Three Transistor Radio Ferrite Coil Antenna

I am using a ferrite rod approximately 10 mm in diameter, and the coil occupies a 6 cm length. Therefore, any rod longer than 6 cm is good enough, although ideally it has to be around 12 cm long.

For the coil, I am using a single core wire, which came out of a CAT 5 UTP computer networking cable. You require only 1-metre length of this cable, which you will need to open to get to the single wires. The MK484 radio project shows how to make this type of coil assembly. I chose this type of wire because it is cheap and readily available at any electrical and hardware store, but most importantly, it works extremely well due to the high specification copper they use to make the wire.

In this ferrite coil design, the orange/white stage consists of 24 turns, the orange stage is 24 turns, and the green stage is 18 turns.

The earth for the coil can be either after the end of the orange section, or green section, and there is a two pole selector switch to select between either of the two. By extending the coil with the green section, I am able to receive some additional stations in the medium wave (MW) band. The switch is optional because you may decide to have a longer coil all the time.

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