These two books are free.
1. K1TTT David Robins: BUILDING A SUPER STATION
713 pages – The history of building the K1TTT amateur radio super station in Peru, Ma. 30 Years of building, re-building, changing and improving plus lots of visitors and events. You purchase it at $0.00 which means free!
Free PDF download to your computer at this K1TTT LINK.
2. G3TRP Trevor Preece: THE THE VHF/UHF DX BOOK, 2017 Replica Edition
The VHF/UHF DX Book was written in the early to mid-1990s by a team of experienced VHF/UHF DXers and equipment developers, in an effort to pass on our knowledge and stimulate further developments. Looking back, that plan worked very well… for a time. But as we entered the digital age, information of lasting value became trapped on the printed pages and was lost to the next generation of VHF/UHF DXers. To keep that information alive, this digital replica of the Second Printing dated 1995 has been released by kind permission of the copyright owner TRPublishing and its proprietor Trevor Preece G3TRP.
Free PDF download to your computer at this G3TRP LINK.