A free five part series on antennas that covers many aspects of antennas, from radio wave propagation, to feed lines, type of antennas, connectors, adaptors and antenna switches by Bob Grove, publisher of Monitoring Times
The Buddipole antenna is a very compact lightweight antenna that covers from 40 meters to 2 meters as standard and can be homebrewed to work on 80m and 160m or larger coils can be bought for 80m operation.
The DXZone is the largest human created and maintained library of web sites dedicated to Amateur Radio, currently lists 20.000+ links organized into 600+ categories and subcategories. Ham Radio operators review new sites every day since 1998, for potential inclusion in the Directory, and to evaluate the best place to list them
rpitx Multimode TX for Raspberry Pi, About Microphones - Guide to microphone for Ham Radio, Receiving GOES-16 Images with an RTL-SDR, EME Dish Antenna Project, CW and Morse Code Telegraphy, Pass Recorder, Morse Runner on MacOS,