Wifi Constantly Dropping in Lion

Quick Update:

I looked at the post above and thought, "what the heck, I'll give switching to Channel 11 a shot too" and it worked! My iPhone 4 picked up the WiFi Signal once again.

To recap my situation for those interested: Prior to 10.7.4 my iMac (September 2011) would not maintain a connection over N, either in 20 or 20/40. After Update 10.7.4 iMac maintains a connection (after 9 hours now) over 20 MHz but not 20/40. iPhone was not able to connect though, over just 20 MHz until I changed my Channel from 6 to 11.

All devices are connecting now and my iMac is getting a 130 Mbps Link Speed to the router (not a Dual Band Router) without the normal drops of connectivity every 15 minutes.

Fingers crossed. I will keep you all posted, cause I know you're just on the edge of your seats! LOL

i don't know how long it takes the connection to drop - probably after an hour or more of inactivity.

there are several macbooks here and a couple of iphones, though not everything is connected at the same time.

i have just switched to channel 11, but i think we are getting away from the cause of the problem ... everything was working fine until i updated this imac from snow leopard to lion the other day. the problem is surely something that needs fixing within the OS or its settings - not a problem with my network set up, which hasn't changed ?

mark

DrVenture wrote:

Mark,

Let's try moving your router to channel 11. There are too many people using channels 1 and 6 and the channel you are using (3) overlaps with both channels 1 and 6.

Do you have a lot of other devices connecting to your WiFi (like mobile phones and other PC/Macs)?

Do you notice if the connection loss happens at random intervals, or is it pretty consistant (e.g. every 20 minutes)?

Regardless, you should not be using a channel in between 1, 6 or 11. Especially when your neighbors are using non overlapping channels. It just bleeds noise into the neighboring channels.

While I agree this does not account as to why the iMac started to have issue after the update, it still does not mean you should not use a good channel.

Try channel 11 and see what happens.

Never, EVER EVER use HT 20/40 or just HT40 in 2.4GHz.It consumes too much bandwidth in an already bandwidth constrained frequency. Rememer, you are contending with neighboring routers in 2.4GHz, Bluetooth devices, etc. Besides, Macs will not use HT 40 in 2.4 just for this reason (Apple blocks it).

If you want high throughput with wide channels, get yourself a nice simultaneous dual band router and off wide channels on 5GHz.

Good to know. But why would Apple do this for iMacs only and not their other platforms (i.e. iPad and iPhone)? I also think its kinda dumb for the Router to give the option if all it does is cause problems (at least with iMacs).

Update: No drops yet! 10.7.4 is still working 😉

No Apple device, Mac OS X or iOS will do HT 40 in 2.4GHz.

Routers do it so they can advertise on the outside of thier box that they do high data rates. It called keeping up with the Joneses at the expense of the Smiths.

Glad to hear things are better for you.

i have just switched to channel 11, but i think we are getting away from the cause of the problem ... everything was working fine until i updated this imac from snow leopard to lion the other day. the problem is surely something that needs fixing within the OS or its settings - not a problem with my network set up, which hasn't changed ?

Practically, you can say this over and over, and think like this, day in and day out. But, in reality, you never know when your neighbors have increased their WiFi use. They may have bought an Apple-TV, and started streaming netflix on it, on the same day you upgraded to Lion. That could of saturated channel 1, and made it very difficult for things to work.

What I would suspect, more than anything, is people are, in fact being bombarded with all kinds of new WiFi traffic, as people buy and start using all these smart devices. On 2.4ghz, anything more than a handful of devices on a single channel, is going to be problematic. There is just too much stuff on 2.4ghz with all the wireless phones (not cell phones) , bluetooth, wireless TV extenders/relays etc. If you are in an area with the kind of 2.4ghz traffic visible in your "airport -s" output, then you really need think about moving to 5ghz.

You can stand around and blame Apple, still, but there will be less and less that they can actually do to fix the problem for you. RF is RF, and there are properties of receivers that just can't be "altered" to deal with more interference with the type of "emissions" that 2.4ghz b/g/n are using. B is clearly terrible for bandwidth, but is "narrow" which means more power is going into delivering that small slice of RF. G is wider, and thus doesn't go as far with the same power out. N is even wider, and thus much shorter ranged. A B signal on channel 1, can competely destroy G and N sessions on channel 1, if it is too close, because it will be stronger.

In the output of airport -s, you will see the signal strength in the form of the negative numbers. Anytime you are trying to find a better place to be, look at these two values in the output of airport -l.

agrCtlRSSI: -40

agrCtlNoise: -96

The first is how "loud" your router is to the computer. The second is the noise floor. The noise floor is pretty quiet, so there is nothing close, screaming out. The compare the first value to the RSSI in the airport -s output.

Look at how many people are on your channel, and also the signal levels. Anything about -70 is really quite loud, well at least loud enough to be able to interfere.

If you look around at university campuses and other large areas where they try to create wireless networks for everyone to use, they refuse to let you put up a radio yourself, because if everyone was doing that in such a small space with such a large number of people, WiFi would be useless.

If you go to places which advertise wireless networks available, and they work really poorly, look around to see how many people there are there with cell phones or iPads or computers which might be trying to use the network.

It just doesn't scale with more than a handful of devices on any particular frequency. This is why cellphone networks have very low power cells by the 10s, if not 100s in large cities with huge populations. The cell phones have remote control power level adjustments that the cell sites tell them to make so that the phone's emissions can be confined to just the cell or two it is near.

Sure, it seems there was a "reconnect/retry" bug in Lion. Some people were experiencing problems, others were not. I contend, that most likely, people with very heavy WiFi or other 2.4ghz traffic around them, or who had interferring traffic on the 5ghz channel they were using, were the ones impacted by this. The radios were resetting the connection, and starting over, and when they told the OS that the network was down, it wasn't reconnecting correctly.

Now that the "reconnecting" is happening "better", in that perhaps this fix make sure it reconnects very quickly with your wireless router, you might still see problems, because the environment around you is very noisy and problematic for your router, or your WiFi radio in your device(s).

gphonei rmade some good points. I would just like to mention a few things myself:

• I got drop out when my MBP 4 feet from my WiFi Base station
• I selected a channel that was not congested
• This thread has been viewed over 200,000 times, is currently 118 pages long with over 1,700 replies. I think that if these statistics don't tell you that many people are seriously impacted by this and it is not not just a few people with WiFi interference, then nothing will. You must be a member of the Flat Earth Society.

gphonei makes valid points but they were not the cause of my drops since I did exactly that when I first had the problem. I went through every channel on my router having only the iMac connected and on every channel the connection dropped. I don't have a whole lot people in my area using WiFi that I can see. I live in a small apartment so I get good strength throughout. Most of my neighbors are old folks 😐.

Then we have the issue of these Macs being the sole device being affected. If there were interference issues on that level I would expect dropping on different devices too. Changing the Channel did not solve my iMac disconnect issue, but it did help me troubleshoot my iPhone 4 not wanting to connect at all (other forums are filled with iPhones not connecting on lower channels for some reason too, and it is only the iphones that do this).

What I know is that 10.7.4 has fixed the dropouts on my iMac (still no drops! been about 14 hours now) so I am a happy camper once again. I think Channels are not the root cause, but I do think they can be part of the problem.

gphonei wrote:

But, in reality, you never know when your neighbors have increased their WiFi use. They may have bought an Apple-TV, and started streaming netflix on it, on the same day you upgraded to Lion.

Your logic is highly suspect. We are not talking about an occasional issue that began around the same time Lion was installed. We are talking about a frequent, observable phenomena, that began at the exact same time Lion was installed.

The idea that new wireless interference happened to enter an otherwise static environment at that exact moment is not the most logical conclusion, it would be a coincidence. Maybe 1 in 1000 people having this issue can attribute their problems to such a coincidence, but I doubt the number is even that high.

Then of course there is the fact that in almost all of these complaints, the computers with Lion installed are the only ones having the problem, while other devices, including 10.6 Macs and those same computers running Windows through Boot Camp, have no issues.

Oh, and Apple has released multiple fixes to explicitly address this issue. So there's that.

My question is this: Why do you go to such illogical lengths to defend this percieved slight against a faceless corporation? The wireless implementation in a complex OS overhaul was flawed. Big whoop. Who cares.

And for those of you who are still having this problem, you have two options:

A) If you are a computer novice:

- install all updates

- reset your router to its factory settings

- go into system preferences and reset every wireless preference there is

- repair your disk permissions

- reset your PRAM

That's the easy stuff. If that doesn't work, there is one more thing:

- Take it to a Genius. Keep taking it in until it is fixed or replaced.

B) If you are a bit more adventerous:

- Google.

This forum and the larger internet have a ton of possible solutions. Most are pretty complicated, some are less so. As near as I can tell the success rate here is not great. So expect to put a lot of time in and don't expect guaranteed results. For whatever reason this is a problem that appears to vary wildly from person to person.

When I first started attacking this problem my iMac only dropped when waking from sleep or logging in, but it required me to log into my wifi network every single time. Eventually one solution did fix that, but then it just dropped randomly every 20 minutes or so (without requiring a log-in). Dozens of solutions tried later and my iMac only drops every few days, though when it does it will usually drop over and over again and be unusable for about an hour. That's all I have to show for hours and hours and hours of my time and an OS whose innards probably look like Frankenstein's monster after all the **** I put it through.

My recomendation: Go with option A.

Now that my Wifi is staying connected, a new issue I was having was not being able to wake my iMac over my LAN using my iPhone/iPad using the Remoter VNC App and Sending Wake Up Packet. This has been an issue before, but I chalked it up to the previous issue of the iMac losing the connection altogether. Then I came across this in another forum:

namuh wrote:

I have an imac with Lion 10.7.3 and a linksys (cisco) router. I wanted to access it when it was sleeping, but couldn't by wifi, even though the wake on lan option was set.

After reading a bit about the problem and the various fixes, I was searching in the /Library/Preferences/SystemConfiguration folder and I saw the com.apple.PowerManagement.plist file. I opened it in an editor, and then noticed a line that had a key of PrioritizeNetworkReachabilityOverSleep.

The value was 0, so I changed it to 1 and saved the file.

Now I have no trouble accessing the Mac by my iphone, even after it sits overnight. You may want to try it.

/Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist

I did what he did and it worked! This definitely goes into the category of Apple messing up since the proof is in the Coding. I hope this helps anyone else having the issue. I figured I'd post this, since although not completely on topic, having this issue happen could hinder your troubleshooting of the primary issue 😉.

My question is this: Why do you go to such illogical lengths to defend this percieved slight against a faceless corporation? The wireless implementation in a complex OS overhaul was flawed. Big whoop. Who cares.

I'm not trying to say that the original problem was not a problem. I'm trying to say that as Apple has fixed various problems, people have continued to have "a problem", and said that Apple hasn't fixed things yet. I was trying to add to the fact that Mark's problem was solved by changing channels, to some degree. People still need to pay attention to the RF issues even as Apple fixes software problems. I have new hardware in my family, and we haven't had problems with Lion running on 4 different Macs. So, I contend that there are problems with the environment which is stimulating the broken software to be visible, that's all. Once the broken software is fixed so that reconnects/recovery from wireless failures are happening "correctly", your environment may still be impacted by being on an overcrowded channel.

The problem is also, many people do not know how to set up their wireless routers -

Unlike the Apple routers, that could be set up wirelessly and effortlessly, Most other routers need to be initially connected by an eithernet cable directly to the computer when initially setting up your primary router or repeater.

And sometimes the routers need some tweaking because let's face it updating the firmware and port numbers on some routers are quite tedious, especially if the router is more than 2 years old.

http://ww.videos-maritimes.com/video-Pw8qaomfcTg

gphonei wrote:

I have new hardware in my family, and we haven't had problems with Lion running on 4 different Macs. So, I contend that there are problems with the environment which is stimulating the broken software to be visible, that's all.

Ah. Now that is likely a correct assertion. Mostly at any rate. Obviously most users are not having pesistent issues. We know that much. There are no official numbers, but I would guess the number is high (thousands?), but not high enough to really put egg on Apple's face. The key factor is that the issue varies a lot from user to user. That generally indicates an upgrade or overhaul at a very deep level in software. You saw this sort of problem with Vista, when suddenly tons of pieces of hardware needed new drivers, many of which didn't exist.

So Apple overhauled the way Lion handles wireless somehow for some reason (probably a good reason), and it doesn't play nice with certain pieces of hardware that don't quite know how to handle it. Atheros chips seem to be having lot of trouble for example.

Another example, my iMac only has issues with my (old) Airport express. My friend's generic router works fine.

Atheros + Snow Leopard + Airport Express == GOOD

Non-Atheros + Lion + Airport Express == GOOD

Atheros + Lion + Lynksys == GOOD

Atheros + Lion + Airport Express == BAD

Something in that last combo doesn't work well with the new way Lion handles wireless.

Of course, I don't really give a ****, I just want a computer that works. I would have never upgraded the OS if I knew I what was in store for me.