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aerial' for analogue reception, but as they are generally unsuitable for Freeview reception, they have now generally been replaced by the Yagi type.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?
Wednesday, 4 January 2012
K
KMJ,Derby7:11 PM
Sarah: How do the TVs receive the analogue channels at present? You will have to purchase a freeview box for each TV if you wish to continue viewing broadcast channels, but if you are in a strong signal area and currently have a good clear analogue picture it is possible that your freeview boxes will work ok using whatever aerial you currently have. However, if you are putting up with a grainy picture which changes as people walk about, then you will need a better aerial, at least in the loft in order to deliver a stable signal to each TV.
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Sarah7:34 PM
London
KMJ,Derby : We use fairly cheap indoor aerials and yes they do get a bit snowy but they are only very old style portable TV's (they don't have scart connections)
i have one amplified aerial on a freeview TV downstairs but half the channels are missing.
So basically if i want the TV's upstairs to work i'm gonna have pay a small fortune!!!
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Sarah's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
Sarah: At 5.7 miles from Crystal Palace with clear line of sight to the transmitter (at roof level, assuming no local obstruction), you might be lucky.
The transmitter is to your west and therefore I would suggest that the signal is going to be best at that side of the house. You might have to experiment siting your aerial in various places in the room. An aerial extension lead might be helpful and you may have one or more of them from video recorders or similar devices (what you used to connect the video to the TV).
You might find that putting the aerial on the top of a wardrobe or shelves might help. Also, don't assume that higher is better; often it is but sometimes inside that doesn't hold good, so you've really got to experiment.
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Sarah: The digital signal from Crystal Palace is weaker now than it will be after switchover in April. You could try your aerials with digital now, but if they don't work successfully, they might do after switchover. However, if they do work now, it's fair to assume that they are likely to work after.
One other thing you could do is, whilst you have analogue still available, do some experimentation to see what parts of the room the signal is good and where it's not so good. This might be helpful as the digital signals (after switchover) might be good in the same places that analogue is good now. If you do carry out this test, don't use Channel 5 because its signal is not from Crystal Palace.
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K
KMJ,Derby8:00 PM
Sarah: If the TVs have no scart socket you will have to search out a freeview box with an inbuilt RF modulator so that the output can be received via the aerial socket. Remember that the transmitter power is increased at switchover, so you might find that you are then able to receive all the channels downstairs using your amplified indoor aerial. Reception upstairs is usually better than downstairs and you are shown as being in a good reception area (albeit that predicted reception is based on using a roof aerial, with no local obstructions in the signal path) You could try a suitable freeview box on one of the TVs, then you will be in a better position to decide what you need to do.
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jb388:06 PM
Sarah: I would like to back up what Dave Lindsay has said, insomuch that its almost guaranteed that come next April 18th when Crystal Palace switches to high power (from 20Kw up to 200Kw) that when you presently manage to get what you do with the station on low power, then come April you are most likely to receive all channels with the minimum of effort even allowing for the fact that set top type aerials are not really recommended for Freeview reception.
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Sarah8:07 PM
London
Dave Lindsay: i will experiment. there are some large trees at the side of the house but it doesn't need to be perfect as there not the main TV's
Thanks for your help
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Sarah's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
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Sarah8:18 PM
London
jb38: i have freeview TV downstairs which does work with an amplified aerial but as i said half the channels are missing. so i will wait and how that responds before i decide what i
need to do.
Thank you everyone
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Sarah's: mapS's Freeview map terrainS's terrain plot wavesS's frequency data S's Freeview Detailed Coverage
Sarah: I have one of these Labgear set-top aerials:
Discontinued - Labgear Tristar ANR310 | digital tv aerials | indoor aerials | tv aerials | best tv aerial | indoor aerial Test Reports | summary report for the Labgear Tristar ANR310
I usually use a loft aerial, but I have sometimes used it on the first floor. I am 25 miles from Emley Moor and obtained good reception on digital channels before switchover. I have line of sight at roof level.
There can't be any guarantees, but I'd certainly give it a shot.
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J
jb389:05 PM
Sarah: Yes! best policy, at just under 6 miles from a 200Kw transmitter you might even suffer from the effects of an over powerful signal if you elaborate to much with your aerial system, this based on what you are getting at present, as many people located at that type of distance from a powerful transmitter find that they can even get reception with a short piece of wire pushed into the TV's or boxes aerial socket, not of course that I am advocating that being done!
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