This Sat-urday, my selected Amazon product is one of several books about Arduino and ham radio. ARRL has some good recent entries into this subject, too.
This one includes automatic Morse code decoding that I’ve used in an earlier form, mutated, and built with an added keyboard to send signals as well.
The author of the program published in the book, Budd Churchward, has an elegant, easy to assemble kit available with all the parts, or you could order bare printed circuit boards from OSH Park, Smoke Testing the Morseduino 2.
I’m also looking at a Hackaday article by Al Williams published today, Wilderness Radio Build, which features a built from scratch 20 meter transceiver, with video of its operation accompanied by a cat seeking attention.
Newer designs are using Software Defined Radio to control sending and receiving, sometimes standalone from a computer, such as this homebrew QRP (Reduced Power – usually 5 watts or less) transceiver QSO AE2B – PD5DJ/QRP with MCHF SDR Transceiver (embedded below). Shortwave (a.k.a. “HF” high frequency) can get your signal out of the local area when satellites are inaccessible for any reason.