G4NSJ – Long Wire Antennas


Many people refer to an end-fed wire of any length as a long wire antenna. This is incorrect. Just because a length of wire might be considered to be long because it’s the length of your garden, it’s not necessarily a long wire antenna.

A long wire antenna is where the length of the wire is greater than λ/2 at the operating frequency. For example, if an end-fed wire of 66 feet is used on the 40 metre band, it should be refered to as a half wave end-fed. If the same length of wire is used on 80 metres, it’s a quater wave end fed. However, if it’s used on 20 metres, it can be called a long wire antenna.

Any length of wire which is longer than a half wave at the operating frequency may be refered to as a long wire antenna. Technically, the length of a long wire antenna is usually considered as multiples of a half wavelength. I remember chatting to a G3 on 80 metres back in the 1970s. I said that I was using a long wire and he put me right!

I learned a lot from the old timers back in the 60s and 70s. They would chat away to each other on the 80 metre amateur band about aerials and aerial tuning units and I’d listen intently and take notes.

There’s more on end-fed aerials here.

More coming soon…