Those are pretty wildly different topics For "radio" I'd recommend reading on Analog and Digital Signal Processing. Antenna theory is an entirely separate fiel

Those are pretty wildly different topics For "radio" I'd recommend reading on Analog and Digital Signal Processing. Antenna theory is an entirely separate field which you'd want to reference specifically. Ham is more of of the culture/context surrounding ham radio, and for that I'd recommend one of the ARRL exam study books from http://www.arrl.org/shop/What-s-New http://www.arrl.org/shop/What-s-New though for the easier tests these are pretty light on technicals and are more about policy and good radio operator behavior