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Wi-Fi Is About to Get Faster

r00t4rd3d

Regular Contributor
This should be a good thing for us right?

Under the FCC's order, Wi-Fi routers will have access to an additional 100 megahertz of spectrum—the radio frequencies that carry all wireless signals. The spectrum, which is in the 5 gigahertz band, had been licensed to the satellite phone provider Globalstar, but the company agreed to the new rules after the FCC set interference standards.

http://www.nationaljournal.com/tech/wi-fi-is-about-to-get-faster-20140331
 
Mixed news. Good that more spectrum is being freed. Bad in that it is in 5 GHz, which has reduced range vs. 2.4 GHz.

But with 4x4 AC coming (AC2300), available channels are going to get gobbled up quickly.
 
Very. Though the indifferent news is, is that a lot of the 5.150-5.250GHz block was already okay for Wifi usage. 4 of the 8 channels in there are/were indoor use only and limited broadcast power (50mw). So, really, in the end, this is only freeing up 40-50MHz of actual new bandwidth that wifi couldn't use before, but it IS reclassifying the rest. So now all 100MHz is outdoor use approved and higher broadcast powers. Not sure if its up to 250mw of most of 5GHz, or the full (normal) 1w that the upper 5GHz band and 2.4GHz can broadcast at.
 
I recall that ihn 2.4GHz, 1W is permitted only for certain narrow-beam antennas. The is/was a formula for increasing radiated power as antenna beamwidth reduces. the principle was that reduced beamwidth leads to less interference.
This was a part of why the FCC mandated non-standard antenna connectors (RP-SMA or RP-TNC). But that was naive.
 
IIRC its 1w radio is the max, but there is standard on dBm for input versus EIRP that takes in to account the antenna size.

Basically the more directional the antenna, the less the FCC cares about how powerful the signal is.

http://www.afar.net/tutorials/fcc-rules/

So with a 6dBi antena, its 1w for transmit of 30dBm and EIRP of 36dBm is the maximum allowed. For every 3dBi increase in antenna, the radio power must be reduced by 1dB.

So the absolute max you can hit is EIRP of 52dBm with 22dBm of radio power (using a 30dBi antenna).

In 5GHz range, it is less restrictive (except for thos channels that have restricted EIRP/Transmit power, some are 50mw and some are 250mw and some are 1w full).

There doesn't seem to be a requirement to step down radio power as antenna gain increases, but there is still an absolute max radio power of 30dBm (1w) and a max EIRP of 53dBm, which is 1 dBm higher than 2.4GHz...but also can be achieved with a much lower gain antenna (so it can cover more area).

So for example you could have 15dBi omni directional 5GHz antenna using 1w of transmit power, to hit 45dBm EIRP, where as on 2.4GHz, because of the requirements to step down radio power as antenna gain increases, you'd be limited to 42dBm EIRP.
 
I have changed some of my 5 GHz devices upstairs to my 2.4 GHz wifi due to the reduced range.
 

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