300Mbps with Single Antenna

[sb1370]

As far as I know Wi-Fi 802.11n uses MIMO to reach 300Mbps.
But I've seen Wi-Fi adapters with a single external antenna. (such as this one or this)
Am I wrong?

 

[sfx2000]

One can have two radio chains with a single antenna... one loses a bit of gain on the combiner (about 2 dB or so), but the dipole on the device makes up for it.

Cell Phones do this all the time.

 

[azazel1024]

Its also quite possible that they are using a single external antennas for one of the radio chains and the second antenna is actually an internal antenna.

 

[sfx2000]

One thing that I hadn't considered - they could be considering use of TurboQAM and 40MHz channels to justify the claim of N300 capability - which in that can, it would be a single radio solution, and most folks would never see that kind of speed...

 

[azazel1024]

That would actually be non-TurboQAM. I have seen a number of dual band, single stream adapters billed as N300.

You just have to see if it is dual band N300, or single band N300. If single band N300, then it has to be two radio streams, whether it is an external and an internal antenna or two radio chains sharing the same antenna. If it is dual band N300, odds are almost 100% it is just 150Mbps on each band (even though client adapters are not concurrent dual band, so calling a 150Mbps adapter that is dual band N300 is misleading at best).

TurboQAM single stream 2.4GHz 40MHz would only be 200Mbps, so at best you could call it N200 or some perverted thing like that.

 

[sb1370]

Maybe a teardown would answer it. Also look at this.
By the way, considering it has a single antenna is it still faster than a 150Mbps adapter?

 

[azazel1024]

um, if it is truely dual radio chains off a single antenna, yes, it would be.

However, I am leaning towards marketing speak for dual band, single spatial stream/radio chain. So maximum link rate will be 150Mbps.

The Archer t2u is a dual band, 11ac adapter that is single stream. So 150Mbps 2.4GHz link rate or 433Mbps 5GHz link rate maximum.