usb with low power or hardware failure dongle zydas

[couto27]

first of all i apologize if this question already being ansered .

in my place of work im surrounded with large metal walls and the only way to get wireless is with a 4 metres usb and a dongle in the end, so that my laptop can stay in the desk.
(im no aloud to use more or diferent routers)

ive being using a dongle xg-1211 zdlan with chipset zydas and it works fine on my previous macbook unibody.

but now that i bought a mb air rev i have an unexpected situacion.

if i use a 1 meter usb cable the dongle works fine, but if i use more than 1 meter cable , like 2, 3 or 4 metres the dongle doesnt respond.

i suspect that the air usb doesnt provide enough power so that the dongle are able to work.

i search and i present a few solucions that havent being tested , but i would like your advice

1- use a usb power hub in the end mac> 4 meter usb > power hub > dongle

wich power hub usb is recomended ?

2- buy this device http://www.bearextender.com/ and use it with a 4 meters usb cable.

again i contact the website and also i need a power hub usb in the end for the bearextended

3- what other solucions do i have ?

4- does the air usb has low power?

5- the rev B and C they have the same usb power?

thanks