Hi,
I work on computers, actually I swap parts on computers and some times I work on them also
I have noticed with Wireless N cards that some have 2 connection points on them and some have 3 - which means there are 3 (antennae) wires connected off a laptop wireless card for one Wireless N card and there are 2 wires coming-off a different version Wireless N card.
I was always under the impression that there was always two connections but the N frequency cards used the 3rd connection to alternate between frequencies allowing it to fare better with speed, range and stability. But if it’s true (my theory) then it makes no sense for there to be a version of wireless N that has only 2 connections on it.
What’s the real story anyone know? Are there certain benefits to one vs the other? Why are there 2 versions? I’d like to have the actual knowledge surrounding this curious question of mine.
I think this can get you started. As for why some have two and others three, maybe the card’s tuner/transmitters were improved to only need 2-antenna diversity.
We need a better paging system. I only found out that I’ve been paged by clicking on this thread.
The wireless N standard actually supports up to four antennas. From what I have seen, only the two and three antenna versions are common.
There are two different versions that use three antennas. One has three data streams and one only has two data streams. The way they number these things is (number of transmitters) x (number of receivers) : (number of data streams), so 2x2:2 has two antennas on each end and 2 data streams, where 3x3:2 has three antennas on each end but only two data streams.
3x3:2 is more common now, but 3x3:3 has been becoming more common lately. 3x3:2 effectively doesn’t have any greater bandwidth than 2x2:2 since in either case there are only two data streams. 3x3:3 is faster though because of the extra data stream.
As for why there is 2x2:2 and 3x3:2, the 3x3:2 gives you better range and a bit more robust of a signal, but costs more due to the extra hardware involved.
The wireless N standard actually supports up to 4x4:4.
ETA: Wireless N also supports 1x1:1. You don’t always have at least two data streams. I don’t think 1x1:1 is very common these days.
Err, your answer begs the question though that is: “How can I tell the difference between these or even what I currently have is doing in regards to transmission?”
You can look at the specs for the card, though a quick google search shows that a lot of them don’t provide enough details in the online specs. You may be able to find the specs you need at the manufacturer’s site though.
Some of them do advertise that they have 3 data streams. The other way to tell is the bandwidth spec for the card. If it lists 300 Mbps it’s a 2 stream card and if it is 450 Mbps it’s a 3 stream card.
