Listener's Guide

The Long-Wire Shortwave Listening Antenna

We are on a shaky ground here. Rain forests have been felled to print the endless hallowed textbooks on the subject so we don't feel we should add to the debate. They are on the shelf, layered in dust just like the writer.

An installation from the 1920s

Your first point of reference is The Manual that came with the set. Have a read. The antenna stages of your radio will exhibit some kind of electrical characteristic. This is the impedance - the resistance offered to the radio signal at the frequency you are listening to.

If you follow the suggested designs in the instruction manual, then the burden of thought rests with the set maker and the aerial will be a good match. This has little to do with dating agencies - our good match is the best transfer of energy from the aerial to the radio that is all we are trying to achieve.

This can also be done without the slightest knowledge of the radio's input impedance, offering more reassurance to the beginner.

You will note the writer can't make up his mind on what term to use, antenna or aerial.

Current designers working in the white heat of new technology do seem to loose touch with the fact that the basic physics remain the same, only the top layer of jargon follows fashion. We belong to a select few who understand that marketing and brand-image still can't get over the physics of radio, no matter how big the budget.

The Traditional Long-Wire Antenna, as its name implies, is a simple single length of wire of a thickness strong enough to support its own weight, insulated or not, as long and high as the local geography allows.

Technocrats will call this an Inverted L as the longer limb of the capital letter L is the bit that runs down the garden, the shorter limb swinging down to form the downlead to the radio. Technophobes will say it is easy to put up. Simply use insulators at each of the three points of the L and you are away. If you feel this prose is labouring toward a What the L punchline, then there it is, with all the feeling of inevitability.

Try to form the aerial and downlead in a single unbroken length of wire. This will avoid making connections outside and the possible future effects of corrosion affecting reception.

If you are out in the country, a long wire can be very long offering some advantages at lower frequencies.

Keep it away from any overhead powerlines as their throbbing 11,000 volts will do little for the radio or your hairstyle. They are also the transmitters of electrical noise at the very frequencies you thought you were gaining some advantage by going for the big one.

Connect all long-wires great or small to the correct point on the back of the radio. While you are there you may see a large coaxial connector. This is for specialist antennas that achieve resonance - that is, a maximum efficiency at a single or narrow range of frequencies - a characteristic of them being a low impedance that may be carried by coax cable.

The advantage of a coax feed is the screening effect the cable has against localised interference, no special care has to be taken in the handling of the cable and, provided some effort has been made to match the coax at both ends, then the antennas can be remotely sited away from noise sources.

Our traditional long-wire will also be a low impedance at some frequencies so don't hesitate to experiment. You can calculate at what frequencies this will happen if you feel the need to. We prefer the suck it and see method as no amount of sums can argue with a higher signal meter reading.

Active Antennas For Shortwave Radio Listening

Over in Smug Corner sits the owner of a portable receiver. He knows - and we have to admit - that the performance of these sets is on the up. Flat-dwellers can forget all that has gone before and not bother about the politics of outdoor antennas and buy a portable happy in the knowledge that it will perform very well. They can also see if this is the hobby for them or check out local interference by getting one of the many entry-level sets coming out of China and still have FM stereo to fall back on if the bands are quiet. Don't you just hate it when that happens!

Yet they still enjoy their listening without all the discussion and installation of any special aerial array. How do they do it? The telescopic rod antenna on the portable is all they are using.

Remember what we said about any length of wire or rod antenna acting as an aerial as long as you can match its end-impedance to the tuning circuits in the radio? This is what the portables have done for years. The telescopic whip and the impedance transforming electronics form the basis of The Active Antenna. This is already a part of the portable, but if we separate them to allow the whip to be sited for best reception, if we go for pure design with less thought for cost and power consumption to improve IP performance, we start to have a real solution for those who do not have the space for a conventional antenna. If you are rowing the Atlantic in a dinghy this year, your dealer can supply an active antenna to receive from, but not send to, dear old Blighty. If you have the space for any kind of wire aerial, then do it.

Experiment to your hearts content, but just do it. To get an active antenna to turn in a real performance equal to our much-maligned bit of wire can lead to an investment near to the cost of the radio itself. Circumstances alter cases, so with the wide range of active devices available now, performance will not be compromised too much for the spatially-challenged. But do choose carefully.

Meanwhile in the snug of The Duck and Fruitbat, your scribe relaxes with several pints of Old McReekie's Intestinal Purge ready for some real radio. Just what are the Wild Waves saying?

The set is bought and installed by the book, the neighbour is already on to a legal beagle after seeing the antenna. But no matter. Time to turn on, tune in and drop out with the New Zealand fatstock prices.

Portable Shortwave Radios

This is a chance to score points off your elders and betters who inhabit a land where so much money has gone over the counter, they have Receivers, not a radio and have a bad case of the Rhombics for an antenna where we have got a bit of wire. If we have a portable radio we won't even have that.

Users of portable radios and scanners, those with a reasonable RF performance, get an early chance to visit Smug Corner. Even the small telescopic or helical antenna will deliver a signal, albeit at a changeable, usually high impedance and at a low level, the input stages designed to cope with all this. No antenna wires leave you free to listen anywhere, locations near windows giving best reception without the screening effects from any metalwork used in the building.

Portable users are strongly recommended to use a mains power supply when listening at home. This saves a fortune on dry cells and provides an earth path for unwanted signals. One of my sweeping generalisations is to state that DC battery power is up to 200 times more expensive than using the AC adapter.

Using rechargeables is a debatable saving as the convenience of not buying dry cells is negated by the lower voltage available and environmental issues about their disposal. A radio expecting to see 6 volts from four AA cells will only get 5 volts from a set of ni-cads, a loss of 16%. Not much in real terms, but enough to affect the RF performance of one of the better portables. If you have upgraded, the losses may degrade the new set to the level of the one just replaced. Remember; performance is such these days that each new model only brings an incremental increase in spec. Battery technology is improving all the time.

If the portable has an antenna connector, short pieces of wire can be tried, but don't go to any great lengths - pun intended - to put up big aerials for portables. Too much signal can cause more problems than too little.

For those of us who require an outdoor aerial - by far the best for general reception as we get away from electrical interference inside the house - we always recommend The Long Wire.

New Antenna And Nothing To Listen To

Last weekend, as the days lengthened over England, I went back to childhood and had an antenna rigging afternoon.

Why not use all that experience from Lowe's to get the best out of our hobby?

Why not? After all, I write this at a solar minimum so I'm going to need all those years of listening to hear anything. I've survived through four solar minimums so I can do this.

I now have a loop antenna, balanced against the noise, that was doing the business for the five minutes or so I spent testing it.

My problem is I can't find anything I want to listen to. Time was when I could write a schedule for a weeks listening across the main European broadcasters, before I ever went looking for that rare DX. The main draw for short-wave was news but you can get that anywhere now. BBC and CNN will give you two sides to a story. Do you need more?

There were those listener-help programmes like Waveguide, Swiss Short-Wave Merry-Go-Round and Media Network that dragged us anoraks in. Once hooked, you tended to hang in for the rest of the English Language portion of the days broadcast.

But what is there now?

Most stations are more news-lead now. The constant need for change means you have no idea when to listen as management goes for short-termism in programming. SWLs are traditional, hence the problem in getting new blood, but change for changes sake alienates. We need continuity.

The new audience - if there is one - will love DRM and will never notice that flagship programmes like Media Network once spoke to you rather than being just a web page, rather like this one.

A rainy day could be spent trawling the broadcast bands learning new stuff as innovation was the name of the game. That trawl takes less than an hour now. I know I'm older, less tolerant but SWL used to inspire. Now it's just more of the same, no matter where it comes from.

But I can't switch the set off. If you want a view of tradition taken too far, 80 metres on a Sunday morning is the place. Hams in ivory towers, GB2RS wondering how to get new people involved and asking where everybody has gone.

My most-listened-to channel?

5680 Search and Rescue; old values of courtesy and professionalism and that gentle air of contempt as they launch a several hundred thousand pound Nimrod to rescue a man on a three pound inflatable toy in the Atlantic.

SWL, you have changed. But come Saturday, I'll be back.

Whips And Wires

In an article written for AOR UK, the antenna stages of an AR7030 will exhibit some kind of electrical characteristic.

Classic Heath Robinson cartoon sums it up

This is a Complex Impedance, usually edited down to "impedance" - the resistance offered to the radio signal - for the sake of common usage. If you follow the suggested designs in the instruction manual, then the burden of thought rests with the set maker and the aerial will be a good match. This has little to do with Dateline - our "good match" is the best transfer of energy from the aerial to the radio which is all we are trying to achieve.

This can be done without the slightest knowledge of the radio's input impedance, offering more reassurance to the beginner.

The AOR Whip Antenna Option, a small telescopic antenna will deliver a signal, albeit at a very high impedance and at a low level, to input stages designed to cope with all this. No antenna wires leave you free to listen anywhere, locations near windows giving best reception without the screening effects from any metalwork used in the building.

The best reception is to be had from an outdoor aerial, as we get away from electrical interference inside the house - we always recommend The Long Wire. This is a simple single length of wire of a thickness strong enough to support its weight, insulated or not, as long and high as the local geography allows. Technocrats will call this an Inverted L as the longer limb of the capital letter L is the bit that runs down the garden, the shorter limb swinging down to form the downlead to the radio.

Technophobes will say it is easy to put up. Simply use insulators at each of the three points of the L and you are away. If you feel this prose is labouring toward a "What the L" punchline, then there it is, with all the feeling of inevitability...

Shortwave Antennas Revisited Again

Above me, I can see thirteen aerial reference books, most of them unread.

The reason for this is practicality. The man who designs the estate has decreed that the smallest distance between two houses will be called "the garden" and a long-wire aerial stretched to that distance will not resonate at any frequency you want to listen to. That's life.

In the end you put up piece of wire as long, as high and as neighbour-compatible as possible. You push the wire into the centre of the SO239 aerial socket and hope to hear something. You will, but it can be better.

Our AR7030 will take on the range of impedances and signal levels presented by the average garden long-wire and provide a much better match than using the SO 239, a co-ax connector strictly for 50 ohm resonant aerials. We use a carefully designed input transformer to get that match and provide a reassuring measure of static protection.

Long wires work best with a good earth connection. Traditionally, this was made to the rising water main but as so many repairs are now made with plastic fittings, it's just not reliable any more. Try Dracula impressions by banging a metal stake into the garden and connecting to the radio ground point with the shortest possible length of heavy-duty wire.

Tidy the mains lead to the radio by winding as much of it as possible around a ferrite ring. This should raise the impedance enough to leave the mains noise behind and leave a clear path from aerial to earth.