up the lightbars and I got
>noise -58dBm, signal -68dBm, and quality 47%.
Note that BOTH the signal and noise levels were increased by the
corner reflector. That's what happens when you have a source of
interference in the line of sight. The chipset treat everything that
is not 802.11 or the desired access point as "noise".
The reason the link quality went from 27% to 47% is that the strong
signal made it easier to demodulate the data. In theory, the link
quality should exactly follow the S/N ratio, but different types of
intereference cause different types of data reception errors.
>I was surprised at several things. I was a bit surprised
>that the S/N was so low to begin but I can accept that. But
>why the heck wouldn't the S/N improve with a stronger signal
>from the AP? These numbers show both S and N going up 10dB.
Please check your numbers and try again?
>Finally, especially at low S/N I would have expected any
>measure of data quality would do more than double if S/N
>went up 10dB.
Nope. My guess(tm) is that your WPC54G uses the data error rate to
determine the link quality. You could simply add a noise or
interference source and the signal levels will not change. The noise
level should change with the added interference. However, if you are
at some threshold (as you probably are with such a lousy SNR), then
the effects will be proportionally larger due to threhold effects.
>Clearly I'm not up on this wireless system. I have looked
>around at some technical places but have never seen this
>subject discussed. Could you guys in the know point me where
>I can make sense of all this? Thanks.
Not exactly. It's in the data sheets and application notes for the
chipset, which often require an NDA or sacrifice of the first born to
obtain. 2nd best are articles on the topic. Try searching:
<http://www.commsdesign.com>
<http://www.atheros.com/pt/papers.html>
There are others but these are a good start. If I find anything
useful, I'll post.
I sorta blundered across these articles that looks useful:
<http://www.cisco.com/en/US/products/hw/wireless/ps4555/products_installation_and_configuration_guide_chap ter09186a0080380e69.html>
<http://lists.shmoo.com/pipermail/hostap/2006-December/014685.html>
Believe me, the numbers I gave were what is clearly seen on
the screen, checked numerous times. I am really confused as
to why the noise level would go up with the signal. I'm
wondering if the guy at Linksys that formatted the output
was thinking more about lunch than what he was doing.
Thanks for the links, I'll check them and see what I can
learn about this business. Rob
Jeff Liebermann wrote:
> rob <robIV@piovere.com> hath wroth:
>
>
>>I'm wondering if these numbers mean anything to you guys in
>>the know about wireless stuff.
>
>
> Hang on a minute. I gotta put on my wizards hat.
>
>
>>With a standard antenna on my WAP54G I see these numbers on
>>the screen of a laptop connected to the AP using a WPC54G PC
>>Card: noise -68dBm, signal -78dBm, link quality (I think
>>it's called) 27%.
>
>
> I think you have the signal and noise backwards. The noise cannot be
> more than the signal or you wouldn't hear anything. Assuming your
> numbers are backwards, that yields:
>
> signal = -68dBm
> noise = -78dBm
> S/N = 10dB (which sucks)
>
> The link quality number varies with the chipset used. There are
> different algorithms all of which are based on the percentage of the
> S/N ratio required to get a perfect BER (bit error rate) at whatever
> speed it's running at. I have the numbers buried here somewhere if
> you really want them. More commonly, the link quality is a measure of
> the actual BER. The more receive errors, the worse the link quality.
> That causes some rather bizarre results in the presense of
> interference. See below.
>
>
>>Then I put a small corner reflector on one of the WAP54G
>>antennas and it bumped up the lightbars and I got
>>noise -58dBm, signal -68dBm, and quality 47%.
>
>
> Again backwards. I'll assume:
>
> signal = -58dBm
> noise = -68dBm
> S/N = 10dB (which sucks)
>
> Note that BOTH the signal and noise levels were increased by the
> corner reflector. That's what happens when you have a source of
> interference in the line of sight. The chipset treat everything that
> is not 802.11 or the desired access point as "noise".
>
> The reason the link quality went from 27% to 47% is that the strong
> signal made it easier to demodulate the data. In theory, the link
> quality should exactly follow the S/N ratio, but different types of
> intereference cause different types of data reception errors.
>
>
>>I was surprised at several things. I was a bit surprised
>>that the S/N was so low to begin but I can accept that. But
>>why the heck wouldn't the S/N improve with a stronger signal
>
>>from the AP? These numbers show both S and N going up 10dB.
>
> Please check your numbers and try again?
>
>
>>Finally, especially at low S/N I would have expected any
>>measure of data quality would do more than double if S/N
>>went up 10dB.
>
>
> Nope. My guess(tm) is that your WPC54G uses the data error rate to
> determine the link quality. You could simply add a noise or
> interference source and the signal levels will not change. The noise
> level should change with the added interference. However, if you are
> at some threshold (as you probably are with such a lousy SNR), then
> the effects will be proportionally larger due to threhold effects.
>
>
>>Clearly I'm not up on this wireless system. I have looked
>>around at some technical places but have never seen this
>>subject discussed. Could you guys in the know point me where
>>I can make sense of all this? Thanks.
>
>
> Not exactly. It's in the data sheets and application notes for the
> chipset, which often require an NDA or sacrifice of the first born to
> obtain. 2nd best are articles on the topic. Try searching:
> <http://www.commsdesign.com>
> <http://www.atheros.com/pt/papers.html>
> There are others but these are a good start. If I find anything
> useful, I'll post.
>
> I sorta blundered across these articles that looks useful:
> <http://www.cisco.com/en/US/products/hw/wireless/ps4555/products_installation_and_configuration_guide_chap ter09186a0080380e69.html>
> <http://lists.shmoo.com/pipermail/hostap/2006-December/014685.html>
>
>
>Believe me, the numbers I gave were what is clearly seen on
>the screen, checked numerous times. I am really confused as
>to why the noise level would go up with the signal. I'm
>wondering if the guy at Linksys that formatted the output
>was thinking more about lunch than what he was doing.
Try the same measurements with:
1. Using the Linksys client instead of Wireless Zero Config
2. Netstumbler
3. A different laptop
It doesn't make any sense to have more noise than signal. Something
is weird on your WPC54G client. If you change your setup from Windoze
Wireless Zero Config, and switch to the Linksys supplied client, you
can get S/N info from the "Link Information" tab, and not get
entangled in the % link quality conversion. Hopefully, you'll see
better numbers. Also, check that you have the latest WPC54G drivers
installed.
>
>Thanks for the links, I'll check them and see what I can
>learn about this business. Rob
>
>Jeff Liebermann wrote:
>
>> rob <robIV@piovere.com> hath wroth:
>>
>>
>>>I'm wondering if these numbers mean anything to you guys in
>>>the know about wireless stuff.
>>
>>
>> Hang on a minute. I gotta put on my wizards hat.
>>
>>
>>>With a standard antenna on my WAP54G I see these numbers on
>>>the screen of a laptop connected to the AP using a WPC54G PC
>>>Card: noise -68dBm, signal -78dBm, link quality (I think
>>>it's called) 27%.
>>
>>
>> I think you have the signal and noise backwards. The noise cannot be
>> more than the signal or you wouldn't hear anything. Assuming your
>> numbers are backwards, that yields:
>>
>> signal = -68dBm
>> noise = -78dBm
>> S/N = 10dB (which sucks)
>>
>> The link quality number varies with the chipset used. There are
>> different algorithms all of which are based on the percentage of the
>> S/N ratio required to get a perfect BER (bit error rate) at whatever
>> speed it's running at. I have the numbers buried here somewhere if
>> you really want them. More commonly, the link quality is a measure of
>> the actual BER. The more receive errors, the worse the link quality.
>> That causes some rather bizarre results in the presense of
>> interference. See below.
>>
>>
>>>Then I put a small corner reflector on one of the WAP54G
>>>antennas and it bumped up the lightbars and I got
>>>noise -58dBm, signal -68dBm, and quality 47%.
>>
>>
>> Again backwards. I'll assume:
>>
>> signal = -58dBm
>> noise = -68dBm
>> S/N = 10dB (which sucks)
>>
>> Note that BOTH the signal and noise levels were increased by the
>> corner reflector. That's what happens when you have a source of
>> interference in the line of sight. The chipset treat everything that
>> is not 802.11 or the desired access point as "noise".
>>
>> The reason the link quality went from 27% to 47% is that the strong
>> signal made it easier to demodulate the data. In theory, the link
>> quality should exactly follow the S/N ratio, but different types of
>> intereference cause different types of data reception errors.
>>
>>
>>>I was surprised at several things. I was a bit surprised
>>>that the S/N was so low to begin but I can accept that. But
>>>why the heck wouldn't the S/N improve with a stronger signal
>>
>>>from the AP? These numbers show both S and N going up 10dB.
>>
>> Please check your numbers and try again?
>>
>>
>>>Finally, especially at low S/N I would have expected any
>>>measure of data quality would do more than double if S/N
>>>went up 10dB.
>>
>>
>> Nope. My guess(tm) is that your WPC54G uses the data error rate to
>> determine the link quality. You could simply add a noise or
>> interference source and the signal levels will not change. The noise
>> level should change with the added interference. However, if you are
>> at some threshold (as you probably are with such a lousy SNR), then
>> the effects will be proportionally larger due to threhold effects.
>>
>>
>>>Clearly I'm not up on this wireless system. I have looked
>>>around at some technical places but have never seen this
>>>subject discussed. Could you guys in the know point me where
>>>I can make sense of all this? Thanks.
>>
>>
>> Not exactly. It's in the data sheets and application notes for the
>> chipset, which often require an NDA or sacrifice of the first born to
>> obtain. 2nd best are articles on the topic. Try searching:
>> <http://www.commsdesign.com>
>> <http://www.atheros.com/pt/papers.html>
>> There are others but these are a good start. If I find anything
>> useful, I'll post.
>>
>> I sorta blundered across these articles that looks useful:
>> <http://www.cisco.com/en/US/products/hw/wireless/ps4555/products_installation_and_configuration_guide_chap ter09186a0080380e69.html>
>> <http://lists.shmoo.com/pipermail/hostap/2006-December/014685.html>
>>
>>
--
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
The only setup I know of that I used to configure my PC Card
on the laptop was what came with the card. Don't know what
Win Zero Config is but I'll try to find out. I have read
about netstumbler but it seemed like a lot of stuff to wade
into and since I finally got the laptop connecting, I didn't
bother with it. I'll look it up again and see what it is.
Don't have another laptop.
I have not yet seen any numbers for what S/N these wireless
links operate at (and I have been looking thru the links you
gave out). But the telemetry links I have played with run at
S/N below one to optimize bit rate/power which our friend
Shannon pointed out. As I understand it, thruput is linear
with BW but logrithmic in S/N.
Thanks
Jeff Liebermann wrote:
Try the same measurements with:
1. Using the Linksys client instead of Wireless Zero Config
2. Netstumbler
3. A different laptop
<snip>
On Mon, 05 Mar 2007 12:35:42 -0600, rob <robIV@piovere.com> wrote in
<45ec630b$0$28127$4c368faf@roadrunner.com>:
>The only setup I know of that I used to configure my PC Card
>on the laptop was what came with the card. Don't know what
>Win Zero Config is but I'll try to find out.
That's using Windows XP to manage wireless instead of the card vendor's
utility. Check for an option to do that.
>I have read
>about netstumbler but it seemed like a lot of stuff to wade
>into and since I finally got the laptop connecting, I didn't
>bother with it. I'll look it up again and see what it is.
>Don't have another laptop.
It's actually pretty easy to use -- install and give it a try.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
John, I got netstumbler and installed it on the laptop which
has a WPC54G talking nicely to a WAP54G. But after about 30
minutes of trying everything I could see, it continued to
say "no wireless adapter found" (or close to that). I found
at least one place that indicated that the Linksys PC Card
adaptor is supported but I never found "WPC54G" explicitly
given. So, if I could get past this one problem, perhaps I
would find it easy to use.
I never saw it mentioned but I presumed that the Laptop with
the "client" adapter (I think it is called) is the place to
use netstumbler. Just in case I put it on the machine wired
to the WAP54G and got the same response - no adaptor found.
I'll play with it some more and maybe I'll "stumble" into
how to make it work. Thanks.
John Navas wrote:
>>about netstumbler but it seemed like a lot of stuff to wade
>>into and since I finally got the laptop connecting, I didn't
>>bother with it. I'll look it up again and see what it is.
>>Don't have another laptop.
>
>
> It's actually pretty easy to use -- install and give it a try.
>
Check the available adapters under Device in Network Stumbler -- I have
to specify the NDIS driver to get it to work with my Atheros-based
wireless adapter.
On Mon, 05 Mar 2007 19:25:34 -0600, rob <robIV@piovere.com> wrote in
<45ecc322$0$8914$4c368faf@roadrunner.com>:
>John, I got netstumbler and installed it on the laptop which
>has a WPC54G talking nicely to a WAP54G. But after about 30
>minutes of trying everything I could see, it continued to
>say "no wireless adapter found" (or close to that). I found
>at least one place that indicated that the Linksys PC Card
>adaptor is supported but I never found "WPC54G" explicitly
>given. So, if I could get past this one problem, perhaps I
>would find it easy to use.
>
>I never saw it mentioned but I presumed that the Laptop with
>the "client" adapter (I think it is called) is the place to
>use netstumbler. Just in case I put it on the machine wired
>to the WAP54G and got the same response - no adaptor found.
>
>I'll play with it some more and maybe I'll "stumble" into
>how to make it work. Thanks.
>
>John Navas wrote:
>
>>>about netstumbler but it seemed like a lot of stuff to wade
>>>into and since I finally got the laptop connecting, I didn't
>>>bother with it. I'll look it up again and see what it is.
>>>Don't have another laptop.
>>
>> It's actually pretty easy to use -- install and give it a try.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
>The only setup I know of that I used to configure my PC Card
>on the laptop was what came with the card. Don't know what
>Win Zero Config is but I'll try to find out.
Find the check box under the properties for the wireless device with
something like "Let Windoze Manage the Connection". With it checked,
you get Windoze Wireless Zero Config. Unchecked and it goes to the
vendor supplied client. If you uncheck the box, you may need to
reboot as the Windoze Wireless Zero Config service is not
automatically killed until the next reboot. If you're in a hurry,
just go to:
Control Panel -> Admin Tools -> Services
and find the line for Windoze Wireless Zero Config. Hit "Stop".
>I have read
>about netstumbler but it seemed like a lot of stuff to wade
>into and since I finally got the laptop connecting, I didn't
>bother with it. I'll look it up again and see what it is.
<http://www.netstumbler.com/downloads/>
Install and operation is quite simple. If your wireless uses an NDIS
5.1 driver (most do), then it should work.
>Don't have another laptop.
Borrow one. I the opposite problem.... too many laptops. It's handy
for testing, but keeping them up to date is a time burner. You're
probably better off with just one laptop.
>I have not yet seen any numbers for what S/N these wireless
>links operate at (and I have been looking thru the links you
>gave out).
Ask and ye shall receive. The minimum Eb/No is the minimum signal to
noise ratio that 802.11 will operate at a given speed. Note that it
varies radically with speed.
What happens is that the your router does its best to maintain a
constant BER (bit error rate). If it climbs, the router slows down
the wireless connection speed until the BER improves. Actually, it
uses PER (packet error rate) which is easier to calculate but the
effect is the same. What the user sees is a constant S/N ratio which
is directly proportional to the error rate.
If you want to see the SNR change, dive into the routers wireless
setup and change the connection speed from "auto" to 54Mbits/sec. That
will yield a radically varying SNR with signal strength.
>But the telemetry links I have played with run at
>S/N below one to optimize bit rate/power which our friend
>Shannon pointed out. As I understand it, thruput is linear
>with BW but logrithmic in S/N.
Yep, that's the way it works for everything else remaining constant.
In this case, the varying connection rate and modulation method, and
the routers attempt to maintain a constant BER/PER, is what's causing
an almost constant SNR. Even so, the noise level should NOT be higher
than the signal level, so something odd is happening.
Jeff, thanks for all the info. I'll definitely try again
with the netstumbler and look for a way to make it use NDIS.
On those dB figures, I'm using Linksys WAP54G/WPC54G, which
type of modulation do you figure it's using?
Jeff Liebermann wrote:
> rob <robIV@piovere.com> hath wroth:
>
>
>>The only setup I know of that I used to configure my PC Card
>>on the laptop was what came with the card. Don't know what
>>Win Zero Config is but I'll try to find out.
>
>
> Find the check box under the properties for the wireless device with
> something like "Let Windoze Manage the Connection". With it checked,
> you get Windoze Wireless Zero Config. Unchecked and it goes to the
> vendor supplied client. If you uncheck the box, you may need to
> reboot as the Windoze Wireless Zero Config service is not
> automatically killed until the next reboot. If you're in a hurry,
> just go to:
> Control Panel -> Admin Tools -> Services
> and find the line for Windoze Wireless Zero Config. Hit "Stop".
>
>
>>I have read
>>about netstumbler but it seemed like a lot of stuff to wade
>>into and since I finally got the laptop connecting, I didn't
>>bother with it. I'll look it up again and see what it is.
>
>
> <http://www.netstumbler.com/downloads/>
> Install and operation is quite simple. If your wireless uses an NDIS
> 5.1 driver (most do), then it should work.
>
>
>>Don't have another laptop.
>
>
> Borrow one. I the opposite problem.... too many laptops. It's handy
> for testing, but keeping them up to date is a time burner. You're
> probably better off with just one laptop.
>
>
>>I have not yet seen any numbers for what S/N these wireless
>>links operate at (and I have been looking thru the links you
>>gave out).
>
>
> Ask and ye shall receive. The minimum Eb/No is the minimum signal to
> noise ratio that 802.11 will operate at a given speed. Note that it
> varies radically with speed.
>
> Speed Min Modulation Typical Noise
> Eb/No Sensit Floor
> mb/sec dB dBm dBm
> 11 7.0 CCK -82 -89
> 5.5 6.0 CCK -85 -91
> 2 1.6 DQPSK -86 -87.6
> 1 -3.0 DBPSK -89 -86
> 54 24.6 64QAM/OFDM -71 -95.6
> 48 24.1 64QAM/OFDM -71 -95
> 36 18.8 16QAM/OFDM -78 -96.8
> 24 17.0 16QAM/OFDM -79 -96
> 18 10.8 QPSK/OFDM -82 -92.8
> 12 9.0 QPSK/OFDM -84 -93
> 9 7.8 BPSK/OFDM -87 -94.8
> 6 6.0 BPSK/OFDM -88 -94
>
> What happens is that the your router does its best to maintain a
> constant BER (bit error rate). If it climbs, the router slows down
> the wireless connection speed until the BER improves. Actually, it
> uses PER (packet error rate) which is easier to calculate but the
> effect is the same. What the user sees is a constant S/N ratio which
> is directly proportional to the error rate.
>
> If you want to see the SNR change, dive into the routers wireless
> setup and change the connection speed from "auto" to 54Mbits/sec. That
> will yield a radically varying SNR with signal strength.
>
>
>>But the telemetry links I have played with run at
>>S/N below one to optimize bit rate/power which our friend
>>Shannon pointed out. As I understand it, thruput is linear
>>with BW but logrithmic in S/N.
>
>
> Yep, that's the way it works for everything else remaining constant.
> In this case, the varying connection rate and modulation method, and
> the routers attempt to maintain a constant BER/PER, is what's causing
> an almost constant SNR. Even so, the noise level should NOT be higher
> than the signal level, so something odd is happening.
>
>
Jeff, I just tried netstumbler again. In the device menu the
only option is "use any suitable device". One line above
that is an Intel something but it is greyed out. Also I did
find a site that said my specific Linksys WPC54G card is
supported. So, while that very card is nicely linked to my
AP, netstubler just won't do anything at all. The only
version available that I can find is 0.4. Doesn't sound like
it's been around too long.
I looked around and found a Kismet but it must be for Macs.
I also found and tried a UfaSoft product freebie. Damn, it
finds the IP's of all my wireless components but there's no
way I can get it to sniff the area. And as expected for a
freebie, there's no documentation that really tells
anything. I'll keep looking around; this sniffing sounds
like a neat feature and maybe eventually I'll get it.
On Tue, 06 Mar 2007 13:05:56 -0600, rob <robIV@piovere.com> wrote:
>Jeff, thanks for all the info. I'll definitely try again
>with the netstumbler and look for a way to make it use NDIS.
I don't think you have to search for NDIS. Just install an run
Netstumbler 0.40. If it works, you have an NDIS driver. Just about
everything for XP and w2K use NDIS drivers.
>On those dB figures, I'm using Linksys WAP54G/WPC54G, which
>type of modulation do you figure it's using?
The modulation method varies with the connection speed. Get the
operating wireless speed from your WPC54G connection manager, and just
look up the corresponding details in the chart supplied.
On Tue, 06 Mar 2007 17:26:42 -0600, rob <robIV@piovere.com> wrote:
>Jeff, I just tried netstumbler again. In the device menu the
>only option is "use any suitable device". One line above
>that is an Intel something but it is greyed out.
That could be your ethernet. Your WPC54G should be recognized, which
apparently it's not. No clue why it's failing.
>Also I did
>find a site that said my specific Linksys WPC54G card is
>supported. So, while that very card is nicely linked to my
>AP, netstubler just won't do anything at all. The only
>version available that I can find is 0.4. Doesn't sound like
>it's been around too long.
That's the current version of Netstumbler. Why update something that
works just fine?
>I looked around and found a Kismet but it must be for Macs.
There is a MacIntosh version, but Kismet is primarly written for
Linux.
>I also found and tried a UfaSoft product freebie. Damn, it
>finds the IP's of all my wireless components but there's no
>way I can get it to sniff the area. And as expected for a
>freebie, there's no documentation that really tells
>anything. I'll keep looking around; this sniffing sounds
>like a neat feature and maybe eventually I'll get it.
Well, if you're shopping for a connection manager, try:
<http://wifihopper.com>
Works fine for me, with one gotcha. It installs a WiFiHopper service
which seems to interfere with other Wi-Fi sniffers. Try it, but be
prepared to disable the service if you try others:
Control Panel -> Admin Tools -> Services
I tried it and amazingly it does see my AP. But it's a
freebie and not much else works.
The signal level it shows stays at -64dBm(/Mhz I presume)
even though I cover my antenna with my hand. My Linksys
measurement shows signal dropping but hopper level never
changes. Clearly it isn't finding the actual level.
It doesn't find my neighbor's AP, no filters on. Linksys
monitor does find it. I guess my Linksys monitor is a form
of sniffer but all it does is list the ssid and strength, no
other info is given. But it gives more than hopper.
Apparently the hopper didn't interfere with the Linksys
monitor, it's still working the same.
Also the HELP menu item doesn't work so I can't really study
how to use the thing. Maybe if I pay for it they will give
me the help files.
So I still don't have anything that does much sniffing but
I'll keep looking. Thanks for your input. Rob
> Well, if you're shopping for a connection manager, try:
> <http://wifihopper.com>
> Works fine for me, with one gotcha. It installs a WiFiHopper service
> which seems to interfere with other Wi-Fi sniffers. Try it, but be
> prepared to disable the service if you try others:
> Control Panel -> Admin Tools -> Services
>
>I tried it and amazingly it does see my AP. But it's a
>freebie and not much else works.
It? Oh, WiFiHopper. It's not exactly free. The sniffer part of the
puzzle is essentially free. The connection manager part times out
after 15 or 30 days. The connection manager part is actually quite
handy (for me) as it will allow me to connect by MAC address instead
of SSID. That's useful when I have to deal with a network of access
points, all with the same SSID.
>The signal level it shows stays at -64dBm(/Mhz I presume)
>even though I cover my antenna with my hand. My Linksys
>measurement shows signal dropping but hopper level never
>changes. Clearly it isn't finding the actual level.
Use the graph, not the table to get your numbers. The table does not
update in real time.
>It doesn't find my neighbor's AP, no filters on.
Are they broadcasting their SSID?
>Linksys
>monitor does find it.
The Linksys monitor is nifty. It shows access points that don't
broadcast their SSID.
>I guess my Linksys monitor is a form
>of sniffer but all it does is list the ssid and strength, no
>other info is given. But it gives more than hopper.
Nope. It's an active monitor and uses probe requests just like
Netstumbler and WiFiHopper.
>Apparently the hopper didn't interfere with the Linksys
>monitor, it's still working the same.
Actually, it does interfere. When you have WiFiHopper running, it
shuts down any other connection manager including Windoze Wireless
Zero Config, and takes over using its own connection manager. Please
read the docs. This is fine except that after the connection manager
of the program expires after a month, it still kills the Windoze WZC
or any other connection manager when running. There are other
interactions that bug me. Every time it probes a live connection will
stall. The beta version had it probeing every 3 seconds which
resulted in a download practically stopping. Even set to the current
default (10 sec???) it will still slow down downloads. In short, you
can't really have it probeing for access points while trying to do
useful web surfing or downloading. Also, when exiting the program, it
will drop the connection. That's fine, but some drivers don't recover
very gracefully. I find myself rebooting a bit too often. Still,
it's a useful program if you don't try to do everything at once.
>Also the HELP menu item doesn't work so I can't really study
>how to use the thing. Maybe if I pay for it they will give
>me the help files.
Help works for me. However, I'm still running some old beta version.
I'll try a later version when my laptop isn't busy.
>So I still don't have anything that does much sniffing but
>I'll keep looking. Thanks for your input. Rob
Well, another possibility is to use Kismet running on a Linux LiveCD.
Nothing to install, just boot the CD. See:
<http://www.remote-exploit.org/backtrack.html>
707MBytes to download. Ugh.
The graph doesn't work either. It does bump along updating
"hits" on horiz axis but no graph line is seen. I presumed
it was just plotting constant -64dBm, which is on the lower
end of the vert axis. In any case, nothing interesting is
seen on the graph.
If SSID is something like "my Linksys", then yes, it is
being broadcast by my neighbor.
I just found some info on the wifihopper site, maybe that
will help me figure out how to use it -- since the program's
HELP doesn't exist.
I'm beginning to think something is weird with my laptop
system since I can't get netstumbler to do anything, and a
lot of others are able to use it OK. But at least it does
connect with the AP and hasn't broken down yet.
Thanks again.
Jeff Liebermann wrote:
>>The signal level it shows stays at -64dBm(/Mhz I presume)
>>even though I cover my antenna with my hand. My Linksys
>>measurement shows signal dropping but hopper level never
>>changes. Clearly it isn't finding the actual level.
>
>
> Use the graph, not the table to get your numbers. The table does not
> update in real time.
>
>
>>It doesn't find my neighbor's AP, no filters on.
>
>
> Are they broadcasting their SSID?
>
>
On Thu, 08 Mar 2007 12:46:56 -0600, rob <robIV@piovere.com> wrote in
<45f05a23$0$28070$4c368faf@roadrunner.com>:
>If SSID is something like "my Linksys", then yes, it is
>being broadcast by my neighbor.
You do have a _unique_ SSID set on your own network, right?
That's very important.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
Yes sir. Out of the box I had the default but now it's quite
unique -- after reading postings on this ng. Thanks.
John Navas wrote:
> On Thu, 08 Mar 2007 12:46:56 -0600, rob <robIV@piovere.com> wrote in
> <45f05a23$0$28070$4c368faf@roadrunner.com>:
>
>
>>If SSID is something like "my Linksys", then yes, it is
>>being broadcast by my neighbor.
>
>
> You do have a _unique_ SSID set on your own network, right?
> That's very important.
>
>
> Well, another possibility is to use Kismet running on a Linux LiveCD.
> Nothing to install, just boot the CD. See:
> <http://www.remote-exploit.org/backtrack.html>
> 707MBytes to download. Ugh.
>
If you are interested they have just released BT2 Final. The
auto-configure for Kismet works for my WG511T(Atheros) and Ralink2500
cards, in fact if both cards are fitted you get a choice of which one to
use. They have included a new sniffer called Wicrawl ,which I haven't
got to work with my cards yet. http://midnightresearch.com/projects/wicrawl/
kev wrote:
> Jeff Liebermann wrote:
>
>>
>> Well, another possibility is to use Kismet running on a Linux LiveCD.
>> Nothing to install, just boot the CD. See:
>> <http://www.remote-exploit.org/backtrack.html>
>> 707MBytes to download. Ugh.
>>
> If you are interested they have just released BT2 Final. The
> auto-configure for Kismet works for my WG511T(Atheros) and Ralink2500
> cards, in fact if both cards are fitted you get a choice of which one to
> use. They have included a new sniffer called Wicrawl ,which I haven't
> got to work with my cards yet.
> http://midnightresearch.com/projects/wicrawl/
>
Having had a further play I still can't get it to work with my Ralink
card, however I have got it to work with the WG511T.
1.Open console.
2.Type airmon-ng start wifi0 press enter.
3.This will report an ath in monitor mode, call it ath1 (due to playing
I was at ath3 for monitor mode).
4.Type ifconfig ath1 up press enter (It is important that you
use the one designated in monitor mode)
5.Start wicrawl ,go to Interfaces and make sure ath1 monitor mode is
ticked.
There seems to be a bug in the copy I have as the Channel reporting was
incorrect.
signal numbers off WPC54G make sense? 
Linear Mode
