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Mac Mini Airport Sporadic Reception

I've been dealing with the same issues for 2 months and 4 visits to the apple store. The problem is basically the same but slightly different than other posts on the same subject. I set up the Intel Mini in our room and once the high speed was hooked up to the house - fired up the base station extreme. I searched for the network and it refused to show up in the menu bar, however the Linksys from our neighbor across the street shows up quite well. I turned the airport off and back on several times until the base station shows up. I select the base station network and nothing happens. Not even an error dialogue. So I went back up to the Airport menu bar and the network disappears.

The base station is approximately 21' away in a wide open room configuration. I went to the next step and placed an airport express in the same room w/in 5' of the mini, set up to continue the base station network, and still nothing appears in the menu bar except the Linksys.

On the first visit to Apple they replaced the Airport Card. I took the mini home, same problem. I returned it to the store, I received a message that the computer works fine but I needed to bring in the base station for diagnostics.

I received a call this morning to tell me I could pick up both items, they are normal and working fine.

In the meantime, I've shared with the technicians that I have already reinstalled the software, updated any software or firmware for the mini and base station as well as repair any permissions and checked disk.

Also - I have a backup Mini PPC that I can use when the Intel is in the shop. I swapped units and the PPC mini works flawless. For the heck of it, I took my wife's MacBook into the same room, at the same location AND covered it with a cardboard box with a peep hole and still it picked up the signal with no fluctuation. Just for grins and giggles, I did the same thing with my Powerbook G4 with the same positive results.

Everything works except the Intel Mini. So I'm preparing myself to go pick up the Intel Mini, bring it home to try it again with the same results and ponder what the computer would look like as a planter because that's about what it is good for if it doesn't work.

Any ideas as to what my next step could be. As a last ditch effort, could I run an ethernet cable from my Airport Express to the mini and hopefully pick up an Ethernet signal.

Any thoughts or Ideas would be graciously accepted.

PowerBook G4; Mac Mini PPC; Mac Mini Intel: MacBook, Mac OS X (10.4.4)

Posted on Jan 8, 2008 6:49 AM

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Posted on Jan 8, 2008 7:14 AM

In term of speed and reliability, wired ethernet is ALWAYS preferable to wireless -- so I would certainly consider that before relegating the Mini to "planter" status.

Unless the Apple store is pulling your chain with the reports of both your units testing fine, I think we have to seriously consider that there is some source of RF interference in your room.

What other wireless devices do you have nearby: cordless phones, baby monitors, wireless thermometers, bluetooth phone, headset, keyboard, etc?

(BTW thank you for posting this in a fresh thread with all the information laid out in a coherent fashion. Others might learn from this example ... )

Another measure I would try would be to set the airport base station to a radically different channel, and see if that helps. It may currently be set too close to the channel the neighbor's Linksys is using. You need to be at least 3 channel numbers apart to avoid all interference.
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Jan 8, 2008 7:14 AM in response to Mark Gaipo

In term of speed and reliability, wired ethernet is ALWAYS preferable to wireless -- so I would certainly consider that before relegating the Mini to "planter" status.

Unless the Apple store is pulling your chain with the reports of both your units testing fine, I think we have to seriously consider that there is some source of RF interference in your room.

What other wireless devices do you have nearby: cordless phones, baby monitors, wireless thermometers, bluetooth phone, headset, keyboard, etc?

(BTW thank you for posting this in a fresh thread with all the information laid out in a coherent fashion. Others might learn from this example ... )

Another measure I would try would be to set the airport base station to a radically different channel, and see if that helps. It may currently be set too close to the channel the neighbor's Linksys is using. You need to be at least 3 channel numbers apart to avoid all interference.

Jan 8, 2008 7:17 AM in response to Mark Gaipo

I saw your post describing this yesterday in one of the other airport threads, and have been pondering possible responses, given the nature of the problem you describe.

The first thing to say is possibly the least relevant:
I took my wife's MacBook into the same room, at the same location AND covered it with a cardboard box with a peep hole and still it picked up the signal with no fluctuation. Just for grins and giggles, I did the same thing with my Powerbook G4 with the same positive results.

Not sure what this experiment was to try and discover, but cardboard is not the sort of material that would have any real influence on wifi signal. At 2.4GHz, radio transmissions travel effectively through such materials as if they were not there. Indeed, it requires material far more dense, and generally more likely to reflect the signal (such as metallic ductwork) or absorb it (such as the human body).

Despite that, the test with MacBook and G4 laptop picking up the wifi signal is valid in the sense that it demonstrates a usable wifi signal in the same general location the mini appears not to work. That isn't to say, however, that the signal is strong enough to overcome the mini's relative lack of sensitivity, and because of that I would suggest you experiment a little further, this time using the software I mentioned in the other thread - AP Grapher. Install that on both mini and one of the laptops. Using the laptop where you know the network is detected, check the signal strength and quality. Next, with the mini in as close to the same location as the laptop was, run AP Grapher and see whether or not it registers the signal. Likely it will, but if the noise level is notably high, the system will not offer it since it's not usable. If that is the case, you may have sources of interference in the area to which the mini is more sensitive than the laptop. That interference may not be within the building, let alone the room, and certainly does not need to be in the line between base station and system, so moving the mini and base station around may give you some idea as to whether there are better locations for either or both.

If the wifi network doesn't show in AP Grapher at all, then you have an issue with the mini, either in MacOS where it is perhaps not running the correct kernel extensions, or, most likely, the physical hardware such as antenna itself, or the connection of antenna to card. The Apple store or service provider you took the systems to really can't test the viability of the system and base station for use in your location, only that they are working and connect on the bench - perhaps with little space between, and almost certainly without any of the same potential sources of interference.

Without knowing for sure how old your mini is, I would have to say that in this situation I'd be inclined to think that Apple should be asked to repair it under warranty if it is less than a year old, based not on their testing of it, but your complaint that it doesn't connect using Airport, when in reality it should. I would have to say however that while a range of 21 feet is not great, you would actually be better off, I suspect, hard wiring the system to your router and thus using ethernet. It's double the maximum theoretical speed of 802.11g wifi, and in practical terms if there is interference present, your wifi speed even when connected could we well below maximum theoretical level.

Jan 8, 2008 9:19 AM in response to Boece

Great Feedback to all - thank you. I'm actually logged in at the Apple Retail Store now. I just discussed the issue with the technician who worked on both units. He pinged the base station for 45 minutes with no problem. During the course of discussion however I did come up with 2 more steps I will take.

1. I have been so focused on eliminating direct connected peripherals that I never focused on Network connections. When I get home I will need to disconnect my wife's macbook from the network as well as the Apple Television. If I disconnect all other devices from the network and the Intel Mini works, we can narrow it down further.

2. I have a new in box base station at work (our IT department) that I will try if step 1 doesn't work.

3. I will also follow up on the IP addresses also.

Feedback to follow.

Mark

Jan 9, 2008 6:25 AM in response to Mark Gaipo

Update 1/9/08:

Plugged Airport Extreme back into network - confirmed function with Macbook, Apple TV and PPC Mini. Then powered down MacBook, Apple TV and PPC Mini. Swapped out Intel Mini with PPC Mini - eliminated all hard wired peripherals and network connections. Powered down adjacent printers (older models, not bluetooth or wireless).

Same Problem - Intel Mini will intermittently show Home Network and neighbors linksys. Downloaded AP Grapher to Macbook, burned CD and installed on Intel Mini. I took snapshots of the graphs and readings and I can post them to my shared iDisk Folder if anyone is interested in working this through further.

I noticed that the Apple Techs had created a new Port for the Airport (AirportII) so I created a new port again (Airport*) and deleted previous port - still no change.

Tonight I will bring my G4 Power Book and MacBook into the same room on the same desk all with Aiport menu bar open and take a digital picture to show that all computers but the Intel Mini is receiving the signal in the exact same location.

Does Apple have an process to resolve mattes such as this, that are still unresolved?

Thanks Again.

Jan 9, 2008 6:43 AM in response to Mark Gaipo

Does Apple have an process to resolve mattes such as this, that are still unresolved?


Assuming you are still in warranty cover, then yes, they do. You need only keep talking to them, either at the store or by phone, describing the problem and reporting 'progress' in terms of testing done, or simply ask that the system be repaired. They understand that there are problems reaching an absolute diagnosis on the test bench, but that if other systems connect and the mini doesn't, there must be something significantly wrong. Ultimately, they want to see this resolved and will resolve it, even though you may need to send the system back to Apple to achieve that.

I'm interested in the comparative AP Grapher results as I described in a post above, simply because these results will indicate to what degree the mini 'sees' the wifi networks differently. As such, when you have a comparative shot from one of the wifi-viable systems such as the PPC mini or MacBook and one from the Intel mini showing your home network as visible, I'd be very interested in seeing it. That would illuminate the issue somewhat. On balance at this moment, I'd say it was likely the hardware in the intel mini is the problem - likely antenna connection as the prime suspect, but the AP Grapher results would help confirm (or refute) that.

Jan 9, 2008 7:02 AM in response to Mark Gaipo

After you follow up on Andy's suggestions, I'd still check out a channel number change on the airport unit.

Andy's probably right about the Intel Mini's antenna, but it is odd that you pick up the Linksys so easily from across the street. So it might be worth checking that your airport base station is at least 3 channel numbers different from that Linksys.

(And of course it's possible that a different neighbor's access point is interfering, but you don't know it because they aren't advertising the AP's name.)

Jan 9, 2008 7:17 AM in response to Boece

(And of course it's possible that a different neighbor's access point is interfering, but you don't know it because they aren't advertising the AP's name.)


In AP Grapher, you would typically see such a thing as a raised Noise, lowered SNR (signal to noise) or lowered comm quality trace, where often it would vary with small movements of the actual system.

but it is odd that you pick up the Linksys so easily from across the street.


having experienced the difference in signal between an Apple base station and Belkin unit, and having a neighbor across the street who has a linksys which despite the range shows up on my systems pretty strongly, I am not sure this is unusual. It might be that the linksys is an 11b WAP for example, which typically have better range, or the Airport base is not set to full operating power.

Even so, the results should be broadly consistent across each of the tested systems, and the fact they appear not to be from the description is what points at this stage to the mini's hardware as the primary suspect.

Jan 9, 2008 8:11 AM in response to AndyO

I've posted the snapshots from last night and this morning.

http://homepage.mac.com/markgaipo/

The shots are pretty easy to follow. The network is KUDRO

On one shot, Kudro shows up on AP Grapher but not menu bar. On the next shot you will see (2) networks named Kudro - the network with a 6% is actually an airport express I bridged and is sitting approximately 10' from the Intel Mini.

I will obtain grapher readings from the remaining computers tonight to compare.

Jan 9, 2008 9:10 AM in response to Mark Gaipo

Interesting. I take it that picture 5.jpg is off your Intel mini? The signal and noise levels look rather low, and the 12/54Mbit figure tends to suggest the signal is rather poor quality - added to that, the comm quality trace is quite variable, which could account for disconnections. It would have helped to have the SNR trace on that graph too though to give a more complete picture. Also to have a comparative shot of the same network off one of the other systems which connect and remain connected to the same network. I look forward to that when you've had the chance to take the pictures and upload them. By the way, best switch all the traces on in Ap Grapher to give the widest range of information!

Incidentally, AP Grapher will show any detected network, while the ones offered in the Airport menu are those with characteristics which make them viable to connect to - thus you will often see more networks in AP Grapher than the menu bar.

Jan 9, 2008 5:05 PM in response to Mark Gaipo

I've sort of been dealing with a similar problem, but I was blaming Comcast for slow service. (I still can't explain why download speed would be decreased by 50% and upload speeds unaffected.) I have discovered that our Mini/Airport network works better with the Mini tilted on its side, with the Top of the Mini and antenna facing the airport. Have you been trying different orientations of your mini facing the airport? What about orientations of the Airport?

Question: If the Airport is sitting level on a shelf, and the mini is horizontal and level on a shelf, is it better for the radio reception to have the mini and the airport at different heights and not level with each other? In my house, both are close to the same height but 30 ft and 5 walls apart.

Jan 10, 2008 4:05 AM in response to John Hess1

Question: If the Airport is sitting level on a shelf, and the mini is horizontal and level on a shelf, is it better for the radio reception to have the mini and the airport at different heights and not level with each other? In my house, both are close to the same height but 30 ft and 5 walls apart.


Not necessarily. Wifi networks are nothing more or less than radio transmissions, and as such they are affected by all the same things. To say the two devices ought to be at different levels would imply that the casing of the mini is relatively impervious to radio signals, but in reality that is not really so because it is not a Faraday cage. Signal can, and does, pass through the structure of the system, though there is certainly some attenuation. Changing the angle of the mini, or the angle relative to the base station has potential to change a number of characteristics of signal, such as reflection, deflection, absorption, attenuation, relative interference etc. The impact of these changes varies from situation to situation so it's not predictable, but at these frequencies and transmission power levels, very small variances in location, RF (radio frequency) noise, multipath distortion, co-channel interference, harmonic interference etc, can have a dramatic impact on quality of connection.

As such, it's not the structures between the transmitting and receiving antenna that are all that important. Signal will pass through walls with barely any attenuation. Distance is the most critical factor since power levels in the 11b and g standards are designed to provide for very specific signal range. Reflective materials such as metal ductwork or ferroconcrete will create multipath distortion which can give the impression of good signal, but actually result in very poor connectivity (in FM radio, this is often described as 'the birdies'). Absorptive materials (such as the human body) can result in signal fading as the materials move, and interfering materials (other electronics such as a TV for example) can create RF noise which as it increases actually swamps the actual signal.

These are really all the same sort of issues radio and TV stations employ extensive engineering teams to deal with, and which the FCC (other licensing and regulatory bodies in other countries) wrestle with when granting licenses and managing the radio spectrum - it's therefore no wonder that many people have curious wifi issues in their homes!

Jan 10, 2008 10:04 AM in response to AndyO

Andy, I got caught up in another project last night at the house. I hope to have all new readings to review this evening or tomorrow morning. I am still learning the user interface of AP Grapher and have taken your suggestions. I will put the snapshots into separate folders for each computer and there will be graphs for each network.

Interesting Point - I too am on Comcast and had initial concerns about the source but I keep coming back to the fact the PPC Mini in the same location works Flawless.

Regarding tilting and angles, picture this, I went as far as to wrap an old metal cloths hangar around my Intel Mini to increase reception too, but it obviously had no effect, other than the comic relief of those who may read of my antics.

Mark

Mac Mini Airport Sporadic Reception

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