There can be few of us who don’t know that the switchover to digital television has begun. By the end of 2012 the whole of the UK will be digital, there will be no analogue TV transmissions.

Digital transmissions offer many advantages over analogue ones – better picture quality, more channels, electronic programme guides and so on. However they do have one big disadvantage and that is that reception is pretty much all or nothing. The picture is either perfect or freezes frequently, or is completely absent.

Previously in weak signal areas we’ve been able to get away with aerials that were less than perfect by watching grainy or ghosted analogue pictures. When these areas go digital the chances are that the same aerial will give no picture at all.

As owners of caravans and motorhomes it is therefore important we invest in the right kit if we are to continue to enjoy television away from home. Basically we have two options – terrestrial (Freeview) and satellite.

For many of us terrestrial TV (Freeview) will be the simplest option. It offers up to 50 digital TV channels and 24 radio stations with no subscription. (There are additional channels that are encrypted but can be viewed by paying a monthly subscription. To get these you will need a receiver with a ‘CAM’ slot. This takes a device known as a Conditional Access Module which facilitates reception of encrypted channels.)

Most TV’s bought within the last two years will have come equipped with a Freeview tuner and earlier ones can be adapted by using a ‘set top’ box. These are inexpensive and many work off 12 volts supplied by a power brick for mains operation. On sites with no hook up the brick can be replaced with a suitable fused lead fed from the caravan’s 12 volt system. Pictured on the right here is a Philips Freeview box. The tiny size and 12 volt power requirement make it ideal for mobile use.
		Philips Freeview box

The next consideration is the aerial. Older caravans and motorhomes were often fitted with omni-directional aerials such as the Status S315 ‘flying saucer’. These only ever performed well in good signal areas with few reflections and, in my experience, are not best suited for picking up digital TV. On the plus side they need no setting up and can receive both horizontally and vertically polarised signals.

Status S315 aerial

Caravans and motorhomes manufactured within the last few years have been fitted with directional aerials such as the Status S530. These aerials are much better for digital reception but need to be pointed towards the transmitter. Where analogue signals are present this is fairly straightforward – you just wind away until you get the best picture. However, in areas where the TV signals are digital only, the chances are that no picture will be received until the aerial is pointing in the right direction – but how do you know where that is? The simplest solution is to look where your neighbours’ aerials are pointing and try that. A better solution is to buy a gadget to help. The simplest of these is a digital TV finder in the form of a signal strength indicator. LeisurePower sell one for £16.00, Maplins have a meter type for £19.99. These devices plug straight into the aerial lead and indicate when the strongest signal has been found.

Status S530 aerial

It is possible to replace the Status ‘flying saucer’ S315 with the S530. A blanking plate can be purchased to cover the area previously occupied by the S315 and then drilled to take the S530. This comes in short and long mast versions. The short mast version is used where the aerial is mounted above an overhead locker.

If you don’t want the hassle and cost of upgrading the S315 then a good free-standing aerial might be the answer. It needs to be able to pick up a wide range of frequencies so look out for ones marked ‘log periodic’ and ‘high gain’. Generally speaking the more elements the aerial has the better it will perform.

Freeview is easy to adapt to but does have some disadvantages. Firstly it will almost certainly be necessary to retune the receiver each time you arrive at a new site. This is because each transmitter transmits on different frequencies. Also some areas of the country will have a limited service with only half of the Freeview channels available. These areas will be the ones served by local relay transmitters. The missing channels will include Sky News, Sky Sports News, Sky Three, UKTV History, Dave, The Hits, Virgin 1, Film4, Five Live, Five US, ITV2+1 and E4+1. What’s more the limited capacity of these relay transmitters means they will not provide any digital signals until the analogue ones have been switched off.

The dark areas of the map should have good Freeview coverage; the light areas will have a half service or none at all

Satellite television can be a bit trickier to set up than terrestrial (Freeview) but, once mastered, it offers many advantages. The main satellites serving the UK and Ireland are the Astra 2/Eurobird 1 group located at 28.2/28.5 degrees east of south. Although the beams are tightly focussed on the UK and Ireland the signals can be picked up as far away as Spain with a suitably large dish. Another advantage of satellite TV is that there are far more channels available than on Freeview. At my last count there were something like 273 free to air TV channels and 123 radio channels. Some of the TV channels are repeats of the same signal whilst others are test channels and live feeds but the choice is still significantly larger than Freeview.

Of course to receive satellite signals a suitable receiver and dish are required. Receivers fall into three categories. The first to consider are standard free-to-air receivers. Many come in caravan friendly sizes and will work directly from 12 volts. They can pick up all unencrypted channels. You will be amazed how many there are, especially if you decide to tune in satellites from other areas of the sky. Prices start at about £40 (Maplins) and receivers sometimes come bundled with a dish and other accessories.

The problem with many of these receivers is that they can be complicated to set up, especially if you have no previous experience. You may need to get to grips with terms like ‘transponder’, ‘frequency’, ‘polarisation’, ‘symbol rate’ and ‘DiSEqc’ to name but a few. Don’t let this put you off though because, once tuned, a satellite receiver does not normally require retuning, regardless of where you are. If you can’t master it the chances are that someone else in the Club will give you a hand. If you want to avoid many of these problems look out for receivers that say they are pre-tuned for all UK free-to-air channels.

Next on the list is Freesat, the rival service to Freeview. Their receivers tend to come in caravan friendly sizes and some will work directly from a 12 volt supply. They pick up around 160 free-to-air channels, including radio stations and regional programming. The receivers are very easy to set up and use as well as having a good electronic programme guide. The downside is that they will only easily display channels belonging to the Freesat group.

Although Freesat offers more channels than Freeview, around 10 channels that are available on Freeview are not available on Freesat. These include ones such as Sky News, Sky Sports News, E4, More4, UKTV History and The Hits. I found this out to my cost when I bought a Freesat receiver and couldn’t find the channels I wanted.

		Legally Freesat receivers have to be capable of receiving all free-to air channels but my receiver made me tune the missing ones manually. This was a tricky process requiring me to look up and enter the broadcast frequencies and other details first. Even then the new channels were excluded from the main list and devoid of programme guides. Left is the Grundig Freesat HD receiver. It works off 12 volts and can send a stunning HD picture to a suitable TV
Grundig Freesat receiver

Freesat receivers fall into two types – standard and high definition (HD). The latter really need a relatively large TV (20” plus) to see the benefit and so may be overkill in a caravan or motorhome. Currently there are very few free-to-air channels broadcasting in HD. Prices for a standard receiver start at around £60 (Argos). No subscription is needed.

Last on my list are those receivers made for Sky. They tend to be large, expensive, mains powered and require a viewing card to see many of the channels. The folks at Sky really don’t want you to take your box away from home (where they can communicate with it via your phone line). Notwithstanding this some people do just that and enjoy a wide range of good channels at the cost of a subscription. You can substitute the subscription card with a free-to-view one (Solus- £23). This used to be needed to view ITV, channels 4 and channel 5 but these are now free-to-air and so can be viewed without any card or subscription. At the time of writing I am not aware of any additional channels to be had with a Solus card.

Having decided on a receiver the next choice is a dish. For use in the UK a 60 cm dish should be OK for most areas except Scotland where an 80cm dish might give better results. You can sometimes get away with a smaller dish but weaker stations may not appear and reception in rainy conditions may be affected. If travelling to the continent an 80cm or larger dish may be required depending on the location.

Setting up the dish can be the tricky. The Astra 2/Eurobird 1 satellites are located 28.2/28.5 degrees east of south at an elevation from the ground of between 26 degrees (London) and 18 degrees (Ullapool). A good compass can be a big help but will not help you to determine the elevation (up & down) angle of the dish. Dishes with an arm reflect the signal from the satellite above to a receiver known as an LNB at the end of the arm. This arrangement means that the dish will always appear to be looking lower in the sky than it actually is. Because the satellites are so close together most dishes will pick up both simultaneously.

To receive a signal the dish must have line of sight to the satellite. Any trees or buildings in the way will block the signal. This is where dishes mounted on tripods can be useful as they can easily be moved to take advantage of the best position for any given pitch. To determine whether the dish is receiving anything some form of satellite finder is required. These range from simple and cheap devices that emit a sound (the higher the pitch the stronger the signal) to sophisticated boxes that look for specific satellites and give information on signal quality as well as strength. The simple satellite finder on the right here is 10 years old but still works well. The tape in bottom right hand corner blanks the sounder and helps to cut down the rather loud noise it emits
		Samm 4 satellite finder

The angle of the dish is critical with a degree each way making a big difference. The problem with having a simple satellite finder is that it won’t tell you which satellite it has found and there are quite a few up there. With some practice it does get easier though. Two of the strongest signals come from Astra 1 at 19.2 degrees East of South (the original satellite used by BSkyB for their early analogue transmissions) and Astra 2 at 28.2 degrees. Astra1 is slightly higher in the sky so, if you have a strong signal but no picture, your dish could be pointing to Astra 1. In this case try going right and down a touch.

Once the satellite has been found the next check is to make sure that the LNB is rotated to line up accurately with the polarities (nominally horizontal and vertical) of the signal. All the TV satellites are positioned above the earth’s equator and so appear in an arc (a bit like a rainbow) when viewed from the UK. This means that the LNB has to be rotated to line up with the angle of the arc where the satellite is. This angle is known as the skew angle and, for Astra 2, varies from 14 degrees in London to 18 degrees in Penzance. When viewing the dish from the front the LNB should be rotated clockwise by this amount. Alternatively it may be possible to rotate the whole dish, depending on its mounting.

Conclusions
If you wish to continue watching TV in your caravan or motorhome you must go digital. Some areas of the country have already switched off their analogue signals and more are following. Freeview is a straightforward choice but satellite does offer advantages. It might be tricky to set up but, with a bit of practice, many will find it worth the effort.