Simple question about wireless channel

[Hector Agustin Cozzetti]

Hello,
I'm a new user of NS2 simulator. I have a simple question: i would like to
know if possible to set the various frequency of wireless (physical layer)
in NS2, to be more precise if it's possibile to use the different channels
(5.2GHZ, 5.9GHZ) and tecnology (802.11a,802.11g...) in the simulation.
If it's possible, Can you give me an example in tcl script?
Thanks very much :)