The endfed antenna is a very popular antenna for home and portable operators. They can be effective antennas while also being relatively simple. An endfed antenna uses a matching network or transformer to get the correct match. They are similar to vertical antennas because they need some type of radial system to work properly. Not as much as a vertical, but some is required for best performance.

Why is there a 49:1 or 9:1 or 4:1 balun?
When we move the feedpoint of the antenna to the end, the impedance becomes very high – 2000 ohms or more. The transformer is used to reduce the impedance to ~50 ohms.

Why doesn’t a vertical antenna need a transformer?
That is because of the length of the antenna and where the antenna is being fed. If it were being fed from the center, it would be like a dipole; take an element of the dipole and stand it up, connect a bunch of wires to the opposite side, and lay on the ground – that’s a vertical.

PROS
Only 1 end needs to be elevated
Wire + transformer is easy to homebrew
Not as many radials are needed as a vertical
Can be stealthy if thin wire is used

CONS
Usually limited on power – check the manufacturer’s specs
Higher is better
Nearby metal objects can affect performance
Tuning may be needed if multibanded
Each band will behave differently

Variations
Endfed Halfwave
This antenna is very common. The Wire is half the wavelength of the lowest band.

Endfed Random
These are a favorite of builders and those trying to maximize space. It is considered a compromise antenna simply because it is not resonant on any band. A tuner is mandatory. This antenna can be multibanded, but should be at least half a wavelength of the lowest band.

Long Wire
This is like the endfed random antenna, except that the length of the wire must be over a wave length. Longer is better!

Zepp

These antennas get their names from the Zeppelin airships. Back in that era, a piece of ladder line was used to transform the high-impedance antenna to something more manageable.
Basically the same as a regular end-fed, except fed with ladder line instead.