Imagine the scene. You've
just pitched the caravan and you are looking forward to settling down with a cuppa and your favourite 'soap'. But you can't get a decent picture, no matter what you do to the aerial.
It's a problem more of us will face as the switch is made to digital TV. But there are steps
that we can take to get that
signal wherever we're pitched, according to Andrew Harris.
He's the managing director of RoadPro, which specialises in all kinds of 12V/240V electronic kit.
Hoist your aerial high
Many digital TV reception problems that caravanners experience are caused by the signal from the transmitter being obstructed, typically by buildings, trees or the landscape. Andrew explains that getting as clear
a 'view' of the transmitter as possible and a good aerial are great starting points. "In most cases, obstructions block the signals from the transmitter," he says. "A directional aerial is best
for the job; that's why they're used on houses. You can point them towards the transmitter for the strongest signal. And you need
to get it as high as possible. That's why you see them on chimneys."
In order to test this theory, Andrew and I took some digital TV kit to Daventry in Northants, which is an area of poor TV coverage. Broad Lane Leisure allowed us to set up a TV in a 2008 Bailey Pageant Burgundy to go fishing for a signal.
Find the right transmitter
Before we could start commending or condemning any equipment, however, we had to work out where our nearest transmitter
was. With analogue signals, the position of the transmitter wasn't that important as a weak signal would get you a weak picture.
With digital, a weak signal means there will be no picture.
The biggest disadvantage of digital terrestrial TV is that you rarely get a great result by just plugging in the telly and switching it on. Finding out which transmitter is likely to be the best at any site is becoming crucial to enjoying good reception. Also, if you visit a region that has switched off the analogue signal altogether, a digital set-up
is the only way you'll get anything. Your TV aerial instruction manual may have some information about finding the nearest transmitter. For precise info on exact locations, go to www.dtg.org.uk/transmitters and enter the postcode.
For our test, Andrew had looked up Broad Lane Leisure's postcode on the DTG website. This told him that transmitters in Sandy Heath, Sutton Coldfield and Waltham
were the nearest and gave their distances from the dealer. Although Sandy Heath was the farthest, DTG suggested that its signal was the most likely to reach us.
Use the right aerial
We used a Roadstar 12V Freeview set-top box, which is ideal for caravans as it doesn't need mains power. It costs less than £50.
This was connected to a small
LCD TV which we felt was fairly typical of the set-up you might see in a tourer.
The Roadstar's set-top box comes with a small omni-directional aerial on
a magnetic base so that's the
first one we used, to see what
the reception would be like. Andrew placed the aerial on
the Bailey's roof through the rooflight and connected it to
the set-top box.
Using the remote control, we completed a channel scan but nothing was found, just as Andrew had predicted. He tried using two Glomex omni-directional aerials
– one small and one large. Neither found any channels. "This proves that you'll need a directional aerial," he said, "and it needs to be as high as you can get it."
He said that to stand a chance
of getting a signal, an aerial
that could be pointed at the transmitter was the only hope. These are commonly referred to
as directional aerials. The Status 530/5 directional aerial comes as standard with the Bailey Pageant, so this was hooked up next. Even with the antenna extended to its maximum height, the Status picked up no more channels than the tiny omni-directional one had. This illustrates just how poor the reception was in this area.
After failing to have any joy
with either the omni-directional
or directional aerials, Andrew set up his company's four-section fibreglass mast with a domestic-style directional aerial. He raised
the mast to about 15ft and, using
a compass, aligned the aerial with the transmitter. Keen to see the results, I was surprised to see we
still had nothing. Back outside, Andrew raised the mast to its 20ft maximum. This time, we got two channel multiplexes (see box), which included all the main terrestrial channels, plus CBBC,
BBC News 24 and a host of others.
Extract from an article in the April 2008 issue.
Also covered: "Useful websites", "Signal strength", "Bright futures" and "No Continental divide"
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