END FED WIRE ANTENNA

 

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The end fed wire has to be one of the best cost effective and simplest multi band antennas. They are easy to erect and can cost almost nothing if you have enough wire handy. Almost any type of wire can be used, any medium gauge multi stranded pvc coated wire or single strand enameled copper wire. (I use 16 gauge pre- stretched enameled copper wire). This antenna will suit most houses and gardens as it can be horizontal, part horizontal, vertical or sloping to fit your available space.

Any length of wire can be used, but the length will determine which bands you can use. For shortwave listeners the lengths are not critical but for transmitting the chart below will give a good starting point.

WIRE LENGTH

BANDS

10.5m
40,30,17,15, and 12m

15.5m
80,40,20 and 12m

26.5m
All bands (tuning may be difficult on 10m)

The wire lengths above may need some alterations due to the geometry of your QTH, height and nearby buildings.

There are some drawbacks with this type of antenna, it is unbalanced and in some cases may rise to TVI problems in built up areas. It also requires the use of an ATU (antenna tuning unit) and you will also need a good earth connection. As you can see from the diagram the ground wire is connected to the the earth terminal of the ATU,  the other end is connected to a copper earth rod driven into the ground.  The longer the rod the better but the ground wire should be kept as short as possible. Use a thick heavy gauge wire such as the type used for car battery leads or the braid from a heavy gauge coaxial cable.

If your shack is on the first floor or higher it may be difficult to get a good RF earth.  If the ground lead length is more than a small fraction of a wavelength you may need to use an artificial ground. This is a quarter wavelength of wire for each band in use, they must all connect to the earth terminal of the ATU.  The wires can be run outside, concealed around the skirting board or under the carpet of your shack, make sure the end of these wires are well insulated or use pvc coated wire as the free end of a counterpoise wire will carry very high RF voltages when transmitting.  The counterpoise wires will also reduce or remove any RF feedback or transceiver instability.  



Another idea is to use a length of wire one half wavelength at the lowest operating frequency. This requires a less extensive earth system (An earth rod driven into the ground without any counterpoise wires.)





ALTERNATIVE CONFIGURATION TO FIT  AVAILABLE SPACE. 

WARNING=MAKE SURE THE END OF THE WIRE IS WELL INSULATED TO AVOID RF BURNS.

COUNTERPOISE WIRES MAY BE LAID ABOVE,  BELOW OR EVEN ON THE GROUND.

I would recommend the end fed wire as a good antenna to start the hobby as it requires very little expense. I have worked stations all over the world on 20 meters,  all over Europe on 80 and into central Russia on 40 meters. Although I have not called for any real Dx on 40 meters, I have heard stations as far as central Japan.

http://users.whsmithnet.co.uk/m0dad/Homebrew/end_fed_wire.htm