Any RF engineers on here? Take a look at this - What is causing the interference?
 

Long and short of it is I purchased the new Dell XPS 15 laptop, however everyone is getting terrible wifi issues. The antennas work fine when outside the case, so something inside is the issue. Could anyone make some suggestions on what could be done to troubleshoot? The guy with the pics is having another engineer visit tmoz.

http://forum.notebookreview.com/dell...ml#post8756263

http://www.budgetlight.nl/pics/foto2.JPG

Sounds like it is shorting somewhere with the case. Just give the antenna a lookover (pref with a bright light and magnify glass) if it isnt puntured and or has a slice in the isolation.

Cheers, I would wager it is not punctured or has a slice as all owners are suffering the same issue? How would one determine where the short is?

Yeah, a quick google and it looks as though this is a very common problem. Is the case pressing on to one of the contacts or is it a heat problem? I read one of the forums someone said the problem only happened when they were on battery power, not plugged in?

oh, i thought you meant everyone who tried the laptop :D not a whole bunch of them.
as for the short, by eye. since you cant measure it when its closed.

Worst case the closure it the culprit creating a Faraday cage

It seems to be a casing issue, as heat while and issue on it's own does not affect it. Running on battery makes a bit worse as it uses less power. Nonetheless it is a terrible oversight by Dell, I bought it knowing of the issue but thinking it would be fixed via a software update. However a quick test with an Ubuntu cd and another card resulted in the same issues proving it had to be hardware.

I have kept holding off getting a MPB, as I felt they were overpriced. Plus I like the windows operating system more. However if this does not get resolved soon, then it may be the route I choose.

I know it doesn't mean much coming from the converted, but I have never regretted getting my MBP. Best machine I have ever owned.

Yeah, well ironically I got myself an iPhone after swearing not to get one. Before I did that, I was constantly changing phones all the time..Wondering if this could be the same with the MBP. I am just concerned about losing the use of a native windows pc, especially with Windows 8 around the corner.

Also how hot do they get? I keep reading the fan ramps a lot and they are too hot to use on the lap?

try fitting a ferrite RF choke to the antennae, all you need do is go out and buy a small ferrite choke donut and pass the antennae through the choke so that it loops around the ring on the way through.

that should sort things out, also see if the 40 MHz intolerance mode (fat channel) is enabled in the driver setting.

also see if the roaming aggressiveness setting is set to low, so it don't keep trying to search for stronger signals.

and play around with the send and receive signal settings.

mines set to max which enables maximum coverage

or place a piece of electrical tape over the main and aux inputs on the card if you suspect it grounding out on the casing.

It varies... the 'tock' models run hot, the 'tick' models don't. So the latest one is pretty good, my MBP mid-2010 is also pretty good. But early 2011 models ran hot.

Obviously if you game they get warm, but not as bad as some people make out. OS X is a decent power manager IMO.

This is a common problem with metal-chassis devices and it's difficult to design around. It's why portable devices that are made of metal often have plastic strips or slots near their edges. My Dell Latitude and older ASUS U-series laptops both have them. Various iPods and iPhones have them. Various tablets have them. My old Nokia N8 had them.

There's nothing you're going to be able to do about this as an end user except to use an external WiFi adapter instead of the internal one. The chassis itself is attenuating the signal.

X2. I primarily use win7 via bootcamp, it's a great combination.

I had an AT&T tech use my laptop, he had to copy some files off a USB drive and send some emails. He moved the mouse around for awhile, then looked up at me and said he didn't know how to use a Mac. I told him, its windows 7. He said "Oh" and then did what he needed to do.

Honestly though, if you can afford it, a MBP is the way to go. I don't miss my old asus laptop.


Strange issue with the Dell. If its anything like dells past, they will blow it off for a few years before they admit fault. Some of their models are great and usually what I recommend for most, but they do create some lemons.

Gonna pass this information to the thread, thanks!

Well gonna have a look today. I might buy one, and then request a refund for the Dell.

On that basis, how does Apple solve the issue of attenuation?

Through careful design and test, I would guess. In a device as large as a laptop, it's not an insurmountable problem.

I have no doubt that both of these computers have their antennas in the same type of plastic hinge section where the lid and base are joined. Dell might employ slightly different hinge geometry that interferes with reception or maybe they use slightly different materials. Who knows.

My best guess would be it's something to do with the top cover behind the LCD panel.

I'd remove the LCD, put back together as much as possible, connect to external display and try it. Maybe it's grounding on the LCD.

You should not spend a second disassembling or physically tinkering with any brand new, under-warranty, expensive top-end device. To be perfectly honest, I would send it back to Dell, get my money back and buy an ASUS or something.

This is likely a problem that's inherent to the design.

Agreed, as soon as it's opened the warranty/guarantee is usually void and you're stuck with the thing.
However, if you don't mind that and just want to find out what the issue is, then go for it.

I was under the impression some devices with metal framework use the frame as an ariel - could this be one with a bad connection or am I in error about the whole chassis/ariel concept?

yeah actually what he could do is ground the two wires to the inside of the chassis, that way the rear of the panel would act as one huge directional aerial.

Might affect battery life quite a bit. What do you think the impedance of a short across the chassis would be?

Gordo designs chassis, he can tell you. He also designs communications chips and invented WiFi. He's handy to have around.