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aerial' for analogue reception, but as they are generally unsuitable for Freeview reception, they have now generally been replaced by the Yagi type.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?
Sunday, 11 September 2011
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alan8:12 PM
West Wickham
My thanks to all who have very kindly offered advice-it is very much appreciated.
I will let you know how I get on.
Alan
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alan's: mapA's Freeview map terrainA's terrain plot wavesA's frequency data A's Freeview Detailed Coverage
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Steve P8:19 PM
alan - what do you use for TV receptioon at the moment? Have you tried it for digital?
You already have a very powerful signal
UK digital TV reception predictor
and may just need a set top - or a bit of wire in the aerial socket of the TV.
At SE249QP - similar distance from CP - I need NOTHING for analogue. Not tried digital there .
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Tuesday, 13 September 2011
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Des Collier8:05 PM
Geoff:- I use a 40 element log-periodic aerial,obtained from Aerials & tv,& it works extremely well,especailly if you require a wideband aerial,that has very directional & good interference rejection.
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Wednesday, 14 September 2011
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Matt10:21 PM
Godalming
Log 40s can be very good, but they have nowhere near enough gain where I live. I need a Unix 100B to get guildford because of its very strict broadcasting directions.
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Matt's: mapM's Freeview map terrainM's terrain plot wavesM's frequency data M's Freeview Detailed Coverage
Thursday, 15 September 2011
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steve.t9:12 PM
Dartford
hi am in dartford have low signal strength on itv,channel 4 and some others so bought a Mux Magician ultra high gain group w aerial because it said it was good for bad digital reception.when looking online for a direction to point it came across this site,saying it would be better to have a group a because it may avoid inteferance from other masts.is this right because it would be agro trying to send it back but dont want to put it up if its gonna make things worse.thanks for any help.
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steve.t's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
Friday, 16 September 2011
steve.t: As long as the aerial is on the roof it doesn't matter at your location if you use a wideband or group A aerial.
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steve.t5:17 PM
Dartford
cheers thanks very much for your help
link to this comment |
steve.t's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
Saturday, 17 September 2011
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Steve P7:36 AM
... UK digital TV reception predictor
263 degrees (ie just south of West, which is 270 degrees) it says above.
But anyway can't you SEE Crystal Palace?
Surprised you have a problem with that 61dBuV/m signal. What are you using now? Will you recable as well as new aerial?
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Mike O'Pray5:35 PM
I receive my programmes from Sandy Heath and have previously mentioned poor reception from Film4 and ITV4. I think I recall getting a reply to the effect that in Aug/Sept the further re-tuning that was required on 31 Aug and 14 Sept should transfer the two channels mentioned above to a stronger group and reception might then be fine
Well I did both re-tunes and the two channels are still basically unwatchable for almost all of the time. It may be that the Aug/Sept retunes have still not transferred these two channels to the max signal strength of course
Will the re-tune in Nov cure the problem or can I now assume that my standard aerial needs upgradng and without an aerial change my reception of these two channels will remain probematical?
I have the standard aerial on the roof and it is pointed at Sandy Heath.
Thanks
Mike O'Pray
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Des Collier7:20 PM
Logs certainly don't have as much gain as a standard aerial,but instead of using a wideband aerial,e.g for belmont,you could diplex a group A with a group C/D to get all the multiplexes.
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