The 49:1 Half-Wave End-Fed Antenna Transformer, Part 1. Post 2014.
If you can't see the video, please insert this title URL into your browser search box: https://www.youtube.com/watch?v=MgZap6xWZLs. One of the drawbacks to end-fed and random length wire HF antennas is the high mismatch between the antenna (often more than 2000 ohms impedance) and your HF transceiver (normally, around 50 ohms impedance). The resulting SWR will be enough to harm your rig. One way to reduce SWR and RFI concerns with these antennas is to use a 49:1 antenna transformer. In this video from the "Radio Prepper", we get an excellent introduction to the theory, construction, and use of the 49:1 balun. According to the "Radio Prepper", this transformer works well with wire lengths of 134 feet/40.85 meters and 67 feet/20.42 meters. Make one of these 49:1 transformers for your emergency "go kit" or for the next ARRL Field Day. A simple, easy solution for matching your HF rig to end-fed half wave or random wire antennas. For the lates