I don't see it for sale anymore but the text is at https://dn760103.eu.archive.org/0/items/fea_Wireless_Digital... . No word on the fate of the "free disk," though.
The other recommendations you're getting are college-level texts. If McDermott's book suits your initial needs, Rick Lyons' and/or Steven W. Smith's DSP books would be a good next step.
Lesson 1: HAM is not an acronym. :)