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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 analogue TV reception in most places. These antennae have between 10 and 18 elements and a single reflector. These are not 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.
Digital High Gain
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. A more expensive aerial is only required where the signal strength is low, but can often provide 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 aerials have been used to improve analogue reception in poor reception areas. They are generally unsuitable for Freeview reception, however some installations may work. Otherwise replace with a digital high gain Yagi aerial.
Indoor aerials are generally not suitable for Freeview reception. In areas of good signal strength it is often possible to receive some transmissions.
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.
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.
Both analogue and digital television is transmitted the same group of transmission frequencies (known as channel 21 through to 68). 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.
Tracy,Liverpool.Is your aerial polarised horizontally facing Winter Hill or possibly Moel-Y-Parc,or is it polarised vertically facing a local relay in your vicinity.If you provide a full postcode as such,the true experts on here Briantist,Mike Dimmick,JB38,KMJ,Derby,etc,will provide ever valuable information and assistance to help your current situation as such.
Since the natiowide switch over which has been working ok - I have had a new aerial installed which is on the roof and is an all singing receptor - during the very windy period last week the picture and sound has frozen - is this to do with the windy conditions I have one tv which has digital installed and the other has a freeviewbox both connected to the same aerial. The free view box set is fine it is the digital tv that freezes any advice please or is it just instability due to the windy conditions.
I recently bought a HD STB and cannot seem to get the HD MUX by autotuning. The signal strength for the MUXs on 41,42,44,49 and 52 are around 35%, and the "Quality" (whatever that is) shows 95%.
When looking manually at BBCB MUX on 47, it initially showed no signal, but after a few minutes started to show about 50% signal strength, but zero Quality. (It also showed the following:
Tuner DBB-T2 BER:3.0E-3 C/N (dB): 24.2
682Mhz; 32k; 1/128:SISO,0)
To my amateur eye this looks like it can "see" C47 in HD.
Do you experts think this is a weak signal/aerial issue? I am currently using a wideband YAGI, SLX8 splitter booster that is installed maybe 15metres from the masthead. All cable is screened satellite stuff using F plugs. Would I benefit from a Group B aerial and a masthead amplifier?
Wimbledon starts tomorrow, and still no HD :(
I am at TN8 6PE, pointed at Tunbridge Wells (106 degree bearing) and very rarely have reception problems on the old SD STBs.
Furnace: You are indicated as being only 8 miles or so away from Tunbridge Wellstransmitter and as such might be receiving an excessively high level of signal, so for a test try by-passing the splitter booster, as an over the top signal will always affect HD before SD, the latter in many cases appearing as being perfectly OK.
Thanks for your thougts. I had read about the "overboosted signal" causing problems. My booster/splitter is a SLX8 and has a "full" output socket that passes through an unadulterated signal. Sadly this made no difference. As mentioned, the signal level on the MUXs to which I can successfully tune range from 20%-50%. I don't trust the readings to be precise, but would have though that would give a fair undication? In general the area I live in is known as being poor for DTT reception :(
I'm going to try a masthead amp today, and do some aerial wiggling. It currently points at 106 degrees which is slap bang at a huge oak tree 15 metres away.
We have a Yagi type aerial in HA4 post code, but suffer from sudden loss of reception (as last night @ 21.50h - ITV1, BBC fine still) and wonder if a digital high gain aerial is essential? An installer told us signal strength is good, but loss does occur. Our TV is the latest Sony.
Derek: A number of people have reported difficulty with signals from Crystal Palace and it is believed that this was due to the inversion effect, so there is probably nothing you can do.
Assuming no local obstructions like trees and buildings, you appear to have line of sight with the transmitter. Where that is the case, at 18 miles from a transmitter of the power of Crystal Palace, there should be no need for a high-gain aerial.
See this link for a plot of the terrain from you to CP:
Derek,Ruislip.If your Yagi aerial is directed at Crystal Palace main transmitter (an all group A mast) and is coloured red at its tips,then it is a group A aerial and the correct aerial for that mast concerned.There is no need to change to a so-called high gain aerial which most certainly will be a group W wideband type (coloured black at its tips),which have a poor performance generally on group A frequencies,especially more so on an all group A mast in a poor/marginal area as such.
Bizarre. As of yesterday I can now receive C47 carrying HD from T Wells transmitter, despite receiving no signal on this channel for the previous few days (see post a few lines up). Is it possible that the T Wells switchover (due to have completed on Jun 12) did not fully occur until Jun 27th?
Jan Gibson Saturday 30 June 2012 12:41PM Chelmsford
We have not been able to get ITV4 since the digital changeover in NOvember although we used to get it with a digi box before the switch. We have just bought a new Panasonic TV with HD and hoped we would be able to get ITV4 on this set as Freeview is incorporated in the set. Is it an aerial problem do you think - we have the same aerial as we've had for 40 years? (!) We have tried re-tuning but no luck.
ITV4 is carried on COM6 multiplex (known as "ArqB") which is on UHF channel (equivalent to frequency) 56 from Sudbury. Aerials fitted during the days of four-channel analogue (or even three-channel analogue !) will probably be less sensitive at frequencies used by the COMs. This may or may not prove to be an issue.
Assess which of the multiplexes are missing and which you have by referring to the above page and checking to see if the services on each are present.
If your receiver has manual tuning, then it is worth attempting to manually tune them. Depending on the design of the device, it may indicate whether there is a signal there, but just not strong enough.
The "C" numbers are UHF channel numbers that you need to input whilst on the manual tuning screen.
Your aerial will probably be a Group B one which means that it is most sensitive on the middle third of the band of frequencies used for TV. Sensitivity drops off outside this; it doesn't stop totally, but may be noticeably lower.
Whilst the Public Service channels (BBC, ITV1, C4 etc) are within Group B, the COMs are above it (top third known as Group C/D).
For this reason you may need your aerial replacing with a wideband one which is suitable for the whole band, or a Group E one which is the top two thirds of the band (which are Groups B and C/D combined).
Jan Gibson,Chelmsford.If your aerial is 40 years old dating back from 1971/2 and is coloured yellow at its tips,denoting a group B aerial then yes the aerial plus the co-ax cable and co-ax plug all need replacing.
A replacement group E Yagi 18E semi-wideband aerial coloured brown at its tips,plus new superior copper-copper black coloured co-ax cable and new brass co-ax aerial plug will vastly improve both your reception and viewing as such.
I get 30 channels where people nearby(1 mile away) get upto 100. I am told that i need to point to a different transmitter and get a new horizontal aerial. How can I check if this will work before spending money on a new aerial and fitting. I live in CT17 - currently point to Buckland transmitter - told to point to Hougham Transmitter. Question...If hougham is better why was it not pointing there in the first place? Any help would be appreciated.
cjh: It may be the case that Buckland (known as "Dover Town") is a better signal for you, which is why the aerial is directed to it.
In the days of four-channel analogue, all transmitters carried the same four channels. Main high power transmitters like those at Hougham (known as "Dover") cover large areas. Unfortunately their signals don't get everywhere, primarily owing to the terrain.
Because the ground slopes downwards towards the sea, reception from Dover is difficult to impossible, which is why the small "filler-in" relay transmitter at Buckland was installed. This is sited in a location where it can receive from Dover and where it can be "seen" by the area that has difficulty receiving from that main station and this is so that the area can receive from it.
It carried all four analogue channels and was therefore not inferior to the service offered by Dover.
Post switchover there is a two-tier terrestrial transmitter network. There are two types of broadcaster: Public Service ("PSB") and Commercial ("COM").
The four analogue channels had and still have a "Public Service" obligation (as does Channel 5) and they are now carried from all transmitters that carried four-channel analogue in the past, as this includes Dover Town.
However, the COMs don't have a "Public Service" obligation. They operate solely for their own benefit; i.e. to turn a profit. They transmit from 81 of the largest transmitters (largest by viewer population) and this includes Dover. This gives them coverage of 90% of the population.
They were asked if they wished to increase their coverage and they declined. For them to transmit from the 1,000 or so small relays like Dover Town would roughly double their cost of transmission whilst only adding 8.5% of the population to their potential viewer-bases.
When their objective is to get as many viewers as possible at lowest possible cost to show them advertising (which they sell), it's not hard to see why they don't wish to invest in the relays.
As Mark Fletcher says, a more specific location is necessary. Looking at the contour lines in the CT17 area, likelihood/difficulty of reception from the main Dover transmitter is likely to vary greatly owing to the slope.
the apartment we have moved into is wired up to recieve sky tv but we prefer virgin and had this installed the arial fitting in bedroom only recieves sky we only want to recieve ordinary tv in this room and dont want to run wires through walls is there any convertion connections on the market
My TV aerial recently came down and I need to replace it. One potential supplier has offered me a range of swanky new aerials whereas another has suggested putting back my existing one.
The existing one had been up since I moved in (making it over 10 years old at least) but it picked up freeview fine. The aerial supplies a single cable to my loft from which a booster splitter sends it to two TVs.
Can anyone advise me of a suitable replacement aerial (or indeed whether I should replace my existing one at all) and also explain whether/why I need to pay for additional TV points.
If the old aerial is of the age mentioned then I wouldn't really advise using it again because its bound to be suffering from elements of corrosion somewhere, as alloys always do.
I don't quite understand what you are meaning by why you should pay for extra TV points? or are you meaning the aerial person wanted to replace them? as if that's what was said then its unnecessary to do this if they were working OK.
This is a link where you will see the Log 40 referred to.
Thanks for the replies. I'll try to answer your questions as best I can.
Firstly, my current set up is this: a cable runs from the aerial into my loft and down into room 1 where a powered booster splits the signal.
One aerial company said all this needed taking out and that I'd need a second TV point installing, which would cost me. I don't know what he meant by "TV point" (my better half had this conversation, not I).
My point is: shouldn't my current set up work with a new aerial without the need for TV points?
Secondly, the current aerial came down because the lashing snapped.
Paul H: If the cable run from the loft down to the booster / splitter was working perfectly OK before the aerial problem occurred then it will still be, and as such does NOT require to be altered.
I suspect though that the aerial company is thinking along the lines of having the booster / splitter in the loft and running two feeds from the loft down to an outlet socket in each room, which of course ends up with exactly the same facilities as you presently have albeit "maybe" a little neater.
You could if you wish still use your old aerial, but speaking from an engineers viewpoint I wouldn't, and especially if it might even be older than the ten years that you know about, but of course the choice is entirely yours.
Actually, the chap was suggesting ripping the whole lot out and running a cable down the front of the house and drilling through the wall into the upper bedroom and lower lounge, fitting an extra TV point to allow this.
Paul H: Yes, in other words reinstalling everything in a somewhat more pleasing neater fashion, but though with the end result of this work only providing you with exactly the same facilities as you presently have as nothing will be be gained in the technical sense, not of course that this is required anyway if your reception was previously OK.
marion butler Friday 20 July 2012 9:55AM Berwick-upon-tweed
Over the last two weeks we have had periods where no freeview channels are showing on televisions in house. Then some channels are avaliable ( not itv/4/5.)then all return. At moment only a few are available. I have never had problems before and all 3 televisions have their own set top boxes. We are receiving signal from the Chathill transmitter in northumberland via rooftop aerial. How can i resolve this problem?
jb38: yes, the split sends the signal to a TV in the upper bedroom and lounge.
jb38 and Stephen P: thank you both for your help with this. I've had two totally different sets of advice from aerial fitters, so you've helped clear a few things up. I'm tempted to just get the fallen aerial put back up, given that it worked fine. However, I'm also tempted to use the opportunity to replace it just because it's old. A visual inspection suggests it's physically fine though.
Paul H: If its been visually inspected, and in particular inside the cover where the coax is connected onto the terminals, and no corrosion is seen nor is there any rust on the terminal screws then by all means just have the same aerial refitted, especially if as you say the reception was perfectly OK before the lashings failed.
If though at any time any further problems develop then the aerial referred to cannot really be beaten when used as a replacement where multi channel reception is involved, such as as applies with full service Freeview transmissions.
It is important to appreciate that aerials don't receive nothing outside of group, but that sensitivities drop off. For some example gain curves that illustrate this point, see Gain (curves), Again
You say that the current aerial works OK for all Freeview channels. If it is a C/D aerial, then it would appear that it is sufficiently sensitive on C29 at your location.
I raise this point not to sway you in any way if it is a C/D aerial, but just to make you aware. You may decide that as it is sufficiently sensitive, to have it put back up again. Or you may decide that "good practice" is to replace the C/D aerial with a wideband one.
Another possibility "may" be to install an aerial in the loft. You could perhaps do it yourself, although obviously there is no guarantee that you will get good reception in the loft.
Paul H: Log 40 aerials were made by a company called Philex / Labgear (same company) although there is another similar one made by Triax called a TL40F and another by a company called "Vision", but to be honest about it although I am not quite sure which brand is sold by ATV there is absolutely nothing to worry about when dealing with a company such as ATV.
However as far as you seeing white on the end of the aerial is concerned, white isn't an aerial group colour and what you see is likely to be a sun bleached out colour.
One small point that did cross my mind, not that it changes anything said by me, was your aerial mounted horizontally or vertically? as although Waltham is your best bet, but depending entirely on where you are located within the S.E. bottom end of Nottingham's NG2 area you might possibly have been receiving from the Nottingham transmitter. (Just asking out of curiosity)
Finally, should you have been studying these charts indicating aerial gain curves etc, I wouldn't let yourself be too influenced by what's seen on these as they represent the results obtained from aerials being tested under absolutely perfect conditions in an area the size of a football field, and with a signal source at one end that provides exactly the same level of output on Ch21 as it does on Ch68 (for accuracy of results) and with the aerial on test at the other, not exactly similar to the conditions applying in real life situations where multiplexes are mostly received at different levels from each other, so charts such as these are only handy for reference purposes.
Paul H: OK thanks, as that confirms that it was definitely Waltham that you were receiving from, me only being curious as although the Nottingham transmitter might appear to cover many areas including your own, in practice it doesn't very well hence why Waltham is used by many.
Using intervideo software on TV card in my desktop pc, picked up all main channels here in South Africa, but had crackling hissing sound with poor pickup on channel broadcast on UHF. This using a small aerial. Setup a Yagi type on the roof, pointing transmitter towards red & white painted large gantry aerials high up on hospital roof opposite as large trees and adjoining gable wall blocks transmitter in line with b/cast tower unviewable. Some channels very clear at times but affected by wind etc. Any help much apprec. Thx truly - RW Johannesbg.