Revision C1 of the K4 operating manual can be found online at this link: https://ftp.elecraft.com/K4/Manuals%20Downloads/K4%20Built-In%20Operating%20Manual%20rev%20C1/K4BuiltInOperatingManualrevC1.html We’ll be updating the built-in manual (in the radio itself) in a future software release. 73, Wayne N6KR