Wireless-N USB adapters are designed chiefly for N-networks and so – generally speaking – you won’t see an advantage if you use a wireless-N adapter on 802.11G or B networks. If you are connecting to G or B network(s), a high-power 802.11G adapter is actually a better choice than wireless-N adapters (generally speaking).
Alfa 11n USB Adapters: We offer the best 802.11n USB WiFi adapter available
802.11n wireless adapters only work optimally when connecting to a 802.11n that’s operating in 802.11n mode.
11n products have one of the following: “3 TX + 3 RX” , “2TX + 2RX” and “1TX + 1RX” ~ all of them using MIMO technology.
Alfa AWUS036NH and AWUS052NH is “1TX + 1RX”, so, that’s why you see only one antenna: For the 11n USB adapter, Alfa tested “2TX + 2RX” and “1TX + 1RX” before they made AWUS036NH. Then Alfa found “2TX + 2RX” was not working better than “1TX + 1RX” ~ because an external antenna is used, “2TX + 2RX” has 2 antennas and they are too close, which causes an interference problem.
Streaming media on a local-area network: 802.11n is best choice
802.11n wireless adapters only work optimally when connecting to a 802.11n that’s operating in 802.11n mode.
Wireless-N enables speeds up to 300Mbps and is backward compatible with 802.11g & 802.11b:
WIRELESS-N (802.11n) is the very latest wireless networking technology and is the best choice if you are using your connection for streaming media and/or heavy-traffic of downloads and/or uploads.