Zyra's website //// Shortwave //// Radio //// Radio Astronomy //// Site Index

How to Build a Good Shortwave Aerial

A good shortwave / medium wave / long wave aerial can be made quite cheaply with standard parts scavenged from electronic junk. The only other things needed are good sense, a practical approach, and possibly getting on well with the neighbours might help too.

A radio aerial of this type is in essence a piece of wire which is hung up horizontally as high and as long as possible.

First get your piece of wire. One of the best places to look is inside a ruined television. The large transformers are good sources of long strong wire. Also, the deflector coil assembly around the tube neck may contain long coils of wire which can sometimes easily be unwound. Be careful what you do with the tv tube! If in doubt, whack the neck off while looking away from it.

Any long, strong piece of wire, whether insulated or enamelled, will do.

Incidentally, enamelled wire (copper coloured) can be connected to things only by stripping off some of the enamel at the ends. This can be done with a match, cigarette lighter, or even sandpaper.

Next, hanging it. Most houses have at least one chimney or flagpole or telly aerial, so that's a good starting point. The next thing is to locate another high point somewhere many tens-hundreds of yards away. If it's your neighbour's chimney, it's best to ask nicely.

Attaching the wire to the twin high points. Don't just tie the wire to the points, as this will cause signal to leak out. The way to avoid this is to use a yard or two of string as the last bit that ties round the point. Also, those snazzy insulators are handy if you can get them - the ones that look like two pairs of interlocking dentures. If not, it's just a matter of tying it on with string. Plastic string that won't conduct electricity in the rain is best.

So, having go a nice long piece of wire festooned across your garden from one place to another, it's time to put it into effect.

An earth connection is sometimes worth having. This is really just a wire clamped onto a metal drainpipe, or onto the plumbing. Some receivers need this, and some don't.

The classic oldfashioned wireless set will often function very well with just an aerial attached. The longer and higher the better. It is spectacular what some of them can pick up from right across the world. See spirit of the shortwave

It's also possible to use a long wire aerial and earth like this to power a crystal set. Although not in fashion anymore, these have the intriguing fact that they need no power supply. No batteries, no mains, no wind-up handle. They just work from the power in the signal coming in from the aerial. Instructions on how to build a crystal radio set are beyond the scope of this document, but there are many sites which can help on doing a search for "how to build a crystal radio set". The simplest form is just a diode and a crystal earpiece. Insist on it being a "crystal earpiece" when buying it, as the basic hi-fi ones don't work on this. The diode is a modern form of the crystal and catswhisker, except that it's encapsulated in a small glass bead so there's no need to tweak it. More advanced crystal sets have a tuned circuit with a variable capacitor and a coil of some sort. This gives you a choice of channels.

If you've managed to get one shortwave aerial up, and you fancy having another one, the best way to do this is to have it at right angles, with both meeting at the point where you've got the radio.

Other references: Radio, Spirit of the Shortwave, Maplins radio catalogue, crazy inventions