How to select wifi channel with windows 7 adhoc?
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.
Press the Windows logo and "R" keys simultaneously to display the "Run" dialog box. Type "devmgmt.msc" without quotation marks into the box and press "Enter." The Windows device manager will appear.
Double-click "Network Adapters" to expand the category.
Right-click your wireless network adapter and click "Properties."
Click the "Advanced" tab, then click "Ad Hoc Channel 802.11" under "Property" on the left side of the window.
Use the arrows on the right side of the window to change the channel. Make sure that you and your ad hoc networking partner select the same channel.
Click "OK" to save the change, then close the device manager.
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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.