Freeview reception - all about aerials
Updated 8th January 2014.
Your ability of receive all the Freeview transmissions depends on the suitability of aerial
- the design style,
- the "group", and
- its physical location.
Standard type - Yagi aerial
The standard type of TV aerial is known as the Yagi aerial. It is mounted on a pole, and consists of a rod with a reflector (shown green) at the back and many spiky elements (in grey) at the front. The connecting cable connects to the element nearest the reflector, known as the driver (shown in blue).
These Yagi aerials are directional and so pick up signals best from a transmitter that the rod points towards. The more elements the aerial has, the better it picks up a signal and becomes more directional.
A standard-type aerial is all that is required for digital TV reception in most places. These antennae have between 10 and 18 elements and a single reflector. These are recommended for new installations for good digital television reception, but will more often than not function perfectly in good reception areas.
Typically these aerials are designed to receive only some transmission frequencies - see "groups" below.
High Gain aerials
These aerials are designed for poor digital reception areas, and have two reflectors. For maximum signal strength, some digital high gain aerials have up to 100 elements. Since the switchover to digital-only transmissions back in October 2012, most UK households now have good quality digital TV signals.
A more expensive aerial is only required where the signal strength is low, but can often provide the whole Freeview reception where it might otherwise be impossible.
The CAI (that represents aerial installers) has four standards for digital TV aerials. The highest standard "1" is for homes on the fringes of coverage areas, intermediate standard "2" is suitable for use within the coverage area; minimum standard "3" is for good coverage conditions.
These aerials can be either wideband, or receive only selected frequencies - see "groups" below.
Grid
You may haved used a 'Grid aerial' for analogue reception, but as they are generally unsuitable for Freeview reception, they have now generally been replaced by the Yagi type. However in some places a Grid aerial installation may work for Freeview: otherwise replace with a standard Yagi aerial.
Indoor
Indoor aerials are generally not suitable for Freeview reception. In areas of good signal strength it is often possible to receive some transmissions. Even where an aerial works, people often find that may get interruptions to their viewing (or recording).Loft mounted
Loft mounted arrivals are not generally recommended for Freeview reception, as the roof tiles and plumbing will degrade the signal. Some compensation for this loss of signal can be made by using satellite-grade cable to connect the set top box to the aerial.Positioning
The best position for a TV aerial is mounted outdoors, as high from the ground as possible, pointing directly at the transmitter. The signal can be blocked by hills and tall buildings. It should be positioned away from any other aerials.Horizontal or vertical?
The transmitter will either use vertical mode which requires the elements of your aerial to be up-down, or horizontal mode which requires them to be level with the ground.Groups
Both analogue and digital television is transmitted the same group of transmission frequencies (known as channel 21 through to 60). A coloured marking on the aerial shows the group.To create the best possible analogue picture, TV transmissions from adjacent transmitters have been designated to several different groups of frequencies. By using an aerial that receives only the channels in the correct group, the analogue picture can be kept free from interference.
To receive Freeview transmissions from the same transmitter it has been sometimes necessary to use frequencies that are not part of the transmitter's normal group. When this has occurred, the aerial will need to be replaced with a "wideband" aerial (also known as group W) - one that covers every group.
As Ofcom is planning to move the TV frequencies again - perhaps as soon as 2018 - it may be wise to use a wideband aerial if you can to ensure you can keep viewing Freeview for many years to come.
Help with Television sets?
Friday, 24 August 2012
john hunt: Perhaps the issue is that the TV is tuned to the wrong transmitter; maybe it is tuned to a transmitter other than the one the aerial faces.
At your location, there would appear to be two main possibilities:
- Winterborne Stickland which is at 251 degrees - aerial will be vertical (elements up/down)
- Rowridge on the Isle of Wight which is at 110 degrees. Aerials can be horizontal or vertical, but will probably be horizontal as the vertical component has only been added earlier this year at switchover. New aerials would probably be best vertical for Rowridge.
If your aerial faces Winterborne Stickland, then check that the receiver hasn't tuned itself to the signals from Rowridge instead.
To do this, bring up the signal strength screen whilst on BBC One and it will say that it is tuned to UHF channel 46 (equivalent to frequency) for Winterborne Stickland and C24 (channel 24) for Rowridge.
Do the same for ITV1. It is C43 from Winterborne Stickland and C27 from Rowridge.
If your TV receives HD channels, then go to BBC One HD and bring up the signal strength screen and it should say that it is tuned to C40 for Winterborne Stickland and C21 for Rowridge.
If your aerial faces Winterborne Stickland and you find that it is tuned to Rowridge, then run the automatic tuning scan with the aerial unplugged for the first 30% to miss out scanning of the Rowridge channels. Once you have done this, confirm that it is tuned to Winterborne Stickland by following the procedure above.
Winterborne Stickland does not broadcast all Freeview channels it is a Public Service Broadcaster (PSB) transmitter only. PSB services are BBC TV and radio, ITV1, ITV1+1, ITV2, Channel 4, Channel 4+1, E4, More 4, Channel 5 and the four HD services.
The other services (ITV3, Pick TV, Yesterday, Film 4, Dave etc) are known as the Commercial (COM) ones and do not have as a comprehensive coverage as the PSBs as the smaller transmitters like Winterborne Stickland don't carry them.
Thus, if your aerial faces Winterborne Stickland and you receive COM channels, then you can only be receiving them from a transmitter off-beam of your aerial which is why poor reception may ensue.
If your aerial is facing Winterborne Stickland and you carried out the unplugging aerial trick to get it to tune correctly, then you will be missing COM channels. As I say, the best you can do is tune to Rowridge's COM channels. If your TV has manual tuning, then you need to go through and do a manual tune/scan on C25, C22 and C28.
If your aerial faces Winterborne Stickland and you decide to have it replaced with one on Rowridge to give you the full complement of channels, then it might need replacing if it is a "Group B" one (yellow tip - although it could be faded and difficult to make out from ground level). Rowridge aerials are now best vertical as COM channels aren't as strong horizontally.
-----
For a full list of Freeview channels after switchover, see:
DTG :: DTT Services by Multiplex
This shows which services are carried on which multiplex (signal), of which there are six in total:
PSB1: BBCA (BBC One, BBC Two etc)
PSB2: D3&4 (ITV1, C4, C5 etc)
PSB3: BBCB (BBC One HD, BBC HD, ITV1 HD, Channel 4 HD)
COM4: SDN (ITV3 etc)
COM5: ArqA (Pick TV etc)
COM6: ArqB (Yesterday etc)
To re-itterate, Winterborne Stickland doesn't carry any of those within the COM groups it is PSB only.
link to this comment |
J
john hunt1:58 PM
Blandford Forum
I THANK YOU FOR THE INFORMATION,I will now go and apply some of this and see how we get on
J&J
link to this comment |
john's: mapJ's Freeview map terrainJ's terrain plot wavesJ's frequency data J's Freeview Detailed Coverage
A
adrian whittemore2:16 PM
thanks for help posted - useful -seems at least part of my problen is a faulty downlead, should be getting good results off of crystal palace when i change that!
link to this comment |
S
Stephen P7:40 PM
john hunt - you may find the pages here devoted to your local transmitters useful - eg for local issues, and also ofr the info on channels on each multiplex. Which will let you work out what you are watching.
This
UK digital TV reception predictor
shows you have a fairly strong signal from winterbourne and a weaker but usable one from Rowridge. Is your AE H or V? And pointing East or West?
Are other locals same way?
Your man who charged you £84 should come back and make it all work (for no extra!). Confused about TWO boxes. How many rooms served?
link to this comment |
J
john hunt11:39 PM
Blandford Forum
my AE is Horizontal and pointing west as other local aerials
link to this comment |
john's: mapJ's Freeview map terrainJ's terrain plot wavesJ's frequency data J's Freeview Detailed Coverage
S
Stephen P11:51 PM
jh - you might do better with it vertical and/or pointing ESE.
See
UK digital TV reception predictor
Rowridge (Isle Of Wight, England) full-Freeview transmitter | ukfree.tv - 10 years of independent, free digital TV advice
The man you have paid really should be able to get you a good wirking signal on all channels
link to this comment |
Saturday, 25 August 2012
J
john hunt12:14 AM
Blandford Forum
Sorry..it is pointing EAST my error.I may consider a new vertical aerial Jh.I will follow it up in the morning.thanks
link to this comment |
john's: mapJ's Freeview map terrainJ's terrain plot wavesJ's frequency data J's Freeview Detailed Coverage
S
Stephen P9:22 AM
Just turning it vertical should improve.
Is it on a roof?
link to this comment |
john hunt: As Stephen P says, turning it vertical should be expected to improve reception.
Generally speaking, there is no need for aerials on Rowridge (which yours is) to be replaced after switchover. The only thing that viewers might benefit from is changing from horizontal to vertical polarisation.
link to this comment |
john hunt: I use the words "expected" and "generally speaking" because there's no absolute guarantee. Even the experts say that TV reception can be a black art!
All the best for getting your issue sorted.
link to this comment |
Select more comments
Your comment please