2.4GHz Versus 5GHz Wireless

Discussion in 'Mac Accessories' started by MagnusVonMagnum, Nov 7, 2010.

  1. MagnusVonMagnum macrumors 601

    MagnusVonMagnum

    Joined:
    Jun 18, 2007
    #1
    I now own a Netgear Dual-Band model that can do both 2.4GHz and 5GHz networks simultaneously. So many articles talk about how fantastic 5GHz is for maintaining fast wireless connections due to so many non-overlapping channels enabling channel bonding without interference. In fact, I have many neighbors with 802.11G networks to interfere on the 2.4GHz band but NONE with a 5GHz network in range. Great, I should be clearing 300Mbps easy right? Wrong.

    The one thing many articles fail to mention about the 5GHz band is that it has terrible difficulty penetrating solid objects, namely walls. Thus, the problem of interference is moot if you cannot get a solid signal in a room where you need it. For example, I have a bi-level style house that isn't terribly huge (~2000 Sq. feet with the bottom floor included) and it has a fair number of rooms, which is to say it's not an open floor plan like some ranches in places like Arizona typically offer. Net Tumbler will report a 42-48% signal on the opposite side of the house on the lower floor (it's not really possible to put the router in the center of the house and some tests showed very little difference there anyway, possibly due to the shape of the center being heavily boxed (hallway/bedrooms/bathroom with laundry/garage/stairway underneath). The signal I get on that side with the 5GHz network is more like 22%, which is about what all the neighboring houses report on their 2.4GHz networks, which is to say that's pretty bad and highly prone to dropping thus making 5GHz largely useless outside the room the router is in (where wired gigabit is available and thus moot anyway). Throw in the fact that 802.11G devices like iPhones and iPod Touches will slow your 2.4Ghz router down and you have one slow and/or unreliable 802.11N network that will make you wish you had wired Ethernet throughout the house.

    Devices like my Apple TV units usually do well regardless (they don't need 300Mbps to operate), but do sometimes go through fits of pauses (often during daylight hours when interference seems much higher in general), but this promise of 5GHz being the ultimate wireless network is just plain laughable given the problem that spectrum has penetrating solid objects compared to 2.4GHz.

    It is also worth noting that operating the 2.4GHz bandwidth in non-bonding (slower) mode often produces faster results since less interference results in better connections and thus faster overall transfers than a dual-channel but unreliable connection.

    I don't know off-hand if the latest iPhone4 and iPod Touches finally enabled 802.11N or not, but it's disconcerting that the capability has been in place at least a generation earlier but forced to run on 802.11G anyway, given the negative impact those devices have on a 802.11N network, which often leads to people keeping their old 802.11G neworks and only further crowding the 2.4GHz spectrum.
     
  2. cuestakid macrumors 68000

    Joined:
    Jun 14, 2006
    Location:
    San Fran
    #2
    I have found the same thing. At my house, the router is downstairs in my mom's office. I normally use my laptop right above her, so signal quality is never an issue. Yet, if I go to my room (maybe 45 or so ft from where I normally use it), I barely get a signal on my ipod touch and get very weak signal on my MBP. The problem is that we have a glass mirror, two thick walls and a glass door downstairs, as well as another glass mirror downstairs.


    However, Your short description about Wifi should be required reading for anyone buying a router. It describes a extremely realistic scenario and real-world results about how just about any router will perform.
     
  3. Aduntu macrumors 6502a

    Aduntu

    Joined:
    Mar 29, 2010
    #3
    No, you shouldn't be "clearing" 300Mbps. There's a big difference between link speed and data throughput. 802.11n is theoretically capable of 300Mbps with channel bonding, but it's not realistic.

    This is not a secret. Higher frequencies are faster, but not stronger. Lower frequencies are stronger, but slower.

    The frequency band is not a factor here.

    Nothing you have needs 300Mbps to operate. Your internet connection is nowhere near that speed.

    As far as I've seen, 5GHz is marketed as an alternative, not the new standard.

    The 802.11n standard wasn't ratified until late last year. What was being used was a draft standard. The vast majority of wireless access points were, and still are, 802.11g. iPhones and iPods use WiFi almost exclusively for the internet. An 802.11g network in the 2.4GHz band is sufficient for the speeds that an average broadband connection offers.
     
  4. SidBala macrumors 6502a

    Joined:
    Jun 27, 2010
    #4
    All those things you state in your OP are well known limitations of wifi.

    Wrong. But only your expectation is wrong.

    If you seriously expected to get 300mbps, then you obviously didn't do your research.

    Many times even half of that - 150mbps is hard to reach.
     
  5. MagnusVonMagnum thread starter macrumors 601

    MagnusVonMagnum

    Joined:
    Jun 18, 2007
    #5
    I was being facetious about the 300mbps (i.e. mimicking the marketing claims). But regardless, the latter two replies come across as pretty rude, IMO. I wrote this post to help people understand a little more about practical Wi-Fi versus the sales hype they're likely to encounter at any given store. Some of you may think this stuff is common knowledge but I beg to differ. Most articles on 802.11N rarely mention the limitations of 5GHz.

    Speaking as an electronic engineer, that's total nonsense. Wave amplitude determines strength, not frequency for goodness sake. Speed has nothing to do with it beyond a given wavelengths properties in the environment you're in and the amount of bandwidth required. How a signal is modulated can matter a great deal as well (e.g. amplitude modulation versus frequency modulation). What matters in terms of penetration through walls is the wavelength's ability to pass through a given material based on its density and other properties. If you were in a large open office, 5GHz would most likely give you the same relative range and power reception as 2.4GHz. Thus, whether the promise of 5GHz (the two benefits are less people using that frequency range and more non-overlapping channels enabling bonding to be a more likely scenario to produce faster results. It won't do you a bit of good, however if you cannot receive the signal because it cannot reach the room you wish to receive the signal in.


    Of course it is. 802.11G (and B) devices operate in the 2.4GHz spectrum as do many cordless phones and other wireless devices. That means the probability for interference is greatly increased in that spectrum. 5GHz by comparison is relatively empty and far less likely to suffer interference problems. Because the waves are closer together, less bandwidth is needed to transmit more information and so you have less overlapping channels, again increasing the liklihood of higher data rates assuming the environment (walls) don't weaken the signal too much.

    If you use 802.11G devices on an N network, it will slow your entire network down to G speeds while those devices are transmitting and receiving. The net effect is that you may lose 50% of any speed gains over G rates thus it is better to have a second B/G only network for those devices to avoid slowing down your N network, but that also means even more devices in that spectrum and further possibilities of increased interference, if not for your then your neighbors.

    For goodness sake man, some of us do more than just surf the freaking web!!! I have a home recording studio, for example and I regularly transfer work directories to my server as a backup. I encode movies for my whole house audio/video system on multiple computers at times and I need send the end result (anywhere from 1.2GB to 4+ GB for HD files) back to the server. A 2GB file can take 10-20 minutes (depending on the signal) to transfer over wireless. That same file takes closer to 3 minutes over gigabit wired Ethernet with a fast hard drive. Now try transferring 5 movies that encoded overnight and you're going to be sitting there even with close to 900Mbps throughput I get across Gigabit on average (3x the theoretical max of 802.11N and nowhere near it in practice).
     
  6. chrmjenkins macrumors 603

    chrmjenkins

    Joined:
    Oct 29, 2007
    Location:
    CA
    #6
    iPhone 4 is N, but 2.4 N. I haven't read up on N to know whether this is a router specific or standard limitation, but using 2.4 N with an airport extreme prevents you from using 5 GHz N.
     
  7. cuestakid macrumors 68000

    Joined:
    Jun 14, 2006
    Location:
    San Fran
    #7
    I have seen a few articles talk about the limitations of the 5ghz band though they fail to mention all the things that effect the signal quality(thick walls, mirrors, windows, ect).
     
  8. slipper macrumors 68000

    slipper

    Joined:
    Nov 19, 2003
    #8
    I'm not an electronics engineer. So the moral to the story is stick with my trusty Linksys WRT54Gv4 since i don't do any WLAN file transfers other than printing?
     
  9. joudbren macrumors regular

    Joined:
    Apr 13, 2007
    Location:
    Edmonton, Alberta, Canada
    #9
    Sorry, not correct. The Airport Extreme is a SIMULTANEOUS dual band router which means the two radios can operate independently and at the same time. It's like having two seperate wireless access points and they can even be assigned different SSID's. The only thing tying them together is that they connect to the same network. It's also part of the reason that the Extreme is so expensive. (albeit I think it's still overpriced even so....)

    Both 2.4ghz and 5.0ghz can connect with B/G/N modes and the slowest connecting device on either frequency will slow down the faster devices that are using the same frequency. That's the advantage of having a simultaneous dual band setup in that you can have your fast devices share the 5.0ghz band using N mode exclusively and then your slower devices can all share the 2.4ghz band in B/G/N mixed mode and not affect the faster devices on the other radio.

    Trade off of course is that 5.0ghz doesn't have the same range as 2.4ghz but it is usually faster and less subject to wireless interference if the range works for you. Another trade off is that most connecting devices don't have 5.0ghz support.

    In my case my ATV, ATV2, iPad and iMac all exclusively share the 5.0ghz radio in N mode as they support that frequency. Everything else in the house including my iPhone 4 uses the 2.4ghz radio in a mix of G and N modes. My house is an average size 1200 sq. ft. single level bungalow and my ATV2 is at one end of the house and the Extreme is at the other end and I get a full five signal bars on the ATV2 on 5.0ghz. YMMV of course. Cheers!

    P.S. To do this you have to give each radio a different SSID and then tell your devices specifically which radio to connect with if the connecting device supports both frequencies.

    James
     
  10. MagnusVonMagnum thread starter macrumors 601

    MagnusVonMagnum

    Joined:
    Jun 18, 2007
    #10
    Sorry, but B/G devices do not use the 5GHz spectrum. PERIOD. The advantage of a dual band radio is that you can let the B/G devices use the 2.4GHz band and let N devices use the 5GHz band and basically avoid the problem of G or B devices slowing your N network down, but with the caveat that your range in some environments is going to be greatly (possibly terminally) reduced. Oddly enough, "A" devices can use 5GHz, however (if you let them).
     
  11. slipper macrumors 68000

    slipper

    Joined:
    Nov 19, 2003
    #11
    Anyone? I was in the market for another wireless router and i'm debating to either get the latest and greatest Airport Extreme or comparable router or just get another trusty Linksys WRT54GL with Tomato or DD-WRT
     
  12. MagnusVonMagnum thread starter macrumors 601

    MagnusVonMagnum

    Joined:
    Jun 18, 2007
    #12
    I can only comment on routers I've tried. I've got Airport Express units (for the Airplay functionality, although I used one as a second network for two years) and I tried (and returned) a high-end Belkin 802.11N unit before settling on this Netgear WNDR3700 which replaced a Netgear WNR3500. The Belkin unit had no options for easily reserving specific addresses for various equipment and it had very poor range/speed in my house. The Netgear 3500 worked well for the most part, but about once every 4-6 weeks it would need to be rebooted as the wireless just stopped responding. That was annoying to say the least. The B/G Netgear I had before that worked great. I was therefore hesitant to get another NetGear unit but after reading the other reviews out there, they all seemed flawed in some fashion or another.

    The Netgear 3700 I'm using now has the best speed/range I've tried thus far and has dual-radio capability as well (both 2.4 and 5GHz networks at the same time). I've never had to reset it because of a problem with the wireless signal the past 6 months I've had it. I have had the device list of things like my printers disappear from OSX's "shared" menu until a reset before, but that doesn't affect them from operating. Bonjour devices like other Macs always show up, so I'm not sure what the issue is/was. I reset it the other day to play with a few things (2.4 without bonding appears to be more consistent in speed here than with it, possibly due to surrounding networks interfering) and they haven't disappeared since thus far. I'm more concerned with the wireless network being available 24/7 without a reset and it has worked fine there.

    I'm not sure how the Airport Extreme is doing these days (I remember lots of odd complaints in the past, but that was a few years ago), but the Airport Express was always reliable in staying up, but was considerably weaker and slower than either Netgear router. The Airplay jack is nice, but if that's all you need, you can get the new AppleTV for $10 less and use it for audio only even (well I assume that will still work; I've used a 1st gen ATV for audio only before; it didn't require a video signal connection to function; I set it up on a monitor and used in a room without one with "Remote" for some time) with the option of adding video later. I think Apple purposely cripples its range/speed so the more expensive Extreme always performs better. It also has no real use as a wired router since it only has one wired port.
     
  13. cuestakid macrumors 68000

    Joined:
    Jun 14, 2006
    Location:
    San Fran
    #13

    I have one as well-it is an excellent router. I also installed one at my parents house, as well as at a client's.
     
  14. dimme macrumors 65816

    Joined:
    Feb 14, 2007
    Location:
    SF, CA
    #14
    A little off subject but you guys are smart

    I have a 5Ghz N and a separate G router. I like having both running for the different devices we have. Is there a problem having both units next to each other, can they interfere with each other.
     
  15. MagnusVonMagnum thread starter macrumors 601

    MagnusVonMagnum

    Joined:
    Jun 18, 2007
    #15
    They could potentially interfere with each other if they overlap each other's channels on the same frequency (i.e. Channels 1, 6 and 11 do not overlap each other). But you indicated the N network is at 5GHz. G networks are at 2.4GHz, so if you do not use your N network at 2.4GHz, you probably have nothing to worry about.
     
  16. rkuo macrumors 6502a

    Joined:
    Sep 25, 2010
    #16
    I dunno, none of this is really news. The way 5GHz operates might be unintuitive to a real layman, but there are a clear tradeoffs and certain advantages.

    For example, I live in an apt. complex. 5GHz is very desirable due to every neighbor having a wireless network, and it only needs to penetrate one wall since my access point is in the living room.

    In a house, you can still work around the lack of range by installing multiple access points and either wiring them up or using the extend a wireless network feature. Sure, it would be nice for 5GHz to cover your whole house. That's not how it works.
     
  17. mulo macrumors 68020

    mulo

    Joined:
    Aug 22, 2010
    Location:
    Behind you
    #17
    ill troll a little bit.
    does OS X pick 5ghz over 2.4ghz if available?
    i'm sitting ~9 feet from my AEBS and i'm almost always on 2.4ghz. - which is sht as I have several devices on my net that are capable of 1gbit, of course I wont reach this on wifi, but a 120% increase does wonders.
     
  18. peskaa macrumors 68020

    peskaa

    Joined:
    Mar 13, 2008
    Location:
    London, UK
    #18
    There's an easy solution to the poor 5GHz penetration issues - repeaters. I use a Dual Band AirPort Extreme as my main base station, but dotted round my house are another two AirPort Expresses and a Time Machine - this ensures I get excellent 5GHz coverage over the entire house, without any dead zones or drops.
     
  19. MagnusVonMagnum thread starter macrumors 601

    MagnusVonMagnum

    Joined:
    Jun 18, 2007
    #19
    Just so you know, generally speaking, extending a network will bring it to a crawl. If you need a "signal" OK, if you need speed, forget about it. You'll be lucky to get 1/2-1/4 the speed you would get where the 2nd network extender starts if it were not extending. Multiple access points sounds nice, but beyond extending wirelessly, you would need an Ethernet cable run to the extension point to do it. In other words, such options have severe drawbacks as well.

    I get a much better 2.4GHz signal where I live if I do not bond channels. I may only average 90Mbps on the other side of the house, but that's better than an intermittent signal that does maybe 150 at best anyway and often drops and then connects at 32 and then reconnects at 90, etc. endlessly. Nothing like Apple TV dropping a connection even for a second to stall your movie. I can get the 5GHz signal there and Apple TV says it's a "strong" signal with its basic little bar graph (my MBP tells a different story) and it will stall also. Since going to one single channel away from the neighbors channels (nearest one is on 6 and 11 and I now use 1 and so there is no interference any longer and thus far I get a consistent signal that is faster than I normally need. Doing large file transfers over wireless sucks, but then it sucks over T100 Ethernet as well (i.e. I have to make sure I set my MBP and PowerMac to 1000 manually as "automatic" usually fails to make the proper 1000 connection. My wireless signal will often do 100 consistently. I average 900Mbps real world speeds on the hard wired Gigabit connection with modern hard drives on both ends in my den. With 4GB files, it's still not as fast I'd like, but the hard drives are as much the limitation as the Ethernet connection in that range for now.
     
  20. ntrigue macrumors 68040

    ntrigue

    Joined:
    Jul 30, 2007
    #20
    That can't be accurate as I have an Airport Extreme-N 50 feet away (three walls in between) from an Airport Express-N in the same room as my laptop and I see 21 MBps / 8 MBps.
     
  21. MagnusVonMagnum thread starter macrumors 601

    MagnusVonMagnum

    Joined:
    Jun 18, 2007
    #21
    What do you mean by 21 / 8? Where are you getting 21 and where and with what are you getting 8? Is that with and without extending or is that 2.4 versus 5GHz or what?

    In any case, 21MegaBytes per second is 168Megabits per second and that is a pretty good connection rate, especially at that distance (three walls don't matter much for 2.4GHz, but they probably would for 5GHz) but about half the theoretical maximum for 802.11N using bonding. 8MB (64Mb) is so-so at 50 feet.

    Also why would you bother to extend to the network in the same room that you are receiving it anyway? (or does your house go on further to other rooms that use WiFi?) In any case, I can only report my own experiences (mine came to a crawl using a Netgear router + Apple Airport Express when I tried it) and what I read about extending networks.
     
  22. ntrigue macrumors 68040

    ntrigue

    Joined:
    Jul 30, 2007
    #22
    Apologies, 21mbps. The Airport Extreme is 45 feet away from the Airport Express then 5 more feet to the laptop.
     
  23. occamsrazor macrumors 6502

    occamsrazor

    Joined:
    Feb 25, 2007
    #23
    Or you could get a Linksys E3000 (simultaneous dual-band 2.4Ghz and 5Ghz) that's now compatible with Tomato (and probably DD-WRT if you prefer that). I just got one, used with Tomato, and the combination is quite nice.

    http://tomatousb.org/download
    http://victek.is-a-geek.com/tomato.html

    One thing that hasn't been mentioned, Apple 802.11N clients (e.g. MacBook etc) are artificially limited from connecting to 2.4Ghz N networks using 40Mhz wide channels. If you want the throughput associated with 40Mhz wide channels you have to use 5Ghz. This is a limit imposed by the client, it doesn't matter what access point you have. Just FYI....
     
  24. webpoet73 macrumors regular

    Joined:
    Jul 29, 2010
    #24
    Can bluetooth devices interfere with 2.4GHz networks if the devices are in very close proximity to the base station?

    I get wildly different internet d/l speeds on 2.4GHz networks than 5GHz networks. (I have a simultaneous dual-band AEBS).

    On the 5GHz network, I get about 20Mbps d/l (according to speedtest.net) but anywhere from 4 - 12 on 2.4GHz network (all devices are G, I have no A or B devices).
     
  25. jjd macrumors regular

    Joined:
    Aug 22, 2003
    #25
    Sorry to dredge up an old post, but I have a question about ethernet connections. I have had it with wifi in my house (large, double brick) and I am having Cat 6 run to one end of the house (and using some Cat 5e to the other end of the house that I did not know was there - was in the walls!). I will have TC as my WLAN router, and two AEBS at either end of the house, connected by ethernet. I will plan to create new networks on each of the AEBS but use the same name and setting as the AEBS. I am told this is the way to do it.

    But, crucially, I am hoping to connect a number of devices to the AEBS via ethernet (ATVs, a MacPro, Mac Mini, PS3 etc) and am hoping I am going to get high speed for transfers as well as max IP connectivity. Can you let me know what settings I need to adjust to assure 1000 as opposed to 100 per your post?

    tks
     

Share This Page