Arrl 2019 radio handbook pdf download
Some QRPers prefer to construct their equipment from kits, published plans, or homebrew it from scratch. Many popular designs are based on the NE612 mixer IC, i.e. the K1, K2, ATS series and the Softrock SDR. Newington, CT: American Radio Relay League. pp. 22–24. ISBN 978-0-87259-694-8.