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  #1 (permalink)  
Old 08-04-2007, 11:48 PM
Mark
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Posts: n/a
Default WiFi ping times fluctuating

Hi everyone, I've had a problem starting yesterday (at least that's
when I noticed it) where the wireless connection between my laptop and
(buffalo) router has not been reliable, and downloads have been very
slow.

When I try to ping the router, this is what happens:

PING 192.168.1.1 (192.168.1.1): 56 data bytes
64 bytes from 192.168.1.1: icmp_seq=0 ttl=64 time=2135.790 ms
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=1141.654 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=142.660 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=0.921 ms
64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=3132.532 ms
64 bytes from 192.168.1.1: icmp_seq=5 ttl=64 time=2132.499 ms
64 bytes from 192.168.1.1: icmp_seq=6 ttl=64 time=1133.152 ms
64 bytes from 192.168.1.1: icmp_seq=7 ttl=64 time=133.306 ms
64 bytes from 192.168.1.1: icmp_seq=8 ttl=64 time=0.923 ms
64 bytes from 192.168.1.1: icmp_seq=9 ttl=64 time=3132.179 ms
64 bytes from 192.168.1.1: icmp_seq=10 ttl=64 time=2132.909 ms
64 bytes from 192.168.1.1: icmp_seq=11 ttl=64 time=1132.991 ms
64 bytes from 192.168.1.1: icmp_seq=12 ttl=64 time=132.959 ms
64 bytes from 192.168.1.1: icmp_seq=13 ttl=64 time=0.944 ms
64 bytes from 192.168.1.1: icmp_seq=14 ttl=64 time=3132.797 ms
64 bytes from 192.168.1.1: icmp_seq=15 ttl=64 time=2132.787 ms
64 bytes from 192.168.1.1: icmp_seq=18 ttl=64 time=0.895 ms

Most of the packets are transmitted fine, but the ping times fluctuate
from pretty reasonable (sub-one second) and pretty awful (over three
seconds).

Does anyone have any idea why this might be happening? I've tried
turning WPA off, putting the laptop right next to the router, and
changing the wifi channel, with no success.

Appreciate your thoughts!


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  #2 (permalink)  
Old 08-04-2007, 11:58 PM
Jeff Liebermann
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Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 4, 4:48 pm, Mark <markjtur...@gmail.com> wrote:
> Hi everyone, I've had a problem starting yesterday (at least that's
> when I noticed it) where the wireless connection between my laptop and
> (buffalo) router has not been reliable, and downloads have been very
> slow.
>
> When I try to ping the router, this is what happens:
>
> PING 192.168.1.1 (192.168.1.1): 56 data bytes
> 64 bytes from 192.168.1.1: icmp_seq=0 ttl=64 time=2135.790 ms
> 64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=1141.654 ms
> 64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=142.660 ms
> 64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=0.921 ms
> 64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=3132.532 ms
> 64 bytes from 192.168.1.1: icmp_seq=5 ttl=64 time=2132.499 ms
> 64 bytes from 192.168.1.1: icmp_seq=6 ttl=64 time=1133.152 ms
> 64 bytes from 192.168.1.1: icmp_seq=7 ttl=64 time=133.306 ms
> 64 bytes from 192.168.1.1: icmp_seq=8 ttl=64 time=0.923 ms
> 64 bytes from 192.168.1.1: icmp_seq=9 ttl=64 time=3132.179 ms
> 64 bytes from 192.168.1.1: icmp_seq=10 ttl=64 time=2132.909 ms
> 64 bytes from 192.168.1.1: icmp_seq=11 ttl=64 time=1132.991 ms
> 64 bytes from 192.168.1.1: icmp_seq=12 ttl=64 time=132.959 ms
> 64 bytes from 192.168.1.1: icmp_seq=13 ttl=64 time=0.944 ms
> 64 bytes from 192.168.1.1: icmp_seq=14 ttl=64 time=3132.797 ms
> 64 bytes from 192.168.1.1: icmp_seq=15 ttl=64 time=2132.787 ms
> 64 bytes from 192.168.1.1: icmp_seq=18 ttl=64 time=0.895 ms
>
> Most of the packets are transmitted fine, but the ping times fluctuate
> from pretty reasonable (sub-one second) and pretty awful (over three
> seconds).
>
> Does anyone have any idea why this might be happening? I've tried
> turning WPA off, putting the laptop right next to the router, and
> changing the wifi channel, with no success.
>
> Appreciate your thoughts!


I can't tell what's causing the problem, mostly because I don't
have a clue as to what you have for hardware, but the problem
is obviously packet loss. Wireless routers work on two levels
(layers). At the MAC layer, you only see the longer time delays
caused by the packet loss. Packets are retransmitted transparently.
So, at the IP layer, you get somewhat reliable delivery, but with
the observed time delays. My guess is that you have a neighbor
that just dragged home a new wireless router.

The standard fixes for interference problems are to change the
RF channel or play with directional antennas. Putting your laptop
next to the wireless router isn't going to do anything if either
is hearing the interference. Not much I can suggest until you
identify the source of the interference.



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  #3 (permalink)  
Old 08-05-2007, 12:17 AM
Mark
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Posts: n/a
Default Re: WiFi ping times fluctuating

Hi Jeff, thanks for the suggestions. That's interesting that it would
report packets as delivered when actually they were dropping, I didn't
know that. What kind of hardware details would help?

There a couple of other wireless networks in the area, probably
neighbours, but they're on channel 6 and I'm on channel 11. I've tried
setting it to channel 1 as well and it's the same. What else could be
causing interference? The router is quite near my TV and stuff, could
that be causing the problem?


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  #4 (permalink)  
Old 08-05-2007, 12:31 AM
Jeff Liebermann
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Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 4, 5:17 pm, Mark <markjtur...@gmail.com> wrote:
> Hi Jeff, thanks for the suggestions. That's interesting that it would
> report packets as delivered when actually they were dropping, I didn't
> know that.


Layer 2 diagnostics (MAC layer) are very rare in commodity
wireless. The IP layer never sees the retransmissions.
All it sees are longer delays.

>What kind of hardware details would help?


Maker and model of router. Hardware version. Firmware version
optional.
Maker and model of test client laptop.
Some clue as to the topology, neighborhood, etc.
Is the interference continuous or intermittent? Times?

Incidentally, go down this list of probable culprits and see
if any look new.
<http://wireless.wikia.com/wiki/Wi-Fi#Interference>
Municipal wireless installation seem to be becoming a
problem.

> There a couple of other wireless networks in the area, probably
> neighbours, but they're on channel 6 and I'm on channel 11. I've tried
> setting it to channel 1 as well and it's the same. What else could be
> causing interference? The router is quite near my TV and stuff, could
> that be causing the problem?


See list above. Also, you can't "see" a wireless network that
doesn't broadcast its SSID. You can use Kismet to sniff these,
or a spectrum analyzer:
<http://www.metageek.net/Products/Wi-Spy>
There are also some MIMO (802.11n) networks that don't show
up on a client utility or active scanner.

If your radios are near a window, try moving the access point
and/or client away from the window. That's the most likely
point of entry.



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  #5 (permalink)  
Old 08-05-2007, 12:59 AM
Mark
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 5, 1:31 am, Jeff Liebermann <je...@comix.santa-cruz.ca.us>
wrote:
> On Aug 4, 5:17 pm, Mark <markjtur...@gmail.com> wrote:
>
> > Hi Jeff, thanks for the suggestions. That's interesting that it would
> > report packets as delivered when actually they were dropping, I didn't
> > know that.

>
> Layer 2 diagnostics (MAC layer) are very rare in commodity
> wireless. The IP layer never sees the retransmissions.
> All it sees are longer delays.
>
> >What kind of hardware details would help?

>
> Maker and model of router. Hardware version. Firmware version
> optional.
> Maker and model of test client laptop.
> Some clue as to the topology, neighborhood, etc.
> Is the interference continuous or intermittent? Times?
>


The router is buffalo whr-g54s, according to the web interface it is:
WHR-HP-G54 Ver.1.40 (1.0.37-1.08-1.04)

My laptop is an apple macbook pro, just over a year old.

I live in a small city in the uk, I'm pretty sure there's no municipal
wifi here.

The problem I'm experiencing is constant, every time I've pinged the
router over the last two days I've seen the same thing.

> Incidentally, go down this list of probable culprits and see
> if any look new.
> <http://wireless.wikia.com/wiki/Wi-Fi#Interference>
> Municipal wireless installation seem to be becoming a
> problem.
>
> > There a couple of other wireless networks in the area, probably
> > neighbours, but they're on channel 6 and I'm on channel 11. I've tried
> > setting it to channel 1 as well and it's the same. What else could be
> > causing interference? The router is quite near my TV and stuff, could
> > that be causing the problem?

>
> See list above. Also, you can't "see" a wireless network that
> doesn't broadcast its SSID. You can use Kismet to sniff these,
> or a spectrum analyzer:
> <http://www.metageek.net/Products/Wi-Spy>
> There are also some MIMO (802.11n) networks that don't show
> up on a client utility or active scanner.


I've got istumbler on my mac which I believe is similar to kismet.

>
> If your radios are near a window, try moving the access point
> and/or client away from the window. That's the most likely
> point of entry.


The router is quite near a window, I've tried moving it away a bit
(it's about 10 feet away now) and that doesn't seem to have helped.

Appreciate your guidance Jeff, thanks.


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  #6 (permalink)  
Old 08-05-2007, 02:55 AM
Jeff Liebermann
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Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 4, 5:59 pm, Mark <markjtur...@gmail.com> wrote:

> The router is buffalo whr-g54s, according to the web interface it is:
> WHR-HP-G54 Ver.1.40 (1.0.37-1.08-1.04)


Not exactly. The WHR-HP-G4 and WHR-G54S are two different
products. The "HP" for high power version has higher tx power
output. I like these units and use them with DD-WRT firmware.

> I live in a small city in the uk, I'm pretty sure there's no municipal
> wifi here.


Well, muni wireless was just a guess. There's a long list
of other sources of interference. The reason I asked about
the timing is that many sources are intermittent in timing.
For example, a microwave oven interferes for about 10 minutes,
with long pauses in between.


> The problem I'm experiencing is constant, every time I've pinged the
> router over the last two days I've seen the same thing.


That eliminates about half the list.
A "small city" isn't very useful, but if you see any metro wireless
security cameras, they may also be a source of interference.

> I've got istumbler on my mac which I believe is similar to kismet.


Nope. Istumbler and Netstumbler are active sniffers. They
transmit probe requests, and listen for responses. Kismet
is also a passive sniffer. It listens for traffic but does not
transmit. I stumbler will not show an access point that is
NOT broadcasting its SSID.

> The router is quite near a window, I've tried moving it away a bit
> (it's about 10 feet away now) and that doesn't seem to have helped.


Well, I think it might be useful to test this in an isolated location,
known to be interference free, such as a basement. Just the
Buffalo and the Mac laptop. If it screws up in the basement,
then there's something wrong with the hardware.



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  #7 (permalink)  
Old 08-06-2007, 12:51 PM
Mark
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 5, 3:55 am, Jeff Liebermann <je...@comix.santa-cruz.ca.us>
wrote:
> On Aug 4, 5:59 pm, Mark <markjtur...@gmail.com> wrote:
>
> > The router is buffalo whr-g54s, according to the web interface it is:
> > WHR-HP-G54 Ver.1.40 (1.0.37-1.08-1.04)

>
> Not exactly. The WHR-HP-G4 and WHR-G54S are two different
> products. The "HP" for high power version has higher tx power
> output. I like these units and use them with DD-WRT firmware.
>
> > I live in a small city in the uk, I'm pretty sure there's no municipal
> > wifi here.

>
> Well, muni wireless was just a guess. There's a long list
> of other sources of interference. The reason I asked about
> the timing is that many sources are intermittent in timing.
> For example, a microwave oven interferes for about 10 minutes,
> with long pauses in between.
>
> > The problem I'm experiencing is constant, every time I've pinged the
> > router over the last two days I've seen the same thing.

>
> That eliminates about half the list.
> A "small city" isn't very useful, but if you see any metro wireless
> security cameras, they may also be a source of interference.
>
> > I've got istumbler on my mac which I believe is similar to kismet.

>
> Nope. Istumbler and Netstumbler are active sniffers. They
> transmit probe requests, and listen for responses. Kismet
> is also a passive sniffer. It listens for traffic but does not
> transmit. I stumbler will not show an access point that is
> NOT broadcasting its SSID.
>
> > The router is quite near a window, I've tried moving it away a bit
> > (it's about 10 feet away now) and that doesn't seem to have helped.

>
> Well, I think it might be useful to test this in an isolated location,
> known to be interference free, such as a basement. Just the
> Buffalo and the Mac laptop. If it screws up in the basement,
> then there's something wrong with the hardware.


Hmm, well unfortunately I don't have a basement.

I have tried kismac, but it doesn't seem to work well, I've heard it
has compatibility problems with newer macbooks so maybe that's why.

Do you think trying a high-gain antenna would be a good idea? To try
and overpower the interference?

Appreciate your insight Jeff, I feel like I understand the issues a
lot better now, but I am starting to feel like I might just have to
learn to live with the problem :-(


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  #8 (permalink)  
Old 08-06-2007, 08:36 PM
Jeff Liebermann
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 6, 5:51 am, Mark <markjtur...@gmail.com> wrote:

> Hmm, well unfortunately I don't have a basement.


Do you have a shovel? Never mind. My humor skills
are temporarily impaired.

> I have tried kismac, but it doesn't seem to work well, I've heard it
> has compatibility problems with newer macbooks so maybe that's why.


I previously suggested. If you can't find anything that will work
on the MacBook, then I was hoping that you would consider
dragging your wireless router and MacBook to some isolated
location know to be devoid of 2.4GHz interference or surrounded
by sufficient quantities of dirt to be effectively shielded. What
you're doing is determining if it's really interference, or if it's a
weak signal to the wireless router, or a some configuration
problem on the router or MacBook. You decide if it's worth the
exercise.

> Do you think trying a high-gain antenna would be a good idea? To try
> and overpower the interference?


Probably not. Lots of problems.
1. An omnidirectional antenna will increase the signal strength of
both the interference and the MacBook.
2. A directional antenna will help, but only if you know what
direction
the interference is coming from.
3. You still don't know if it's really interference, or something in
the
router or MacBook.
4. You don't know if the interference is entering the system at the
router end, or the MacBook end. The resultant packet loss will
be similar.

Once you've determined the source of the interference, only then can
you take remedial action. However, it might be useful to try a
directional
antenna at one or both ends. If you can see the interference as an
increase in "noise level" reported by the wireless client, you might
be
able to determine the direction of the source.

Incidentally, someone once wrote that their local source of
interference
turned out to be their new wireless doorbell receiver.

> Appreciate your insight Jeff, I feel like I understand the issues a
> lot better now, but I am starting to feel like I might just have to
> learn to live with the problem :-(


Perhaps the shovel wasn't such a bad idea.




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  #9 (permalink)  
Old 08-06-2007, 11:45 PM
Mark
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On 6 Aug, 21:36, Jeff Liebermann <je...@comix.santa-cruz.ca.us> wrote:
> On Aug 6, 5:51 am, Mark <markjtur...@gmail.com> wrote:
>
> > Hmm, well unfortunately I don't have a basement.

>
> Do you have a shovel? Never mind. My humor skills
> are temporarily impaired.
>
> > I have tried kismac, but it doesn't seem to work well, I've heard it
> > has compatibility problems with newer macbooks so maybe that's why.

>
> I previously suggested. If you can't find anything that will work
> on the MacBook, then I was hoping that you would consider
> dragging your wireless router and MacBook to some isolated
> location know to be devoid of 2.4GHz interference or surrounded
> by sufficient quantities of dirt to be effectively shielded. What
> you're doing is determining if it's really interference, or if it's a
> weak signal to the wireless router, or a some configuration
> problem on the router or MacBook. You decide if it's worth the
> exercise.
>
> > Do you think trying a high-gain antenna would be a good idea? To try
> > and overpower the interference?

>
> Probably not. Lots of problems.
> 1. An omnidirectional antenna will increase the signal strength of
> both the interference and the MacBook.
> 2. A directional antenna will help, but only if you know what
> direction
> the interference is coming from.
> 3. You still don't know if it's really interference, or something in
> the
> router or MacBook.
> 4. You don't know if the interference is entering the system at the
> router end, or the MacBook end. The resultant packet loss will
> be similar.
>
> Once you've determined the source of the interference, only then can
> you take remedial action. However, it might be useful to try a
> directional
> antenna at one or both ends. If you can see the interference as an
> increase in "noise level" reported by the wireless client, you might
> be
> able to determine the direction of the source.
>
> Incidentally, someone once wrote that their local source of
> interference
> turned out to be their new wireless doorbell receiver.
>
> > Appreciate your insight Jeff, I feel like I understand the issues a
> > lot better now, but I am starting to feel like I might just have to
> > learn to live with the problem :-(

>
> Perhaps the shovel wasn't such a bad idea.


Ok, I think I will take my router over to my girlfriend's house and
try it out there, at least then I'll know if it's a hardware problem
or not. I can try connecting to it from her computer as well and see
if I have any success.

I've tried taking the macbook to the other end of the house, but no
difference. Would it be worth plugging the router in in a different
room?

Then if it turns out it is interference-related, do you reckon it
would be possible to use tin foil instead of dirt to achieve much the
same effect? Can I improvise a directional aerial from a wok or
something?


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  #10 (permalink)  
Old 08-07-2007, 04:38 AM
Jeff Liebermann
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 6, 4:45 pm, Mark <markjtur...@gmail.com> wrote:
(trimmed...)

> Ok, I think I will take my router over to my girlfriend's house and
> try it out there, at least then I'll know if it's a hardware problem
> or not. I can try connecting to it from her computer as well and see
> if I have any success.


Well, if you're going to do that, you might want to try doing
some benchmarking over the wireless link. See IPerf at:
<http://dast.nlanr.net/Projects/Iperf/#download>
If you search this newsgroup for my postings on IPerf, you'll
find instructions and sample output.

> I've tried taking the macbook to the other end of the house, but no
> difference. Would it be worth plugging the router in in a different
> room?


Dunno. I was looking for a location that was guaranteed to have
no interference sources at either end. That means moving both
the MacBook and router. I don't think it will be worth the effort.

> Then if it turns out it is interference-related, do you reckon it
> would be possible to use tin foil instead of dirt to achieve much the
> same effect? Can I improvise a directional aerial from a wok or
> something?


Sure. See home made reflectors at:
<http://www.freeantennas.com>
However, the problem will be where to aim the antenna. If you
can't identify the source, some tinkering and trial and error will
probably suffice.




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  #11 (permalink)  
Old 08-07-2007, 05:49 PM
Mark
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

Well, this morning I happened to turn off my computer and when I
turned it on again this evening, I noticed the problem had resolved
itself. In hindsight I probably should have thought of restarting my
computer before...

I'm now hoping that it's actually fixed and doesn't come back, or I
might have to break out that shovel!

Anyway, I wanted to thank you Jeff for your patience and knowledge,
I've found your pointers helpful in understanding this technology
better, which I'm sure will come in useful in future!

Cheers!


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  #12 (permalink)  
Old 08-07-2007, 06:00 PM
Jeff Liebermann
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Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 7, 10:49 am, Mark <markjtur...@gmail.com> wrote:
> Well, this morning I happened to turn off my computer and when I
> turned it on again this evening, I noticed the problem had resolved
> itself. In hindsight I probably should have thought of restarting my
> computer before...


Sigh. So much for the interference theory. I sorta assumed
that you had power cycled everything. I think you can safely
put away the shovel.

However, I do have a solution. Just run Windoze XP as your primary
operating system. It has to be rebooted far more often than OS/X
so you won't see such problems.



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  #13 (permalink)  
Old 08-07-2007, 06:36 PM
Larry Finger
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

Jeff Liebermann wrote:
> On Aug 7, 10:49 am, Mark <markjtur...@gmail.com> wrote:
>> Well, this morning I happened to turn off my computer and when I
>> turned it on again this evening, I noticed the problem had resolved
>> itself. In hindsight I probably should have thought of restarting my
>> computer before...

>
> Sigh. So much for the interference theory. I sorta assumed
> that you had power cycled everything. I think you can safely
> put away the shovel.
>
> However, I do have a solution. Just run Windoze XP as your primary
> operating system. It has to be rebooted far more often than OS/X
> so you won't see such problems.


I love that answer. I'll save it as a response whenever anyone asks me "why should I run Windows".
Is it trademarked, or just copylefted?

Larry

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  #14 (permalink)  
Old 08-07-2007, 09:33 PM
Jeff Liebermann
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 7, 11:36 am, Larry Finger <Larry.Fin...@lwfinger.net> wrote:
> Jeff Liebermann wrote:
> > However, I do have a solution. Just run Windoze XP as your primary
> > operating system. It has to be rebooted far more often than OS/X
> > so you won't see such problems.


> I love that answer. I'll save it as a response whenever anyone asks me "why should I run Windows".
> Is it trademarked, or just copylefted?
> Larry


Neither. It's all yours. I'm a bit jealous of the stability of OS/X
machines. I've seen them go for months without a reboot.
I can almost do that with Windoze, but nowhere nearly as long
or as well. My background is mostly SCO Xenix and Unix
systems. I had systems that had uptimes of over a year
without a reboot. That includes CAD workstations and some
desktops. However, the current plague of security
updates and patches has largely prevented long term uptime
testing. Mean time between updates that require a reboot
is about a month and dropping.

At one point, there was a bug fix for Windoze 98 that involved
a timer counter overflow and subsequent crash after something
like 60 days. I couldn't find the reference, but it's real. The
joke
was that nobody had experienced this bug because Windoze
systems just didn't stay up that long.

Someone always asks why I deal with Windoze when there are
better alternatives. Well, I have to make money, and I don't
make money repairing systems that work well. So, I do Windoze,
which offers me the maximum revenue flow and largest customer
base. The company motto is "If this stuff worked, you wouldn't
need me".

I would be negligent if I didn't offer some light Mac bashing.
I don't have a problem with the Mac hardware or software.
Unix is good no matter how it's packaged and buried under
a GUI. It's the customers that drive me nuts. Apple makes it
sound like running a Mac is so easy and reliable, that if something
goes obviously wrong, it's probably the customers fault. The result
is that customers blame themselves all too often and simply
don't seek help until they're over their heads. Since I'm in the
business of providing help, this is a bad thing for business.




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  #15 (permalink)  
Old 08-08-2007, 01:33 AM
Larry Finger
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

Jeff Liebermann wrote:
> On Aug 7, 11:36 am, Larry Finger <Larry.Fin...@lwfinger.net> wrote:
>
> Neither. It's all yours. I'm a bit jealous of the stability of OS/X
> machines. I've seen them go for months without a reboot.
> I can almost do that with Windoze, but nowhere nearly as long
> or as well. My background is mostly SCO Xenix and Unix
> systems. I had systems that had uptimes of over a year
> without a reboot. That includes CAD workstations and some
> desktops. However, the current plague of security
> updates and patches has largely prevented long term uptime
> testing. Mean time between updates that require a reboot
> is about a month and dropping.


I had a Linux machine functioning as a file and print server and as a router between 22 Windows
computers and the Internet in a computer lab. It and the DSL modem were plugged into a UPS with
enough capacity to ride out the interruptions that happened in Phoenix in the summer and was up for
18 months. It was shut down when the room was gutted and remodeled.

> At one point, there was a bug fix for Windoze 98 that involved
> a timer counter overflow and subsequent crash after something
> like 60 days. I couldn't find the reference, but it's real. The
> joke
> was that nobody had experienced this bug because Windoze
> systems just didn't stay up that long.


I heard it was 180 days. However long, someone had to find it from analyzing the code, not a crash dump.

> Someone always asks why I deal with Windoze when there are
> better alternatives. Well, I have to make money, and I don't
> make money repairing systems that work well. So, I do Windoze,
> which offers me the maximum revenue flow and largest customer
> base. The company motto is "If this stuff worked, you wouldn't
> need me".


Clearly Windoze is a good deal for the repairers and Bill Gates.

> I would be negligent if I didn't offer some light Mac bashing.
> I don't have a problem with the Mac hardware or software.
> Unix is good no matter how it's packaged and buried under
> a GUI. It's the customers that drive me nuts. Apple makes it
> sound like running a Mac is so easy and reliable, that if something
> goes obviously wrong, it's probably the customers fault. The result
> is that customers blame themselves all too often and simply
> don't seek help until they're over their heads. Since I'm in the
> business of providing help, this is a bad thing for business.


Some users can be awful. In the old days, before OS X, I had one guy that managed to blow away the
OS on his Mac regularly - about once a month. Tragically, he died and the person that inherited that
machine never had the problem. I have no idea what he was doing, but I had to keep the CD handy.

Larry

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  #16 (permalink)  
Old 08-08-2007, 05:01 AM
NotMe
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating


"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
news:1186432560.165410.297310@z24g2000prh.googlegr oups.com...
| On Aug 6, 5:51 am, Mark <markjtur...@gmail.com> wrote:
|
| > Hmm, well unfortunately I don't have a basement.
|
| Do you have a shovel? Never mind. My humor skills
| are temporarily impaired.
|
| > I have tried kismac, but it doesn't seem to work well, I've heard it
| > has compatibility problems with newer macbooks so maybe that's why.
|
| I previously suggested. If you can't find anything that will work
| on the MacBook, then I was hoping that you would consider
| dragging your wireless router and MacBook to some isolated
| location know to be devoid of 2.4GHz interference or surrounded
| by sufficient quantities of dirt to be effectively shielded. What
| you're doing is determining if it's really interference, or if it's a
| weak signal to the wireless router, or a some configuration
| problem on the router or MacBook. You decide if it's worth the
| exercise.
|
| > Do you think trying a high-gain antenna would be a good idea? To try
| > and overpower the interference?
|
| Probably not. Lots of problems.
| 1. An omnidirectional antenna will increase the signal strength of
| both the interference and the MacBook.
| 2. A directional antenna will help, but only if you know what
| direction
| the interference is coming from.
| 3. You still don't know if it's really interference, or something in
| the
| router or MacBook.
| 4. You don't know if the interference is entering the system at the
| router end, or the MacBook end. The resultant packet loss will
| be similar.
|
| Once you've determined the source of the interference, only then can
| you take remedial action. However, it might be useful to try a
| directional
| antenna at one or both ends. If you can see the interference as an
| increase in "noise level" reported by the wireless client, you might
| be
| able to determine the direction of the source.
|
| Incidentally, someone once wrote that their local source of
| interference
| turned out to be their new wireless doorbell receiver.
|
| > Appreciate your insight Jeff, I feel like I understand the issues a
| > lot better now, but I am starting to feel like I might just have to
| > learn to live with the problem :-(
|
| Perhaps the shovel wasn't such a bad idea.

Some of the Mac laptops have metal cases and that screws up wifi
performance.



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  #17 (permalink)  
Old 08-08-2007, 05:42 AM
Jeff Liebermann
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 7, 10:01 pm, "NotMe" <m...@privacy.net> wrote:
(Trimmed. Please learn to use a text editor...)
> Some of the Mac laptops have metal cases and that screws up wifi
> performance.


That would be the original PowerBooks. The 17" and 15"
G4 models allow external antennas. The 12" does not
but can be butchered:
<http://www.instructables.com/id/EHDHDZ2MCCEP2868FX/>

Some plastic cases have aluminized paint for EMI/RFI shielding
on the inside of the case. As far as I can tell, most current
laptops have the antennas in the upper part of the LCD
display and do not have much of a shielding problem.

How about a Bic Pen antenna?
<http://www.inventiondb.com/browse.php?cubeid=1041&tabid=&stabid=0>

External antenna mods, including a few Apple products.
<http://repair4laptop.org/wireless_lan_antennae.html>




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  #18 (permalink)  
Old 08-08-2007, 10:44 AM
dold@93.usenet.us.com
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:

> How about a Bic Pen antenna?
> <http://www.inventiondb.com/browse.php?cubeid=1041&tabid=&stabid=0>


That's an odd presentation, unless I missed some clicks.
There is almost as much construction information in your one line
introduction as there is on the page.

Using an MMCX RG174 pigtail (.110"), you can follow instructions available
on the internet for making a Collinear WiFi antenna using a Bic pen barrel
as the outer housing, maybe adding a "binder clip" as a base stand for the
upright antenna. I would have used the unmodified binder clip in a
different orientation, but maybe that wouldn't work as well as I think.

http://martybugs.net/wireless/antennacomp.cgi
http://wireless.gumph.org/articles/homemadeomni.html

Or, if all you need is to get the antenna outside of the case, Don Widders
suggests "the simplest antenna", using LMR195 cable (.037" diameter).

Remove about 3 inches of the plastic outer 'jacket' of the coax. Then pull
the copper braid back over the remaining jacket. Get a piece of brass
tubing at a hobby shop that will just slide over the braid and cut a piece
of the tubing to 32 mm. Trim away any excess braid. Cut the center
conductor so that it extends exactly 32 mm from where it exits from the
braid.

A chunk of cable (LMR195?) with two MMCX connectors:
http://www.echotechwireless.com/prod...-mmcx-mmcx.htm

--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5

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  #19 (permalink)  
Old 08-08-2007, 05:37 PM
Jeff Liebermann
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 8, 3:44 am, d...@93.usenet.us.com wrote:
> Jeff Liebermann <je...@comix.santa-cruz.ca.us> wrote:
> > How about a Bic Pen antenna?
> > <http://www.inventiondb.com/browse.php?cubeid=1041&tabid=&stabid=0>

>
> That's an odd presentation, unless I missed some clicks.
> There is almost as much construction information in your one line
> introduction as there is on the page.


Well, yeah, you're right. It's not exactly a construction article.
I thought it was cute and clever. If you want to build one, it's
easily done with just coax cable. What you do is strip back the
coax cable 1/4 wavelength (3.25cm) and pull the insulation back
over the outer coax jacket. This forms a "coaxial antenna"
which is what's inside most 2dBi rubber ducky antennas.
Cheap, crude, and functional.

For example, this is the guts of a typical 2.4ghz 2dBi antenna:
<http://802.11junk.com/jeffl/antennas/coaxial/slides/coax-ant.html>
This uses a brass tube instead of the braid, which generally
more stable and easier to work with. If you look carefully, you'll
notice that the length of the exposed center conductor is
roughly 3.25cm, but the brass tube counterpoise appears to
be considerably shorter. That's because you measure the
counterpoise length from the center conductor, at an angle
for a while, and then straight down.

What you do for an outside package is left to the imagination.
However, its composition does affect radiation and cut lengths.
Just about everything has a "velocity factor" the causes RF
to slow down in a dielectric. If you build and test this antenna
in the open, and then slide a plastic tube over it, the resonant
(center) frequency will shift downward somewhat. This effect
can be calculated for various materials and sizes, but is best
done by cut-n-try. Incidentally, this is the reason commercial
2.4GHz omnis use fiberglass tubes, instead of the much cheaper
white PVC pipe.

The effects of the velocity factor vary with the size of the
conductor. That's another reason why the exposed center
conductor is almost exactly 3.25cm, while the sleeve
counterpoise is much shorter. The tendency for the outer
jacket to cause a downward frequency shift is compensated
by a shortening of the antenna elements. But, because the
effect is more pronounced with the larger counterpoise, it
needs to be shorter than the driven element.

> http://martybugs.net/wireless/antennacomp.cgi


Umm... why did you include this URL?
I have some issues with this "comparison" article. The test
antenna are way too close to the ground to avoid the effects
of reflections. They also put the ground well inside the
Fresnel Zone for the 200m test range. In addition, the
construction of Biquad 1 is wrong, but seems to have
been used by other creative antenna builders. I've covered
both issues in previous rants.

> http://wireless.gumph.org/articles/homemadeomni.html


I've built and tested roughly 3 variations of this technique.
The problem is that it results in an antenna that is twice
as long as necessary for the same gain. If the designer
had use coils or stubs as delay elements instead of coax
sections, then the antenna would be much smaller. It
also suffers from coax loss problems, and cumulative
errors from multiple precision cuts and soldering connection.
Yeah, they work, but why bother?

> Or, if all you need is to get the antenna outside of the case, Don Widders
> suggests "the simplest antenna", using LMR195 cable (.037" diameter).
>
> Remove about 3 inches of the plastic outer 'jacket' of the coax. Then pull
> the copper braid back over the remaining jacket. Get a piece of brass
> tubing at a hobby shop that will just slide over the braid and cut a piece
> of the tubing to 32 mm. Trim away any excess braid. Cut the center
> conductor so that it extends exactly 32 mm from where it exits from the
> braid.


Bingo. That's roughly what I was mumbling about in my disection
of the 2dBi rubber ducky antenna. However, if he actually tested
the antenna with a swept reflection bridge, methinks he would have
found the tubing to be somewhat shorter than 32 mm.

> A chunk of cable (LMR195?) with two MMCX connectors:
> http://www.echotechwireless.com/prod...-mmcx-mmcx.htm


No way. My guess(tm) is RG-316 with a much smaller
diameter then LMR-195.

BTW: I survived in grand style. So far so good. I should know
in a few days if there are any complications. Once that I happens,
I party, followed by an RF test equipment shopping spree on eBay.



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  #20 (permalink)  
Old 08-08-2007, 05:44 PM
Jeff Liebermann
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

On Aug 8, 10:37 am, Jeff Liebermann <je...@comix.santa-cruz.ca.us>
wrote:
> > > How about a Bic Pen antenna?
> > > <http://www.inventiondb.com/browse.php?cubeid=1041&tabid=&stabid=0>


> > That's an odd presentation, unless I missed some clicks.
> > There is almost as much construction information in your one line
> > introduction as there is on the page.


I just found the photo of what's inside the Bic pen.
Click on the "more images" thing under the photo.
It's NOT what I expected.


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  #21 (permalink)  
Old 08-08-2007, 11:06 PM
NotMe
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating


"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
news:1186551730.571207.202870@x35g2000prf.googlegr oups.com...
| On Aug 7, 10:01 pm, "NotMe" <m...@privacy.net> wrote:
| (Trimmed. Please learn to use a text editor...)
| > Some of the Mac laptops have metal cases and that screws up wifi
| > performance.
|
| That would be the original PowerBooks. The 17" and 15"
| G4 models allow external antennas. The 12" does not
| but can be butchered:
| <http://www.instructables.com/id/EHDHDZ2MCCEP2868FX/>

Our 17" G4s (note the 's') are 2 to four years old and none have the option
of externam antenna that I can see. Am I missing something?



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  #22 (permalink)  
Old 08-09-2007, 12:55 AM
dold@93.usenet.us.com
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
> I just found the photo of what's inside the Bic pen.
> Click on the "more images" thing under the photo.
> It's NOT what I expected.


It looked like a little coax collinear, which is why I leaned toward that
on the web search. If someone wanted to make _this_ Bic antenna, the other
articles would give the construction hints needed.

--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5

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  #23 (permalink)  
Old 08-09-2007, 01:09 AM
dold@93.usenet.us.com
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
> Well, yeah, you're right. It's not exactly a construction article.
> I thought it was cute and clever. If you want to build one, it's
> easily done with just coax cable. What you do is strip back the
> coax cable 1/4 wavelength (3.25cm) and pull the insulation back
> over the outer coax jacket. This forms a "coaxial antenna"
> which is what's inside most 2dBi rubber ducky antennas.
> Cheap, crude, and functional.


That would be my thought, but the Bic was a collinear. I did mention the
"simple" antenna below.

> What you do for an outside package is left to the imagination.


And the Bic pen is ever-so-cute. Maybe the cantenna.com folks will start
selling them ;-)

> However, its composition does affect radiation and cut lengths.
> Just about everything has a "velocity factor" the causes RF
> to slow down in a dielectric.


I couldn't even find the I.D. of a Bic barrel online, other than in
reference to Kryptonite locks... bad memories of the empty spot on my desk
where the laptop used to be come floating back... What do you think the
velocity factor of Bic material is ;-)

> > http://martybugs.net/wireless/antennacomp.cgi


> Umm... why did you include this URL?


It had a link to a Collinear as well as other antenna types. I remembered
you and Marty in the same section of my memory, but I couldn't recall if it
was good or bad at 3 am.

> > http://wireless.gumph.org/articles/homemadeomni.html


> I've built and tested roughly 3 variations of this technique.


I only picked it because it looked like the inside of the Bic.

> Yeah, they work, but why bother?


It looks like way too much work. I'd be inclined to find someone's junk
router or client adapter with a nice antenna and a MMCX connector instead.

My laptop seems to have two bar antennas, one along the top of the LCD, one
along the right side. Very effective.

> > A chunk of cable (LMR195?) with two MMCX connectors:
> > http://www.echotechwireless.com/prod...-mmcx-mmcx.htm


> No way. My guess(tm) is RG-316 with a much smaller
> diameter then LMR-195.


I was just thinking of someone else putting that little tiny connector on
the end of the cable for me. I still don't know the size of a BIC barrel,
but if the 174 that the Bic poster mentions (I think he did), is bigger
than this, that means this would fit. Buying a cable with two MMCX
connectors seemed like a good idea.

> BTW: I survived in grand style. So far so good. I should know
> in a few days if there are any complications. Once that I happens,
> I party, followed by an RF test equipment shopping spree on eBay.


You're easy to please ;-) If you are typing coherently, that's a plus.
I didn't want to tell you what happened medically at my house recently.

--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5

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  #24 (permalink)  
Old 08-09-2007, 12:16 PM
dold@93.usenet.us.com
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
> How about a Bic Pen antenna?
> <http://www.inventiondb.com/browse.php?cubeid=1041&tabid=&stabid=0>


http://www.fab-corp.com/product.php?...cat=282&page=1
An antenna with a cable, costs less than the cable and connector needed to
make the Bic antenna, although it isn't as cute.

--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5

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  #25 (permalink)  
Old 08-09-2007, 06:46 PM
Jeff Liebermann
Guest
 
Posts: n/a
Default Re: WiFi ping times fluctuating

"NotMe" <me@privacy.net> hath wroth:

>
>"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
>news:1186551730.571207.202870@x35g2000prf.googleg roups.com...
>| On Aug 7, 10:01 pm, "NotMe" <m...@privacy.net> wrote:
>| (Trimmed. Please learn to use a text editor...)
>| > Some of the Mac laptops have metal cases and that screws up wifi
>| > performance.
>|
>| That would be the original PowerBooks. The 17" and 15"
>| G4 models allow external antennas. The 12" does not
>| but can be butchered:
>| <http://www.instructables.com/id/EHDHDZ2MCCEP2868FX/>


>Our 17" G4s (note the 's') are 2 to four years old and none have the option
>of externam antenna that I can see. Am I missing something?


Well, I've only torn into one G4 PowerBook, and it wasn't for anything
wireless. What I did was recycle the comments at:
<http://www.instructables.com/id/EHDHDZ2MCCEP2868FX/>
"Unfortunately, only 15" and 17" Powerbooks facilitate adding
your own external antenna. With just a few quick cuts you can
modify a 12" Powerbook to take an external antenna as well."

I think "facilitate" means that you can rip it open, find a suitable
connector, attach a pigtail of some sorts, snake it through a hole
somewhere, and attach an external antenna. I'm not sure how I assumed
that it was a G4, but I may been mistaken. PowerBook G3 also came in
12, 15, and 17 versions. Anyway, if this is wrong, I stand corrected.

--
Jeff Liebermann jeffl@cruzio.com
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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