why 153 157 are not allowed to bind as a 40MHz channel for intel's card?

[idata]

Intel only support {149, 153}, {157,161} to bind as a 40MHz channel. Is this a protocol requirement or just for intel's cards. If this comes from 11 protocol, which part made such confinement?

[GARRY_W_Intel]

Not sure which country you are in but in the 5GHZ spectrum not all channels are available in a given country. Part of the 802.11a/n 5GHz spectrum overlaps with radar and therefor the channles avaialble depend on the country you are located in. See http://en.wikipedia.org/wiki/IEEE_802.11h-2003 http://en.wikipedia.org/wiki/IEEE_802.11h-2003 and http://en.wikipedia.org/wiki/List_of_WLAN_channels# 5.C2.A0GHz_.28802.11a.2Fh.2Fj.2Fn.29 http://en.wikipedia.org/wiki/List_of_WLAN_channels# 5.C2.A0GHz_.28802.11a.2Fh.2Fj.2Fn.29

[idata]

According to the specs you can connect on 40 Mhz channels:149+1, 153-1, 157+1,161-1 (where +1 means above and -1 means below). No other combinations are allowed based on the specs.

All Intel 11n wireless adapters support 40 Mhz connection at the channel combination mentioned above.

[idata]

So, boil down to the bottom, why regulatory think 153+1, 157-1 is illegal? I don't think this is caused by hardware.