I made an adhoc network with Windows 7. Now I would like to change the wifi channel it is using. How to do this?
The ability to change the channel is a function of the wifi adapter driver. Some can, some can't.
If yours can, you'll find it in the wifi adapter properties.
When installing the Windows drivers for the Atheros device, the INF file may not have included Ad Hoc channel selection capability even though the wifi card is capable.
Look for 'defaultIbssChannel' examples in the INF file. You can then add this new parameter by using 'regedit' and add to the existing parameters that are available to the wifi card. Look in: HKEY_LOCAL_MACHINE/SYSTEM/ControlSet 001/Class/.....NDI/params
Eventually, you may want to modify the INF file and re-install the driver.
I had the same problem with the AR9280 chipset and was able to set the Ad Hoc channel by tinkering as above.