What’s the dif­fer­ence be­tween… 2.4 and 5GHZ?

Computer Active (UK) - - Problems Solved -

QIn as much as I don’t re­ally know what my dual-band router is do­ing much of the time, and still less which band my lap­top or tablet use to con­nect, I do of­ten won­der what the prac­ti­cal dif­fer­ence is be­tween the 2.4 and 5GHZ stan­dards? I’m pretty sure my lap­top must be 2.4GHZ be­cause it’s quite old, but I can’t say internet stuff feels sig­nif­i­cantly slower than on my new ipad, which I as­sume con­nects via 5GHZ. So, could you ex­plain in sim­ple terms the dif­fer­ence be­tween 2.4 and 5GHZ?

Alan Wright

AWe could write pages on this but space is lim­ited! Fun­da­men­tally, they’re dif­fer­ent parts of the ra­dio spec­trum. As a rule of thumb, the 2.4GHZ band en­ables greater range at slower speeds, while 5GHZ sig­nals are able to trans­mit more, and faster, but over shorter dis­tances. That’s be­cause the laws of physics dic­tate that higher-fre­quency ra­dio waves aren’t as good at pass­ing through bar­ri­ers, such as walls or doors.

In ad­di­tion, there are nu­mer­ous tech­ni­cal specifications that de­fine the way com­puter data is sent and re­ceived by routers and the de­vices that con­nect to them. These are the var­i­ous stan­dards with 802.11 pre­fixes that you’ve prob­a­bly seen re­ferred to in print, on­line or on pack­ag­ing.

An an­cient 802.11b router, for ex­am­ple, is able to com­mu­ni­cate only over the 2.4GHZ band – and at speeds of up to 11Mbps. By con­trast, a more mod­ern 802.11n router will be able to use ei­ther (or both) bands, and will typ­i­cally of­fer speeds of up to a the­o­ret­i­cal 600Mbps. The lat­est 802.11ac routers go faster still (up to 1300Mbps or 1.3Gbps) – though some man­u­fac­tur­ers em­ploy tricks to claim even higher speeds. The nextgen­er­a­tion 802.11ax stan­dard pushes these the­o­ret­i­cal base­lines even fur­ther.

Some peo­ple favour the 5GHZ band, sim­ply be­cause it of­fers more user chan­nels and is con­sid­ered less con­gested. Reg­u­la­tor Of­com main­tains an in­ter­ac­tive ‘map’ of the UK’S ra­dio- spec­trum al­lo­ca­tion. You can ex­plore it at www.snipca.com/27717. How­ever, in prac­tice, most of the time most peo­ple don’t need to think or worry about any of this. Gen­er­ally, mod­ern wire­less routers and the de­vices that con­nect to them find the best way to com­mu­ni­cate with each other, be that over 2.4 or 5GHZ ra­dio waves.

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