End fed wires

End fed wires come in all shapes and sizes. There are many names for these types of wire antennas like the random wire, long wire , inverted L , end fed sloper, 1/2 wave end fed , end fed zepp , and so on. They all have one thing in common and that is they are all fed at one end of the antenna against ground. These antennas when being used for multiband use are often substituted for other balanced multiband antennas with the builder under the impression the installation is going to be easier.This is not always the case and installing one that will work efficiently can sometimes be more time consuming and troublesome than a balanced antenna performing the same band coverage.

The above example could be fed a couple of ways depending on the intended use. NOTE this antenna must have a good ground connection to reduce any possible rf problems in the shack and/or home.

The half wave end fed

This is usually a mono band antenna. The set up is as above except the radiating element is a halfwave in length. Now because the halfwave will present a feedpoint impedence which is generally predictable it can be fed via a matching transformer and fed with coax. BELOW is an example of the type of transformer that could be used. For a known impedence transformation both L and C can be of fixed values but for a variable matching arrangement L can be tapped along with C being variable. This arrangement can also be used for vertical antenna ,again being variable or fixed values depending on the use. Another way of feeding the 1/2 wave end fed is via a quarter wave length of ladderline as this point should be reaching a current high and voltage low point.

Random wire

This name is a bit non descriptive of this antenna because rarely does one actually end up a true random wire. Amateurs that use this design will often of thought about how much wire they can use in the alloted space then from there work out what length provides the easiest matching. If being used on multiple bands some form of transformer will often be used. With this and the calculation for optimum length in mind the antenna is far from random. You may see some designs using a balun at the feedpoint and coax fed. The antenna is unbalanced and so is the feedline if coax is used so a better and more appropriate device would obveously be an unun . Again this antenna needs a good earth.

Grounding the antenna

Many people will install random wires, end fed ,verticals ect with minimal grounding. REMEMBER with these type of antennas what many people see as the antenna (the radiating part we see strung up in the air) is in fact only half the antenna. Disregard this very important point at your own loss. Many people will simply drive a ground rod into the earth and that be that. Ok it may "work" to a fashion in the sence you may be able to find a match with an atu but at the cost of efficiency. As stated many people will use this ground rod way of obtaining an earth and may never realise how badly the antenna actually performs against a well earthed antenna in the same set up situation. The antenna wants and needs a low impedence current return path which can only be obtained to a certain degree anyway by means of a good ground system. Time spent on a good ground system is time very well spent and can always come in useful for many other antenna projects.