Wireless stability when signals are TOO strong?

I read (I think in the firmware for DD-WRT) that you should never change the firmware over a wireless connection due to the "inherent instability" of a wireless connection. Fine.

I was web browsing the other day and it was acting like I had a poor WiFi connection - I was re-loading webpages, re-submitting forms, etc. Remembering the DD-WRT warning, I decided to switch to my wired connection. Sure enough, things were better.

I normally would assume this is normal but in this case the distance between my laptops high gain antennas and my WRT54G (v4) router was only 12".

Could I be overloading my radios? Both my Atheros mini PCI card and the Linksys router are set to 100mw and both have dual external high gain antennas (7dbi on the laptop and 9dbi on the router).

So, is this overload or is wireless just that unstable?


Reply to
Ken Bessler
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Maybe on yours, not on mine and thousands of others that are set up correctly. I do firmware updates via wireless.

Incorrect settings on your router.

So why have external high gain antennas to cover a distance of 12"? Usually they AC built in to stop that.

No, you just have the incorrect settings on your router as confirmed when you try and use a modem instead.

Go back to the forums and ask people about the claims they are making. They will help you.

Reply to

Why not try more separation and see if the problem goes away? Also don't use the high gain antennas.

If something goes wrong with a firmware update, unless the device has backup (like dual bios motherboards), the device can be made inoperable. This is why manufacturers emphasize doing firmware updates over wire.

Ken Bessler wrote:

Reply to

"Ken Bessler" hath wroth:

Sigh. There's nothing unstable about the wireless connection. What happens is that during the firmware upgrade process, the wireless connection is often disconnected by the running firmware. When that happens, the firmware upgrade is aborted and does not complete. This does not happen with the wired ethernet connection, which is why firmware upgrades should always be done via a wired connection.

There are some people that have mentioned that they have successfully upgraded the firmware via wireless. I've also done it successfully. However, I've also done it via wireless by accident, when I had BOTH a wired and wireless connection running from my workstation. It died near the end leaving me with a mess.

Sounds like interference from another wi-fi system on the same channel.

That's a bit close. It's been a while since I've measured the overload point on the WRT54G. I vaguely recall around -10dBm. You'll probably get that at about 1ft antenna to antenna separation.

Yes. Lets do the math and calculate the minimum range (so that I have an excuse not go do the laundry). It's exactly the same as the link calculations. See: |

formatting link
TX power = +20dBm (100mw) TX coax loss = 0 TX ant gain = 9dBi Distance = unknown RX ant gain = 7dBi RX coax loss = 0 RX sens = -84dBm (at 12Mbits/sec) Fade margin = Not needed here RX signal = -10dBm (overload point)

Plugging this mess into:

formatting link
trying various values of distance until the RX signal level is approximately -10dBm. I get a distance of 0.0012 miles or 6.3 ft. We're getting into the near field area so this number is at best a bad guess, but it should give you some idea of where the problems will start. 1 ft is much too close.

I'll see if I can find the magic number for the WRT54G overload point.

My seismograph shows no earthquake activity, so I guess it's stable.

Reply to
Jeff Liebermann

[compton ~]$ finger -l snipped-for-privacy@quake.geo.berkeley.edu [...] ****************************************************************************** DATE-(UTC)-TIME LAT LON DEP MAG Q COMMENTS yy/mm/dd hh:mm:ss deg. deg. km


06/05/05 06:36:18 38.24N 118.76W 0.0 4.7Mw C* 22 km E of Bodie, CA 06/05/05 06:39:38 38.21N 118.78W 11.4 2.2Md C* 21 km E of Bodie, CA 06/05/05 06:44:11 38.23N 118.76W 4.0 2.3Md C* 22 km E of Bodie, CA 06/05/05 09:14:31 38.21N 118.77W 11.8 2.3Md C* 21 km E of Bodie, CA 06/05/05 14:35:55 38.22N 118.77W 14.6 2.2Md B* 21 km E of Bodie, CA 06/05/06 03:51:09 37.55N 118.82W 3.1 2.2Md A* 12 km W of Toms Place, CA 06/05/06 17:28:44 38.81N 122.80W 3.4 2.5Md A* 1 km NNE of The Geysers, CA 06/05/06 18:39:54 35.72N 121.14W 4.7 2.5Md C* 9 km NNE of San Simeon, CA 06/05/06 20:36:59 36.98N 120.77W 5.5 2.1Md B* 11 km SE of Los Banos, CA 06/05/07 02:03:39 37.26N 122.13W 6.8 2.3Md B* 10 km SW of Cupertino, CA 06/05/07 02:45:32 36.03N 120.60W 7.7 2.3Md B* 21 km NW of Parkfield, CA 06/05/07 07:37:38 40.37N 124.16W 30.1 2.2Md B* 12 km ENE of Petrolia, CA 06/05/07 08:55:16 36.04N 120.61W 9.5 2.5Md A* 23 km NW of Parkfield, CA 06/05/07 13:59:42 38.22N 118.76W 13.1 3.1Ml B* 22 km E of Bodie, CA 06/05/07 14:06:40 38.20N 118.78W 5.0 2.0Md C* 20 km E of Bodie, CA 06/05/07 17:43:36 38.80N 122.80W 1.8 2.4Md A* 1 km E of The Geysers, CA 06/05/07 22:55:49 38.83N 122.80W 2.6 2.1Md A* 4 km N of The Geysers, CA [compton ~]$

Yeah, I know - Californians never notice anything less than a 5.0. ;-)

(Used to was, you could finger snipped-for-privacy@andreas.wr.usgs.gov as well, but it's not replying to me.)

Old guy

Reply to
Moe Trin

snipped-for-privacy@painkiller.example.tld (Moe Trin) hath wroth:

formatting link
much near the Peoples Republic of Santa Cruz. I guess my wireless access point is stable.

Well, we don't really get use to minor earthquakes. We just learn to pretend that the next shaker will not turn into "the big one".

Reply to
Jeff Liebermann
[POSTED TO alt.internet.wireless - REPLY ON USENET PLEASE]

It all depends on how the router is designed. It's not hard to design a device that isn't killed by an interrupted firmware load. If it is killed, that simply means that it was badly designed. Return it under warranty and get something better.

Reply to
John Navas

[two web pages]

I like the finger service - faster, as you only get about a page of text. When I was living in the Bay area, I had a shell alias ('quake') that ran finger against the UCB and Menlo Park servers.

I knew Berzerkely had declared independence decades ago - didn't realize the movement had made it to SC. I thought that this one

]06/05/07 02:03:39 37.26N 122.13W 6.8 2.3Md B* 10 km SW of Cupertino, CA

was probably the closest, but a 2.3 would be very hard to detect.

One would hope.

True story - I'm in some self service gas station on El Camino in Sunnyvale, filling up the car. You know, leaning against the car, holding the nozzle control, and looking in the direction of the pump (but with the mind a million miles away thinking about some problem at work). The car begins gently swaying, and I look around trying to see which wise-ass it is from work who's rocking the car as a joke. Then I see the woman who has the driver side door of the car in front of me open, as if she's going to get in, and her eyes are as big as dinner plates - _REAL_ panicky looking. Glance at the plates on the car - someplace back East. Look around - nobody else is even looking around. Hmmm - probably a 3.0

I was a bit further away from Loma Prieta - maybe 21 miles (just South of the junction of 101 and 237). USGS had a seismometer very close by, which showed 11 inches of movement, mainly up/down. The horizontal component was about 4 inches - at a right lively rate. I had an empty glass fall off the table, and a light switch broken (bookcase swaying sheared off the actuator of the switch). Is channel 54 still showing "Surviving the Big One" from KCET during pledge week? I think I still have a copy on tape - we must have watched that program half a dozen times - learned something each time too.

Old guy

Reply to
Moe Trin

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