G4NSJ – HF Aerials and Antennas

HF aerials and antennas:

The aerial is the most important part of any station. A modest transmitter into a good aerial will beat a big transmitter into a poor one every time. On these pages I describe the HF aerials I have built and used here at G4NSJ, and a few I have read about but not yet tried.

Most of them are simple and cheap to make. Some need nothing more than a length of wire, a few insulators and an ATU. Pick a heading below, or see the Site Directory for everything on the site.

Vertical aerials

A ground-mounted vertical has a low angle of radiation, which is good for working DX. It also takes up very little room in the garden.

A vertical for 20 metres. A coffee-break quarter wave vertical made from copper pipe and fed with 50 ohm coax. I built it in about an hour and the first station I worked was in Indonesia.
A 5/8th wave 20 metre vertical. The forty foot big brother of the quarter wave version. I hear more USA stations on it and get better reports.
10 and 12 metre aerials, the Sigma Venom. A CB 5/8 wave vertical adjusted for 10 metres. It is mounted only six feet up on a fence post. I have worked Australia and Indonesia on 100 Watts. Includes an audio message.
Solarcon Antron A99 vertical. A fibreglass vertical for 25 to 32MHz. What is it really, a half wave or a 5/8 wave, and how much gain does it have? Includes an audio message.

Dipoles and centre-fed aerials

The half wave dipole is one of the oldest and most effective aerials around. These pages cover the basic dipole and some of its relatives.

HF dipole aerials. How to work out the length of a half wave dipole and feed it with coax. My dipole for the five meg frequencies is only 16 feet high and works extremely well.
HF fan dipole aerials. Several dipoles fanning out from one feed point, giving a cheap multi band aerial on a single coax feeder.
Doublet aerial. A dipole fed with balanced feeder, and the many arguments about what a doublet actually is. Mine has one end held up by a flag pole. Includes a video.
Delta Match aerial. A way of feeding a dipole without cutting the wire in the middle. I first spotted one on a hilltop in Spain.
Carolina Windom. An off-centre fed aerial where the coax is meant to radiate. What the advert's "Dedicated Matching Unit" really is.

End-fed and long wire aerials

If you can get a wire up into a tree or onto a pole, you have an aerial. End-fed wires are easy to put up but need a good ATU and a good RF earth.

End-fed aerials. What an end-fed aerial is and how the wire, the transmitter and the ground work together as an RF circuit.
End-fed wire for top band, 160 metres. Top band is my favourite band, but few of us have room for a full half wave. How I make a shorter wire work. Includes a video.
End fed Zepp. How a length of 300 ohm twin feeder brought my 80 metre noise level down from 10 over 9 to around S6.
Long wire antennas. Not every end-fed wire is a long wire. A true long wire is at least one wavelength long, and gives gain along the line of the wire.
Grounded loop aerial. My forty foot high loop with a buried copper pipe earth, used mainly on top band, and how I think it works.

Directional and receiving aerials

Some aerials are built to pick out signals from one direction, or to receive with less noise.

Beverage aerial. A very long, low wire for receiving on the lower HF bands, with a narrow beam and low noise.
Log periodic antenna. A directional aerial made of many dipoles, which covers a wide range of frequencies.
Medium and long wave ferrite rod aerials. My ferrite rod aerial for the Pye PCR2 receiver, which cut out the local interference on medium wave.
Medium wave frame aerials. A simple frame aerial to build for medium wave listening and DXing.
Antenna switch for short wave listening. How I connect one aerial to several receivers, and which wire I use for wire aerials. Includes a video.

Feeding and putting up your aerial

Coax fed HF aerials. Why one coax fed aerial on several bands, with the ATU in the shack, may not be as good as it looks.
Insulators for wire aerials. The far end of a wire aerial carries a very high voltage. Tie it to a tree without an insulator and you could set the tree on fire.