It's a bit of a tragedy, really. The BBC and ITV companies did a really good job of engineering the British TV transmitter network to give good picture quality with a rooftop aerial. So what do we do. We don't generally use that design to get the good quality the engineers of the 1960s aimed for. We use the good signal strength to try and get away with the least we can. Most of us want an easy life, and rooftop aerials are hard to get at and mean getting someone in. The sad thing is that we tinker with all sorts of rubbish and often spend much more in little bits and pieces than the about £140 average  it would cost to get someone in to do the job properly. So before you start, you ought to ask yourself what are your requirements and constraints. DIYers fall into three broad categories
|Group||Ability/ inclination to adapt living space - drilling holes, rigging stuff on roofs etc||Cost more important than performance?|
|Students, short term residents||nil||cost paramount. Not usually home cinema enthusiasts - students usually have other priorities|
|flat owners/tenants||limited||vary across the spectrum|
|house owners||unlimited unless restrictive covenants||vary across the spectrum|
Students are a special case deserving of their own page because of their unique constraints, frequent technical prowess and tendency to tinker, and fondness for silver bullets :-) All the other groups need work out which end of the cost/performance range they're in. You can skip the background and go right to the techy bit if you wish.
If you're a flat owner after DTT you should first see if the existing aerial socket delivers you a signal you can use. Communal aerial systems are known as SMATV or MATV systems which are now migrating to Integrated Reception Systems (IRS) which use a communal set of roof aerials and/or dishes and specialised parts to distribute satellite, analogue and DTT in communal dwellings. It's something you landlord or building facilities management will have to do. The old aerial system that's been in service since the 1970s will hardly ever deliver satisfactory performance. so you'll have to get them to upgrade.
Alternatively, look out your balcony. If you see the back of other people's TV aerials in the distance and there's nothing like another block of flats, you're in luck - you're on the side facing the transmitter. Continue using the same parts as a loft aerial - and make sure it can't fall off onto somebody's head! You'll probably get better performance than a householder with a loft aerial as you have the advantage of height, and no roof in the way.
If you see the tips of other people's aerials facing you, you're out of luck. You're on the wrong side of the block from the transmitter. You might be able to catch a reflection from a large building in front of you, but the chances are slim. Time to press the landlord for an IRS upgrade of the communal system.
If you're out of luck on DTT you still may be able to get Freesat or Sky Digital. Just stand outside your block and see how many of your neighbours have dishes!
Before you undertake a DIY job, you should take a quick look at the DTT conundrum so see why this may be different from when you did your last analogue aerial. DTT is different, and you're headed for a world of pain unless you have a feel of how it is different. You also really ought to take a look at Freesat, especially if you have an old satellite dish on your wall!
First off, put your postcode into the Freeview checker If it says sorry, you're out of area, you're most likely not really in the DIY install region. Call a CAI contractor for a quote, and compare it with Sky Digital.
So you've thought about where you are in the cost/performance area and you either
If performance is what you value, then you have ask yourself whether you are not better off with Freesat or Sky Digital. Sky has a much wider range of channels, and a transmission path which is known, stable and not susceptible to interference in the way terrestrial broadcasting is. It also offers you HD to feed your plasma telly, which DTT is highly unlikely to offer for the foreseeable future. Of course, Sky Digital costs more - £400 a year plus on average. You don't get 'owt for nowt. For range, quality, reliability and stability it wins hands down. Freesat offers you the same quality, reliability and stability, just with fewer channels.
So you've thought about that, and you don't like the idea. Maybe you hate Murdoch, or the thought of five grand to his evil empire over the next ten years doesn't light your fire, but you are still performance conscious and don't want an ugly satellite dish ?
Do yourself a favour and first call a CAI contractor for a quote, particularly if you want DTT. Which you generally do, as the analogue alternative ceases in 2007. It will set you a benchmark. Even the upper end of a normal domestic rig is half the cost of Sky for a year , and you will never achieve the same quality of install by yourself unless you buy the test gear, which makes even Sky look cheap. And learn how to drive it.
The benchmark set by the quote then basically defines your budget. If you are quoted in the high range, maybe you want to ask for another quote. If it's also high, you are in a difficult signal area. A DIY install will probably never give you an interruption-free picture unless you spend more than the quote. You're either going to have to eat that fact, or spend the money - either on bits of kit to DIY, or on the contractor. Only the contractor comes with a guarantee...
Still want to DIY? As long as the Freeview site didn't tell you you're out of area, go to the Wolfbane site to find out your transmitter, and then check the line of sight from your location to the transmitter with Terrain. If you have a clear line of sight and are within 20 miles of the transmitter you're probably going to be okay with a loft aerial.
Line of sight just grazing or clear but you are more than 20 miles from the transmitter? You're probably into roof aerial territory. You want to check your head for heights, ladders, life insurance and the cost of parts against the quote. It is certainly feasible to do a DIY roof install provided you are competent to go on the roof. Whether it's cost effective is something you should weigh up before getting any kit.
Something else you ought to consider is that if you do try DIY and decide the results don't meet your requirements, the cost of what you've bought so far will be lost. An aerial contractor worth his salt will probably refuse to use these parts. Which is fair enough - if he is going to guarantee the results, which he should, then yoy have to give him control over selecting all the parts.
I'm not trying to put you off the DIY route - but you should take the decision which way to go knowing as many of the facts and the financial risks as possible. I've always done my own TV installs, and my path to the main transmitter is over 20 miles. But there again, I've been able to borrow the test kit which I've used for SMATV line-up from work. Even then I used an aerial contractor at one house for FM, because my requirements were high and the location measured bad for FM. I didn't want to mess about trying different aerials in a difficult location so I was happy to pay for the experience of others.
You value cost more, so Sky Digital probably isn't for you. Take a look at Freesat. No good? As long as the Freeview site didn't tell you you're out of area, go to the Wolfbane site, and then check the line of sight from your location to the transmitter with Terrain. If you have a clear line of sight and are within 15 miles of the transmitter you're probably going to be okay with a loft aerial using a CAI benchmarked aerial (more details on the loft aerial page).
Line of sight obstructed or clear but you are more than 20 miles from the transmitter? You're probably into roof aerial territory or out of range. The cost of this will probably be more than you want to pay. Consider yourself in a marginal location for your budget. Reassess the contractor's quote - if it's not to your liking then hold fire.
As long as the Freeview site didn't tell you you're out of area, go to the Wolfbane site and then check the line of sight from your location to the transmitter with Terrain. If you have a clear line of sight and are within 10 miles of the transmitter you're probably going to be okay with a loft aerial using a CAI benchmarked aerial (more details on the loft aerial page).
Anything else and you can consider yourself in a marginal location as far as your upgrade budget is concerned.
If your location is outside your upgrade budget, you can probably still get DTT - just not yet. Stick with analogue, and make the jump to DTT at the last minute, preferably after they've switched analogue off in your area if you can do without the telly for a week.
The reason for that is that DTT will be a hell of a lot easier to receive once the spectrum is free of analogue signals in your region. And the DTT network will be better by then, and DTT receivers will work better in the face of interference.
Here's an introduction to the various components you tend to use in a domestic aerial system and how to use them, classified into the good, the bad, and the ugly. Your aim is to use the good, correctly, and none of the ugly!
Aerial system components
Picture quality with decreasing signal levels
real aerial measurement of DTT performance with decreasing signal levels + adding booster
experiment demonstrating boosters don't compensate for aerial deficiencies
Improving noise figure with boosters
Why DTT is different from an analogue install