Homebrew baluns by m0jha (BALancedUNbalanced)

Above are a few of my homebrew baluns.These are not hard to make and are inexpensive.All the above baluns probably cost less to make than one bottom end of the market commercial balun.Top left is a simple choke balun also called an ugly balun.Next is a 4.1 transformer for my loop antenna.The next is a tapped inductor for use with my mobile HF antennas.Its used in shunt with the feedpoint to match the low feedpoint impedence of my antenna on 17 and 20m to 50 ohm coax.The next one is a 4.1 balun.Bottom left is a 1.1 voltage balun with a 1.1 current balun next to it.The current balun on the right is made using ferrite rod.This one is ideal for portable antennas as its very light.When using a 1.1 balun i tend to stick with a choke balun or if using a toroid or ferrite rod i will use the current type winding arrangement.

Below a 1.1 current balun

Below is a simple 1.1 current balun. this will give a transition from balanced to unbalanced without any impedence transformation.I have used normal houshold wire to make it easier to see what's going on with wires. This particular one with only a few windings is only good for up to around 10mhz then the swr starts rising sharply. I have found 18-20 bifilar turns works ok through HF. Very simply one set of wires ( a brown and blue that leave the toroid together)would be connected to the dipole.It doesn't matter which leg of the dipole goes to which wire in this case. The other set of wires will connect to the coax. One wire to the live side and one to the shield.Again in this instance it does'nt matter which way round they go. Its no harder to house this in a box.Some people prefer using a 1.1 voltage balun which uses a third winding and is wired differently. The choise is yours.

Below is a 4.1 voltage balun

Below is a 4.1 voltage balun. You will notice its not much different to the 1.1 balun above with only a few changes. I have added the socket to make it easier to illustrate how its wired. The brown and the blue wire is the balanced side and is connected to the antenna. Again i have used household electrical wire just to illustrate the balun. I used 18-20 bifilar turns of 20 gauge enamelled copper wire and get a transformation from 200 ohms down to between 50-70 ohm across the HF bands on an analyser.This is good enough for my use.You can make these baluns on ferrite rods but again they need checking before use .

There are many designs for baluns and ununs ect on the net but i would advise to chech with an analyser before boxing up and sealing as many dont work as described.