To modify K1 2-band modules, first buy parts for the desired bands at http://www.elecraft.com/order_form_parts.htm#K1 Parts Then change (only) the necessary parts on the 2-band module. For 80, I believe that you have to modify the main K1 board as well. You will need the K1 manual to set up the new bands when you finish soldering. 73, Paul W8TM