Q: Should I create a separate 5ghz network or does automatic selection of 2.4 or 5 work fine?

The simplest setup....which is best for most users....is to use the default setup where both the 2.4 GHz and 5 GHz bands use the same wireless network name.

With this setting, wireless devices will automatically choose the best quality signal with which to connect based on their capabilities and distance/location in relation to the AirPort Express.

If both are available, will the device always choose the 5 over the 2.4 (if it can handle 5)?

No. 5 GHz signals are much weaker than 2.4 GHz signals, so they do not pass through walls, ceilings or other obstructions nearly as well as the stronger 2.4 GHz signals.

If you have a device that is capable of connecting to 5 GHz, it will do so if it is in close proximity....the same room or it has line-of-sight with the AirPort Express.  But, that same device will likely connect using 2.4 GHz if it is a room or two away from the AirPort Express since the 2.4 GHz signal will be much stronger than 5 GHz at that location.

If you use the option to assign a separate name to the 5 GHz network, in theory, you can "force" a device to connect to the 5 GHz band.  This might make make sense if all of your 5 GHz capable devices will be in close proximity to the AirPort Express.

But, connecting to 5 GHz is no guarantee of a better or faster signal if the device is located some distance away from the AirPort Express....where the 2.4 GHz signal might be not only stronger, but faster than the 5 GHz signal.

So, to review again....If you leave the AirPort Express in the default setup, devices will automatically connect to the band with the best signal quality based on their capabilities and distance/location in relation to the AirPort Express. Isn't that what you really want?

How do I know whether the Apple TV (or other device) is using the 5ghz or the 2.4?

Use AirPort Utility to check the connection details for each wireless device.

Hold down the option key on your Mac while you double click the AirPort Express icon in AirPort Utility. Each wireless client will be displayed. Click the arrow next to each wireless client for more connection details.

No. 5 GHz signals are much weaker than 2.4 GHz signals, so they do not pass through walls, ceilings or other obstructions nearly as well as the stronger 2.4 GHz signals.

 

This highly depends from country to country and should be taken with grain of salt.  I think that current regulations in the United States allow 5GHz WiFi equipment to transmit at sufficiently higher power levels so that the problem more or less doesn't exist anymore for 5GHz WiFi applications (provided hardware on both sides takes advantage of higher power levels allowed).  In my home, 5GHz is way faster than 2.4GHz even with several walls between AP and wireless client, and not too ideal location for the AP either.

I keep my setup of two separate networks (back from the days where I had to have two separate AP, one for each band), as my experience is that most WiFi chips are too brain damaged to pick optimal frequency band if left to pick it on their own.  Said that, after I replaced my ancient Airport Extreme (that could do only 2.4GHz or 5GHz, but not both at the same time) with much newer Airport Extreme that has full dual band support (and got rid of separate second AP for 2.4GHz band), I haven't tested if Airport would actually force clients to connect to what it thinks is optimal band for the client.  Or if it is left for the client to pick.  If latter is the case, then definitely setup separate network for 5GHz band.

Bottom line is, try both options and see what results you get and what works for you.  Your home is different from my home.  And both our homes are different from Bob's home.

I agree with the comment above. I purposely set up a separate 5Ghz network for my ATV and it works great. The AE is in a room next door high on a bookcase. The signal is great and no lag when I am on my iPhone or MB connected to the 2.4Ghz network. Test differnent settings for your needs. Sometimes the automatic default isn't the best. I am also noticing that the automatic channel selection isn't the best either. Almost every neighboring network is on channel 1 or 6 causing lots of interference.

Alex-- wrote:

 

No. 5 GHz signals are much weaker than 2.4 GHz signals, so they do not pass through walls, ceilings or other obstructions nearly as well as the stronger 2.4 GHz signals.

 

This highly depends from country to country and should be taken with grain of salt.  I think that current regulations in the United States allow 5GHz WiFi equipment to transmit at sufficiently higher power levels so that the problem more or less doesn't exist anymore for 5GHz WiFi applications (provided hardware on both sides takes advantage of higher power levels allowed).  In my home, 5GHz is way faster than 2.4GHz even with several walls between AP and wireless client, and not too ideal location for the AP either.

Most of that's wrong, the allowable tx power the is same for both frequencies. 5Ghz signals (because they are higher in frequency and obey the laws of physics) have less range than 2.4Ghz signals. On the plus side the 5Ghz band can accommodate more channels. It also tends to be less crowded.

Max speeds are defined by the protocol in use, not the RF frequency.

Sorry for what will be an elementary post. In haste I clicked the 5ghz option when setting up my new Time Capsule and named the 5ghz network. In reading more I realized I should not have done this and should have left the default settings. Is their a way to get rid of the separate 5ghz network? I have unchecked the box but the named network continues to show up in all of our devices. Any help would be much appreciated.

In each device click Settings > Wi-Fi, click on the named network (the one you wish to remove), then select 'Forget This Network'

Hope this helps.

Here's an observation, but the explanation of what I'm going to describe isn't entirely clear to me.

With my Macbook Pro Retina 15" (mid 2014) and my AppleTV, both in the same room as my Airport Extreme, it makes no difference at all whether I separate the 2.4 and 5 ghz bands and name them differently.

I also have a Sony BlueRay player and older HP All-in-One jet print scanner/printer, neither of which seems to recognize the 5 ghz band. The Sony BR freezes frequently--briefly, but still--when I have the two bands running under the same name. When I give a separate name to the 5 Ghz band, it doesn't freeze. And the HP printer doesn't connect reliably to wifi when the bands have the same name, but is much more reliable when I rename the 5 ghz band.

Admittedly these are impressions rather than scientific experiments, but I think they are valid, and I suspect that the wifi devices that don't recognize the 5 ghz band at all get "confused" when hit with both signals from a very close-by router, and effectively are experiencing network disconnects.

Whether true or not, I can't see any downside to separating the 2.4 and 5 ghz bands and naming them differently, or any particular advantage to having them have the same name..

Am I missing something here?

I'm going to have to revise my comment above--there's no way to edit it at this point.

It turns out that I had a bad Airport Extreme--2nd time this has happened with the same problem. The 2.4 ghz band started working erratically, then just stopped working altogether. After an hour on the phone with Applecare yesterday, the agreed to swap it out, which I was able to do today at an Apple Store.

With my new Airport Extreme (they say it's not refurbished, but actually new, although it didn't come with the new accessories), the 2.4 ghx channel is again working, as are my devices that see only 2.4 ghz wifi. I haven't yet gone back yet to a single name for both the 5 ghz and 2.4 ghz channels to test out the theory I advanced above. I suspect it was a hardware problem with the Airport Extreme all along.

I Wonder if the two networks are named differently, with two Apple devices like maybe an iPad and a air printer that work on the same network will still see each other if one is on the 2.4 network and the other is on the 5 network and they have different names. (Bad sentence structure). Same thing for Air drop etc. I know my air printer and iPad don't work together on our motel network because they are signed on separately.

with two Apple devices like maybe an iPad and a air printer that work on the same network will still see each other if one is on the 2.4 network and the other is on the 5 network and they have different names.

It will work fine.. apple do not isolate clients on the wireless.. so it makes no difference which the device joins.. it will receive an IP and gateway from the router and that will be same local LAN as the other.. the only time this is a problem is when wireless is isolated. eg hotel or motel networks where they do not want clients seeing each other. Or guest network on the airport which is deliberately isolated.

Csound1 wrote:

 

Alex-- wrote:

 

No. 5 GHz signals are much weaker than 2.4 GHz signals, so they do not pass through walls, ceilings or other obstructions nearly as well as the stronger 2.4 GHz signals.

 

This highly depends from country to country and should be taken with grain of salt.  I think that current regulations in the United States allow 5GHz WiFi equipment to transmit at sufficiently higher power levels so that the problem more or less doesn't exist anymore for 5GHz WiFi applications (provided hardware on both sides takes advantage of higher power levels allowed).  In my home, 5GHz is way faster than 2.4GHz even with several walls between AP and wireless client, and not too ideal location for the AP either.

Most of that's wrong, the allowable tx power the is same for both frequencies. 5Ghz signals (because they are higher in frequency and obey the laws of physics) have less range than 2.4Ghz signals. On the plus side the 5Ghz band can accommodate more channels. It also tends to be less crowded.

 

Max speeds are defined by the protocol in use, not the RF frequency.

Not really the same.  In United States, for 2.4 GHz band, it is 1W on all allowed channels (1-11); for 5 GHz band, it is 200mW for channels 36-48, 1W for channels 52-64, and 4W for channels 149-161.  These numbers are valid only in United States, regulations in different countries are different.  Cisco has handy table for what regulations look in different countries.  If you setup your router to use one of the channels in 149-161 range for 5 GHz band *and* your WiFi devices do take advantage of higher allowed power output when using those channels, it mostly negates effects of 5 GHz having less range than 2.4 GHz.

Thank you Alex, the information you provided helped to fix the inconsistent speeds I was receiving over the WiFi network. I have tried different settings on the AE, but nothing solved the issue. After reading your post, I manually set the 5GHz to 157 and 2.4 to 6 channels. Now I constantly receive the max speed which is 65MBs down and about 5 up with our provider. Befor that I had set both channels to auto and as soon as walked out from the room where the router is placed, the speeds dropped to around 30 - 35MBs.

I realize I'm replying to an old post--but there have been quite recent responses, so hopefully I can still get an answer. In his excellent reply, Bob Timmons wrote:

Use AirPort Utility to check the connection details for each wireless device.

<<Hold down the option key on your Mac while you double click the AirPort Express icon in AirPort Utility. Each wireless client will be displayed. Click the arrow next to each wireless client for more connection details.  <<

I did this, and it worked: I got more connection details, including the data rate, but I could not tell which network--2.4 or 5 GHz--each device was connected to. Here's what's included in the extra info: Connection [quality]; data rate; IP address; hardware address; RSSI, and Mode. It's possible that info is buried in there somewhere, but I can't extract it.

I'm looking for evidence that devices in different rooms are indeed connecting at different frequencies.

Thanks,

Jim

For Mac's there is an App you may be interested in.  It does identify frequency band (2.4 or 5 GHz) as well as signal strength, base station name, network name, channel, & data rate.  The data display is also dynamic in that you can move around the room/house and see changes taking place. 

You will find it in the App store named WiFi Signal, priced at $2.99.  I find it to be well worth the price.