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Salvage It! BY JULIAN EDGAR Scrounging & using shortwave radios This month, we’re going to make use of a discarded appliance that’s complete – no dismantling or salvaging of bits required! Welcome to the world of shortwave radio. Not quite sure what a shortwave radio is? Well, quite simply, it’s a radio that can tune in stations that operate at frequencies much higher than those on the familiar broadcast band. These stations also operate at shorter wavelengths than broadcast band stations (the higher the frequency, the shorter the wavelength), hence the term “shortwave stations”. With the ability of the web to run streaming audio from all around the world, listening to foreign stations via shortwave radio has dramatically declined in popularity. But take it from me, it’s a lot of fun exploring the shortwave radio bands and tuning in overseas stations. And best of all, it can cost next to nothing to obtain a shortwave radio and almost nothing to run it. That’s a lot different to paying for a PC and the bandwidth chewed up by streaming audio downloads! Shortwave radio stations are set up by countries primarily to present their political and cultural perspectives to the rest of the world. They’ve been doing that for well over 70 years but that doesn’t mean the program content is always dry – there’s music, news, talkshows and other program material, just like on a national broadcaster. What’s really interesting is the way This close-up view clearly shows the two shortwave radio bands (SW1 & SW2) on the dial of the old National Panasonic unit. in which world events are seen so differently by individual countries – it can be startling to hear the same news event described in terms that are completely different to what you are used to. In many cases, overseas broadcasts are nothing more than blatant propaganda but it’s still interesting to listen to other perspectives on world events. Buying a shortwave radio This old National Panasonic radio-cassette player was picked up at the local tip for just $5. In addition to AM/FM radio reception, it also boasts shortwave reception on two bands and has external aerial and earth connections. It also features a fine-tuning knob, making it perfect for listening to shortwave stations. 94  Silicon Chip Dedicated shortwave radios can be bought secondhand from about $30, or even less at a garage sale. Alternatively, you can buy low-cost units new for somewhere around $40. However, there are shortwave radios and there are shortwave radios – in my experience, the “cheapies” are terrible. In any case, $30 is outside our budget here. Instead, the trick is to find an old portable radio-cassette player – one that was once an expensive unit. In addition to FM and AM bands (and of course the cassette part as well), quite a few of these have shortwave reception. And they tend to be cheaper than dedicated radios – it seems no one wants cassette players these days! There are some key points to look for – the radio must have external aerial and earth connections and it must have siliconchip.com.au a fine-tuning knob. Let’s take a look at why each is required. Despite many shortwave radios using nothing more than a whip antenna, in most cases you really need a longwire antenna and an earth connection to get usable reception (they’re both easy to organise, so stay with us). Also, tuning a shortwave radio is a very different to tuning a conventional radio. In short, you need to be able to very precisely tune in a given station – hiccup and you’ll miss it. That’s where a fine-tuning knob is critical; without it, you’ll find that accurate tuning is quite difficult. Other features to look out for are those that you’d expect in any quality radio – things like a headphone socket, line-level outputs, and bass and treble controls. You’re not necessarily going to use any of these but their presence is evidence that you’ll got a quality piece of gear in front of you – one that is likely to give good shortwave reception. The radio-cassette player pictured here is a National Panasonic RX-5100 unit and was purchased from the shop at the local tip for a measly $5. It was in pretty good order but was missing its whip antenna and lacked a power cord. It also has some dents and scratches – the latter probably occurring when it was thrown on the tip. The volume controls (it uses dual controls) were also scratchy. But those quibbles aside, the unit works beautifully, with good sound and excellent shortwave reception. Aerial and earth After you’ve checked that the radio actually works (try it on the broadcast band), you’ll need to add an aerial and an earth. Connect the aerial first – some radios earth themselves through the mains power connection while in others, an earth connection seems to make little difference. The aerial can consist of any long piece of wire that’s supported as far above the ground as possible. That doesn’t mean you need to invest in tall masts and lots of high-quality wire – any wire that’s strong enough to support the span will do. You can string it between trees or from the roof of your house down to the ground, with insulators at the “tie-offs” at each end. The one I used is about 15 metres long and about five metres above the ground. What will work for you siliconchip.com.au An external aerial is a must for good shortwave listening but it doesn’t need to be anything fancy. Here, the aerial wire has been run from a short mast at left to the elevated house at right (ie, between the two arrows). depends a lot on the radio and your location – try different lengths and heights. Connect one end to the aerial terminal of the radio and try tuning carefully and slowly across the shortwave bands. You should now be able to hear shortwave stations that were previously buried in noise. Note that tuning a shortwave radio is not like twiddling an AM or FM dial: tuning slowly across the whole band might literally take you 10-15 minutes. When you hear a loud noise, fine-tune with the appropriate knob. Unless you’re very unlucky, you should be able to hear some stations – stations that your near-zero-dollar radio is pulling in from around the world! Once you’re hearing something, try adding an earth connection. This is literally a wire connecting the earth terminal to the ground outside – it’s best if you drive a copper stake into the ground or make a connection to a copper water pipe. If the earth connection improves reception, that’s great. If it doesn’t, leave it off. You’ll soon learn that analog radios tend to drift a little, so you will have to re-tune periodically to stay on-station. Note also that shortwave stations change the frequencies on which they broadcast at different times of the day. That’s done to counter changing reception conditions. So next time you see an old portable radio-cassette player going for a song, grab it and have a listen. Tuning in to the shortwave bands is lots of fun. SC Rat It Before You Chuck It! Whenever you throw away an old TV (or VCR or washing machine or dishwasher or printer) do you always think that surely there must be some good salvageable components inside? Well, this column is for you! (And it’s also for people without a lot of dough.) Each month we’ll use bits and pieces sourced from discards, sometimes in mini-projects and other times as an ideas smorgasbord. And you can contribute as well. If you have a use for specific parts which can easily be salvaged from goods commonly being thrown away, we’d love to hear from you. Perhaps you use the pressure switch from a washing machine to control a pump. Or maybe you have a use for the highquality bearings from VCR heads. Or perhaps you’ve found how the guts of a cassette player can be easily turned into a metal detector. (Well, we made the last one up but you get the idea . . .) If you have some practical ideas, write in and tell us! September 2005  95