If you have a high-gain aerial or use signal amplifiers, it is quite common to find that the high-power digital signals provided after switchover will overload your Freeview equipment – and can appear to be “weak signals”.

Eliminating other possible problems first

The first is that very, very old equipment will not function with the digital signals split into 6,817 sub-signals, as it was only designed to work with 1,705 sub-signals. This is known as the “8k mode issue” – see  TVs and boxes that do not support the 8k

It is also common that people do not clear out the old channel list (by selecting “first time installation” retune, “Factory Reset” or “Shipping Condition”) before doing an “autoscan” for the available broadcast frequencies, and this results in everything from missing channels to no subtitles, programme guide, wrong channel numbers and no text services. If you can’t find how to do it see either  Freeview Retune – list of manuals or do it this way:  My Freeview box has no EPG, is blank, has no sound or the channel line up is wrong.

A third problem is caused by having signals from more than one transmitter – see DigitalRegion Overlap.

The final very common issue is “too much signal“.

Transmitters have much more digital power after switchover

At most transmitters, the digital signals after switchover are considerably more powerful than before. This was because when the analogue and digital services ran together, the digital services were kept low to prevent appearing as snowy interference on television sets using analogue reception.

Here is an example, from Sutton Coldfield, of how the signals change at switchover:

4,000kW of analogue signals are turned off, and the digital services increase in total power from 48kW to 1,200kW – that is an increase of 25 times in numerical terms, also know as +14dB. (The reduction of -7dB from the analogue strength is intended – the digital services require less power to cover the same number of homes).

This large increase in power should cause no effect for most people. A stronger signal does not increase the picture quality (you need Freeview HD for that), sound levels – the only effect should be that more homes that are further away from the transmitter mast can receive a stable digital signal.

High gain aerials and signal boosters

However, many people have been tempted into buying one both high gain aerials and signal boosters.

High-gain aerials were very suitable for places where the Freeview signal before switchover was very weak indeed, but if you have one of these and you are located closer to the transmitter, you will probably now have a signal overload.

Generally speaking, signal booster devices are never really much use for Freeview reception, and much of the time they actually amplify the interference more than they do the signal, causing reception to get worse, not better.

How to tell if you have too much signal

There are almost as many ways for a Freeview box to display the “signal strength” and “signal quality” as there are types of Freeview box. Here are some of them:

Speaking generally, there will be two indicators:

One is signal strength – this shows the power level of the signal entering the Freeview box. Often “0″ is the lowest and “10″ the highest, but sometimes it can be a percentage, sometimes coloured boxes and so on.

The signal strength should be around 75% – more than this indicates too much signal.

The other measure is the signal quality and this is much more important to high-quality Freeview viewing. Any measures that increase this to the maximum will provide for uninterrupted viewing, lower values will result in “bit errors” that cause the picture to freeze and the sound to mute out.

One problem with over powerful signals is the overload can sometimes show as a low signal because the receiver circuitry will enter a “blown fuse” state to protect itself.

How to deal with too much signal

First, if you have a booster or amplifier – remove it from your system. Don’t just unplug the power, as this will result in no signal getting though the device.

If you can’t just disconnect the output cable and connect it to the input cable, you might need a coax female-female coupler to connect two male connectors together.

If you don’t have a booster or amplifier, you might have to fit an attenuator onto the cable. They come in two types, either a “single attenuator”, around five pounds, or a variable attenuator, for around ten pounds. The variable sort has a knob that can be turned to select the required level of signal dampening.

Original from Brian Butterworth  (More Content at http://www.ukfree.tv)

OFCOM has announced it will currently not be reserving an HD slot for Five on Freeview. In June 2009, Ofcom made a provisional decision to reserve a HD slot for Five to provide new services on Freeview from 2010. This decision was subject to it resolving certain key criteria by the end of 2009. In OFCOM’s final decision published today (15 March) the regulator stated that Five had not been able to resolve the outstanding issues.

The only other applicants for the HD slot, Channel 4 and S4C, were unable to provide Ofcom with confirmation of their ability to launch a service within a defined timescale.

Any capacity within Multiplex B that is not reserved by OFCOM is available for the BBC to use. This brings forward by around two years the date when it was anticipated that further capacity on Multiplex B would revert to the control of the BBC Trust.

Sky and BT have signed a contract for the wholesale supply of Sky Sports 1 and Sky Sports 2 to BT. The deal means that BT customers will be able to sign up for the subscription channels from early July.  BT Vision customers will be able to view Sky Sports 1 and 2 from August 1, in time for the start of the Premier League season on August 14.

Further evidence of how competitive all this could get is in the story of how Sky subscribers could be convinced to stay as customers by the offer of free viewing via their gadgets and widgets.

There are different colour cables but on the whole many aerial engineers will use white or black cable depending on the colour of the house,to attach the cable to a wall you will need cable tacks which you should run all the way down at a good 300mm apart, this is to look tidy but most important that it does not fly around in the wind and get caught on anything. you will need good quality cable, double shielded 75 ohm cable is best, examples; made by webro and raydex though there are more manufactures coming on the market all the time. You will need connectors to connect to your aerial and also to your TV, the connectors you will need will depend on the aerial but some aerials will have connectors already on them.

An aerial can be put onto your chimney, the side of your building or in the loft. If you are going to install your aerial on the chimney it is best to use a lashing kit so that the aerial is stable and secure,but if you live in a low ground area you will need as much height as you can so a long pole will be needed.If it is going on the side of the building then you will need a bracket plus pole but this pole could be longer than the pole on the chimney,if it is to go into your loft you will need loft a bracket plus pole, one of the disadvantages of having an aerial in the loft is that the signal will not be as strong

You need a transmitter for your aerial so how do you know which one.To find your nearest go on-line and type in www.wolfbane.com/cgi-bin/tvd.exe?, on this site all you need to do is put your postcode in and a grid will come up with the transmitters nearest to you, it will also suggest an aerial (antenna).the position of the aerial(pol), group of aerial (gp) and many more details.

Aerial transmitter

What you watch on tv is received through your aerial from a transmitter. Around the country you will find over 1.100 and from 2008-2012 one by one the transmitters will be changing over to digital, your tv aerial is pointing to one of these transmitters so you need to know which one you are receiving from as this will determine the date you will be switching over and will also depend on how many channels you receive because of the signal strength. you may actually have a choice of transmitters as their signals may overlap but if you do change it could mean a change in how many channels you receive and also could lead to needing a new aerial as your current one may not have enough elements.

This is a very important decision as you need to know the signal strength and also which transmitter your on.

if you are in a recessed area this will reduce your field strength and you will need an aerial which is high gain, the aerial would probably be a 18 element or more. There are so many aerials on the market and you want to pick the right one.

to name a few you could use are:

YAGI – TCX UHF TV Aerials.

This is a Medium to high gain aerial for primary and secondary reception areas and is  Suitable for digital and analogue TV reception Designed to reduce noise pick-up Individually boxed.

High Gain – DX8 UHF TV Aerials.

This aerial is designed for digital  transmissions High forward gain, increased signal level fringe reception Impulse noise reduction – impedance matching balun Narrow acceptance angle – reduces multi-path signals.

Extra Gain – XG UHF TV Aerials.

this aerial is packed with features to improve reception of digital TV Full range for local through to fringe reception areas, its unique design increases signal strength and themassive reflector reduces noise pick-up.

FM & DAB Radio.

This range includes Omni-directional or high gain directional Unique Trumatch dipole on directional aerials Fold down into compact pack Easy assembly.