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Freeview reception - all about aerials

Your ability to receive all the Freeview transmissions depends on the suitability of aerial: the design style, "group" and its physical location.

Your ability to receive all the Freeview transmissions depends
published on UK Free TV

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.



Television sets?
What connections are used from set top box to TV (such as SCART) ?1
If you have several TVs at home do you need separate decoders for each set or is2
My TV is NICAM, does that mean I have digital TV?3
Can I use a Freeview box if there is no SCART connector on my TV?4
My video doesn't work with my digital TV box, help!5
In this section
Loft aerials1
Do I need to buy a booster?2
How to receive Freeview on your PC3
Indoor aerials4
Whole house digital TV5
Connecting it all up6

Comments
Friday, 13 February 2015
MikeP
7:29 PM

John Luke

It is unlikely to improve reception if it has the same number of elements as your existing aerial. And it may not be suitable for reception in the near future if the suggested frequency changes are implimented.

The ideal would normally be a log-periodic with at least the same inherent gain as your current aerial as that has the ability to receive the current transmissions and those that may become available in the future.

What is the reason for asking? Do you have reception problems? Remember that sometimes too much signal can be as bad as too little, if you're close to Sutton Coldfield that may be a factor. Ideally we would need a post code, or that of a close-by shop, so that your reception conditions can be assessed by others contributing to this website.

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MikeP's 660 posts Gold Gold xx
Thursday, 19 February 2015
J
John Luke
11:29 PM

Mike P:
Thanks for your reply. We live a long way away from Sutton Coldfield, in the folds of the Cotswold hills postcode GL66PA, but the only terrestrial reception, though weak, is from that transmitter. After switchover the reception improved with good reception except in some meteorological conditions (BBC2 had previously often been snowy with analogue).

The old aerial (presumably Group B?) died a few weeks ago after c. 30 years use. It had 15 cross (X) shaped elements (ie 60 element sections) plus twin reflectors with a c. 2metres long beam
.
The new aerial is a wideband which looks very similar to the Wolsey LTE HG 10 with double looped elements. It is much shorter with larger reflectors. However we cannot receive unpixelated any of the BBC channels.

I was wondering therefore whether installing a wideband aerial had led to the poorer reception?

John

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John Luke's 3 posts xx
Friday, 20 February 2015
Dave Lindsay
12:17 AM

John Luke: At switchover the Stroud relay transmitter became co-channel with Sutton Coldfield's PSBs albeit that it's vertically polarised. Therefore I would suggest that this could be the cause of your woes.

Unfortunately it would seem your only other option is Ridge Hill. If you find that the lower-powered COM channels are not good enough then you may be able to combine Sutton Coldfield's COMs with Ridge Hill's PSBs.

As Ridge Hill is all Group A, a wideband yagi isn't the best thing to use:

Rowridge Transmitter

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Dave Lindsay's 5,496 posts Platinum Platinum xx
J
John Luke
1:24 PM

Dave Lindsay:
Hi Dave,
Thanks for your help. Unfortunately we get no reception from Ridge Hill even though it is much closer than Sutton Coldfield (SC). There is also nothing from the Stroud relay transmitter which is very close but just like Ridge Hill there is a big hill in direct line of sight. Until very recently we have had perfectly acceptable reception from the old aerial directed at SC. I think we are therefore stuck with SC. My thoughts are to take down the new wideband Wolsey HG10 and replace it by a group B aerial such as the Antiference XG9BK. Any thoughts?

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John Luke's 3 posts xx
Dave Lindsay
7:12 PM

John Luke: I suggest that if it's a yagi aerial then go for Group K. With the Group T "LTE" aerial you have gain on channels 49 through to 60 which isn't necessary. The wider the band of a yagi the more of a compromise it is. I say Group K because SC could use channels in the 20s in future.

See:

TV Aerial Tests

Gain (curves), Again

I write on here as a technical bod rather than an installer, so which it should be, I'm not sure. Or a log and amplifier maybe??

Here's a terrain plot showing two obstructions:


Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location


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