style="font-size:15px;"> Here’s how to use your television to pick up a 13.7 billion-year-old signal from outer space, in three easy steps.
1 Turn on telly.
2 Unplug satellite or cable box, unplug aerial.
3 Stare at static.
That ‘snow’ or static is background ‘noise’ generated by the soup of radio waves washing around the earth. When you’re tuned to Coronation Street, the signal is so strong you don’t see the noise. But when the telly has nothing else to latch on to it tries to translate the ‘noise’ into a picture, and ‘snow’ or ‘static’ is the result. Now turn up the sound and listen, because here comes the good bit…
Most of this static is caused by the radio and TV signals that are constantly buzzing around the world, Chinese minicabs, Somali weather men, Russian tank commanders. During the Battle of the Atlantic in World War Two a young telegraphist on a Royal Navy cruiser picked up what he thought was a coded signal from a nearby German U-boat. Out there in the Atlantic they tended to think about U-boats quite a lot. Nobody could understand the message or even recognise the code. The report was duly sent back to Liverpool to be pored over by the experts, who couldn’t understand how this message had come to be received in mid-Atlantic. It wasn’t any code or language they recognised. Then, eventually, its origin was tracked down. It was a short-range transmission from a Russian tank commander in Stalingrad, appearing as bright as you like thousands of miles away at sea. This is a shining example of the erratic behaviour of radio waves and their tendency to pop up all over the place, a syndrome known as analogous propagation.
But 1 per cent of the noise that you’re seeing (and hearing) is something else; it’s the radiation left over from the event that gave birth to the entire universe, it’s the receding echo of the Big Bang, now showing on your very own TV.
I’ll pause here while you take in the enormity of what you’re looking at. Now stare at the screen again. One per cent of that fizzing energy and activity is coming to you from something that happened more than 13 billion years ago.
For me this is a bit like smelling salts: you can use it to snap you out of any mood, at any time. And that’s not the end of it; the explanation of how we know all this is pretty good too.
How it works
If we’d always had digital tellies we’d never have seen this phenomenon. But in the old days of analogue, TV had to pick up a wide range of frequencies, and this microwave echo of the Big Bang – gradually fading as it spreads through our ever-expanding universe – just happens to overlap into the same range, so our tellies were able to see it. Its proper name is Cosmic Background Radiation (CBR). It’s on the radio too, somewhere in all that white noise between stations.
CBR was found by a pair of American physicists in the 1960s. They were trying to listen to the stars and were getting increasingly irritated by a constant noise on their super-powerful receiver. At first they thought it might be caused by pigeon poo on their dish, but they had it cleaned and it was no different. Then they wondered if it could be radiation from nearby New York, but they pointed their dish the other way and it was still there. Eventually they found it wasn’t even coming from within the galaxy, but was present everywhere, throughout the universe. Then they looked at each other and realised what it must be. They had found what’s left of the heat from the Big Bang.
SOFA SCIENCE LESSON
Whenever kids complain there’s nothing on, then, seize the chance to grab their attention by turning the TV into a cosmic data receiver. Relating it to Star Wars in some way might help too, depending on the demographics. But get it in while you can; before long all TVs will have built-in digital tuners, and it will be much harder to tune into the cosmos by just tuning out.
FORECAST THE WEATHER WITH INTERFERENCE
Once the whole Big Bang thing has sunk in, there’s still more to be done with the static on your out-of-tune radio and telly. This time, your TV is being turned into a weather detector, on the lookout for extreme events in the atmosphere.
ANALOGUE REVIVAL
To pick up the weather you need to be able to tune into the lower end of the VHF (very high frequency) band. This used to be packed with TV channels, but now they’ve mostly moved up to UHF (ultra high frequency), with the lower frequencies being phased out.
And now the onset of digital TV means that all analogue signals, even the UHF stuff, will be switched off, and new TVs won’t be equipped to tune into these analogue signals at all. This means that anyone with a brand new digital TV is going to miss out. It’s only a minor tragedy though; you can always go and dig the old set out of the attic. And if you haven’t got yourself a new set just yet, what better excuse to stick with what you’ve got.
Just because TV’s going digital, the laws of physics have no plans to follow suit, so these weather events are going to be on the same part of your dial for years to come.
LIGHTNING STORM ON YOUR TV
As soon as you hear thunder, get ready to catch a spectacular lightning storm on TV.
You need to be able to tune your TV to somewhere around 55 MHz. In the USA this is where you still find Channel 2. Some French channels broadcast on it too, but in the UK it hasn’t been used since the 1980s. None of that matters, of course, if you can tune it in manually.*
It helps to turn the brightness right down until you have no picture. When lightning strikes nearby it will throw bands of light across the screen, getting bigger the closer it gets.
This used to be a popular way to look out for tornadoes in America’s tornado alley (tornadoes are accompanied by lightning but also generate a signal themselves). So if your set does suddenly brighten for more than a few seconds at this frequency, and you can’t see lightning, it could well be there’s a twister coming in. Time to head for the cellar!
How it works
Lightning causes interference by generating a signal on and around 55 MHz. It’s strong enough to completely light up the screen if closer than 10 miles or so.
GOOD FORECAST, BAO PICTURE
The high pressure that brings good weather has an odd effect on your analogue TV. When the picture goes squiffy the consolation for the urban bushman is that it can be explained with a neat bit of weather science.
If your picture is normally clear and you suddenly start to see evenly spaced stripes or bars across the screen in a ‘Venetian blind’ effect, then there’s good weather on the way. That’s all there is to it really. Try adjusting the aerial. If you can’t fix it, the effect is definitely caused by high pressure. The picture won’t improve till the weather worsens, which seems fair.
There isn’t long left to view TV on an analogue signal, so make the most of this while you can. In our digital future it will become a distant memory. I already have my own nostalgic image stored away of a hot teenage summer trying to watch Borg and Connors battle it out over five sets through the stripey-green snow on the TV.
