NetEffects

Background:
I’ve had this internet sharing network up and running flawless for 4 months. I have an 8dbi omni on my chimney and two users with 8dbi patch directional antennas under eves. User 1 is north about 1100 feet and user 2 is west about 900 feet away. This is in a very rural area with only about 7 houses in sight.

I am using Dlink 900AP+ units, and at install got -65dB for user 1 and -61dB for user 2. Both great levels since the unit have a -79dB sensitivity. These readings were taken with NetStumbler and both had noise levels of -95dB or lower.

Problem:
Last week user two had a slow connection that dropped out often. User 1 had no disconnects. Pinging user 2 returned some pings along with some timeouts. I checked user 2’s signal at the AP connection and at the antenna and found it to be -75dB. I replaced the antenna re-aimed and only could achieve -73dB with a noise level of -95dB. After that I changed the AP channel and the levels came back to the -62dB range.

A couple days later, this channel showed problems, so I again changed channels which resolved the problem. It acts like a cordless phone is changing channels and blocking the signal. However, they don’t have a cordless phone, and I asked their neighbors if they got anything new or moved anything, nope.

Questions:
Could this still be interference even though NS reports low noise levels? Would a device like a cordless phone ‘lower’ the AP level NS is seeing, or should it only show up as noise? Is there any other way to find a rogue signal? Any other ideas on what to look for? I don’t know what else to do but change channels every other day.

streaker69

Check all your connections for weather wear. It's possible water has penetrated into the Coax and could be causing an intermittant short. Snow and ice can cause connections to expand and contract in strange ways and force what seem like good connections to go bad.

As for rogue signals, NS will detect if there are any other AP's in the area, but as for cordless phones, you'd need some other rather expensive equipment to detect them.

If none of this works, look for Black Army helicoptors hovering nearby, could also be aliens, sunspots or quantum interferance.

I heard that cattle mutilations were on the rise in your area.

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NetEffects

Thanks for the response!
Weather was my first thought. I tested the signal right at the antenna (pig tail) and got the same reading. So, I swapped the antenna, still same reading. Then, changed channels without moving any cables and it went from -73dB to -62dB. Switched back, still -73dB, so I changed it back again to the new channel and left it. I knew it could be back again, and it did show up. So that’s what I have been doing, changing channels to keep the connection alive while I try to find what is following me around.
Channel History
11 (5 months no problems)
6 (one day okay, then same problem)
3 (two days, then same problem)
1 (currently on this channel, no problems yet)

Haven't looked into the Helicopters, but I will check the neighbors cow inventory tonight when I get home!

streaker69

Your antenna's aren't iced over are they? Are there any trees that are in the periphery of the LOS that are iced over and causing a signal refraction? Try to think back to when the problem started and the weather conditions at the time?

It's also possible that your AP is just taking a dump.

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NetEffects

No Ice - When I replaced the antenna it was room temp and still gave the same signal until I changed channels
Interesting thought with the trees, but no. It does it when it is -10 at night or 40 during the day.
Replaced the AP with a spare, same problems.

Why do you think the signal strength is great when I move the channel? Do cordless phones and other electronics cover all the channels 1-11, or are some better than others?

Thanks again.

streaker69

2.4ghz cordless phones use the same channels as 802.11 wireless. I only notice a problem in my place when the phone is offhook. So unless someone has one offhook all the time in your area, that shouldn't be it. If you roam around the area with NS running, do you find any other AP's? Have you tried it with all your own wireless PC's in your place turned off? Maybe you have a bad nic that's just broadcasting constantly.

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nashr

I don't see any mention in your post. Are there any other APs in the area? Perhaps running on channels that could cause interference?

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rjdenver

So does this never resolve itself over time? Do you always have to change the channel for the improvement? Or have you tried waiting 24 hours once you notice the problem to see if it improves? It does sound mostly likely there is some other AP or phone that is occasionally getting a conflict.

RjDenver

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NetEffects

My house is all hard wired, and so are the two other clients. I might just take one of my directionals and start sweeping that area. I would be surprised if anyone around there had a wireless network since I am the only one with broadband (Via 5.8Ghz wireless) and everyone else is on 26.4 dial up. Maybe it's a house on the other side of the woods. One neighbor had a wireless intercom (2xx Khz I believe) I had them unplug it with no real difference.

NetEffects

Sometimes the signal does resolve itself. In some cases I have switched back to a channel that was completely blocked before, and now runs fine. That's what led me to believe I had ice/snow/water in a connection, but completely disproved that. I also thought it might be weather related and was charting temperature versus AP disconnects, but that didn't show any relationship. It may be on some type of schedule, but I can't figure it out. It appears more like something hops on that frequency, stays for x hours, then moves or shuts off for y hours, then shows up on a different frequency. That's why I thought it was a cordless phone, but I can't find one anywhere.
If it is an AP, wouldn't the user have to be changing channels? Does anyone make an AP that automatically changes channels?
That household did cancel their land line telephone service. I wonder if they stuck their cordless phone in a closet and the handset is changing channels looking for the base? Would the phone rapidly search through channels or slowly?

NetEffects

Just thought I would do a follow up. Looks like after a week of no problems we have a winner. The owner of the house cancelled land line phone service since they have cell phones and broadband through the share. They had three cordless phones that never gave any problems, until, they unplugged them and stored them away. Two in the house and one in the pole building.
I had them remove the batteries from the hand sets since they were not using them. Since then, no problems at all.
I would guess the phones were searching for the base, which was no longer powered up. I still am surprised with a directional antenna that a phone could lower the signal so much. I am also surprised we never had problems before with the phones. Apparently they 'skipped' the channel the WiFi was on for a 'better' channel.
Thanks to everyone who helped with this problem.

streaker69

That's ok, just send a check to the following address to support the upcoming StumblerCON.

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