Home Hub 3 is a single-band 2.4GHz-only router, but 2.4GHz is the band that's caused me least problems after upgrade to iOS 8 so it may be what you need anyway. You can, however, change channels. This may prevent interference from other devices.
To change channels:
Open your web browser and type in http://bthomehub.home to open the Hub Manager. (You may be asked to change the password).
Click on Settings and enter your password, if required.
Click on the Wireless tab.
Find the Channel Selection option and using the drop down menu you can choose a new channel.
First try channels 1, 6 or 11, but others may be better. (Experiment)
Click Apply to confirm the change. Then wait 60 seconds for your computer to automatically discover the new settings. There's no need to change any settings on your computer