End Fed Antennas
One of the simplest antennas to make, deploy and use are end fed wire antennas. The number of variations are endless. Probably the most familiar is the end fed half wave antenna. But random length end fed antennas are also popular and offer the added advantage of being multiple band though requiring some sort of tuning arrangement. Some often used lengths are 35.5 ft, 51 ft and 84 ft, lengths I have played with. Most include 4:1, 9:1, 49:1 or other transformer, balun or unun attached between the antenna and a coax feedline which in turn goes to a tuner or directly to the radio. Almost all non-resonant end fed antennas benefit from a counterpoise. End fed antennas are set up in various configurations such as a sloper, a vertical, inverted L, etc. Their versatility both physically and electrically make them very attractive, particularly in portable situations.
A special case of the end fed antenna is the end fed half wave antenna. It is essentially a half wave length of wire fed at one end rather than in the middle as would be the case with a dipole. Its radiation characteristics are similar to a half wave dipole. They have to main attractions: 1) ease of setting up and feeding since only one support for the far end is essential. The driven end can literally be just inches or feet off the ground. 2) they can be used without a tuner on all harmonically related bands above the design band. So one cut for 40 meters can be used with no tuner on 40, 20, 15 and 10 meters. A negative is that they require a transformer, typically a 49:1 transformer to bring the approximately 2500 ohms impedance at the feed end down to 50 ohms. But my experience is that is a small price to pay for a very convenient and effective antenna. I currently use an mfj 1984MP, 40-10 efhw as my primary home station antenna these days. It replaces a G5RV which has served me very well for many years.