No USB adapters showing 300mbps

[therawuncut]

Hey gang, this has been driving me nuts for several days.....

I have a WDTV Live Plus that I'm trying to do streaming on (standard 480p content and 720p only). Equipment in use :

Desktop PC with Airlink 6075 USB wireless adapter (also tried D-Link D-130)
Linksys WRT160N.

I get stuttering even when trying to play 480p content (cartoons). It even stutters going to my Dell Studio laptop that connects to the router at 270mbps, so I know the issue is occurring before the media hits the router. The Airlink (which sits 15 feet from the router, no walls) can only connect at 108mbps, and the D-Link adapter can only connect at 135. I have messed with 20mhz-40mhz settings and this hasn't improved things. Why is it that the Dell laptop connects at a great speed (even at farther distances, through walls, etc) when neither of these adapters will? Is there anything else I should look at?

 

[stevech]

have your tried connecting the laptop by cat5 ethernet wiring direct to the router, to begin a process-of-elimination troubleshooting?

I don't think you can expect good video streaming to a PC via WiFi. Assuming the laptop's video card/software is fast enough for the stream (prove/disprove as above).

I use MoCA because getting cat5 to the desired place/room was impractical. This eliminates the hassles of WiFi. You can also look at HPNA.

 

[therawuncut]

yeah i'm positive that the laptop can handle the stream. these are just 5 megabit MKV files. i used to stream to it using a wired cable in my last residence. I am looking at either beefing up my router/adapters, or looking at MoCA. Thanks for the assistance!

 

[keenanj]

Try the 600mW EUB9603H 802.11n USB adapter

http://www.keenansystems.com/store/catalog/product_info.php?cPath=2&products_id=314

The high power will go thru walls better than anything else out there and give you a consistant throughput.

 

[stevech]

Try the 600mW EUB9603H 802.11n USB adapter

http://www.keenansystems.com/store/catalog/product_info.php?cPath=2&products_id=314

The high power will go thru walls better than anything else out there and give you a consistant throughput.

That speaks to the Router-to-Client transmission.
What of the client-to-Router transmission (at much lower power)?

 

[keenanj]

The Receive Sensitivity on the EUB9603H is also very good (-90dBm) this allows it to hear a distant low powered router. Then the 600mW transmit power lets it go through walls and other obsticles.

 

[stevech]

The Receive Sensitivity on the EUB9603H is also very good (-90dBm) this allows it to hear a distant low powered router. Then the 600mW transmit power lets it go through walls and other obsticles.

-90dBm alone doesn't tell us anything. Usually, at -90, the bit rate is among the slowest, assuming no weak interfering signals (you are in a rural setting). In 802.11 (any) the required signal strength is proportional to the goal data bit rate. Conversely, for some received signal strength, a particular bit rate (speed) rate is viable. The WiFi alliance defines a standard error rate for receiver sensitivity - else vendors would run amok with claims irrespective of the bit error rates.

Due to the nature of 802.11, and the small number of chipset vendors, and the laws of physics such as noise-bandwidth-product and lots of other engineering, there can be very little difference between the vendor products receiver sensitivity. A product with a high power transmitter (more than 60mW) MUST have an expensive highly linear (no distortion) power amplifier to get to, say, 500mW, for 802.11n (OFDM). It's much easier/cheaper to get to 500Mw with 802.11g and far easier with 11b.

So in the fine print, if admitted at all, some vendors say that the higher transmitted power is achived only with 11b/g/n's lower bit rates. You can see this in the Cisco Aironet product specs and the like, but not in consumer gear. In simple terms, to get a higher rate there must be a higher signal (to noise + interference ratio). 802.11b always has far greater range than any other because its rates (bits/Hz/sec) are lower. The Hz is fixed by the standard at 20 (or now, 40MHz). The bits/sec/Hz is called the spectral efficiency - and the more bits/Hz/sec you strive for, holding the packet error rate constant, the more challenging the signal to noise + interference is. No matter the vendor.

Also, high power without good amplifier linearity (esp. for 11n) will distort the transmitted signal. The reported bit rate may be high, but the packet/frame error rate goes to pot - and negatively affects the IP layer. The WiFi alliance has requirements on transmitted waveform purity/distortion (Rho), but sadly, compliance is an honor system process.

Indeed, the power amplifier for 500mW or more is like 3/4 the cost of the entire device; so if you see a high power unit that's not a LOT more expensive than a 50mW unit, look at the fine print, if it's there.

In units with 500mW or more, there should but not always is a a low noise amplifier (LNA) on the receiver-side. This permits client devices to have much lower transmit power. If not, the range is not balanced, i.e,. one can transmit farther than one can receive, for a client with less power. The cure is to (automatically) reduce the data rate so that the client's signal can be received with the goal error rate. I like the rock band analogy: their amps create a very obvious unbalanced link! They can't hear you shouting unless you're in the front row.

The FCC has little to do with any of this, other than limiting max radiated power; they don't regulate signal quality (Rho) or error rates, for the unlicensed bands.

There is a lot of utter BS in WiFi marketing.

 

[keenanj]

Yes the highest power 600mW and best sensitivity is at 11Mbps 802.11b mode. But a solid 802.11b connection is much better than a flakey 802.11n connection and can still saturate most Internet links. Vendors advertise speed but range is still the most important to the end user whether they realize it or not.


That said this user actually needs the 802.11n throughput to stream local MKV files and the EUB9603h can do the job well. I stream both windows 7 media center .WTV files and .MKV files with no problems. The EUB9603h has up to 200mW and -85dBm in 802.11n mode where most other adapter have less then 70mW.

more info on the EUB9603H here:

http://www.keenansystems.com/store/catalog/product_info.php?cPath=2&products_id=314