All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Graham: Another possibility, which I touched upon, is to use Belmont as your main transmitter and have a separate set-top box purely for when you want to watch WestRunton for regional programming.
| link to this comment |
Tony Putner: Because the Commercial networks operate purely for profit and so choose those sites where they can cover the most viewers for least cost:
Londonderry (Northern Ireland) digital TV transmitter | ukfree.tv - 10 years of independent, free digital TV advice
The only thing you can do is investigate the possibility of receiving from another, full-service, transmitter.
| link to this comment |
Stuart: If you refer to the Electricity North West website (today's name for the local power distribution operator) and enter the postcode for the Glossop transmitter you will find that there is a power outage.
The Licence Fee is required by law to be paid by anyone who watches TV. It does not mean that any terrestrial signal is available.
The Licence Fee goes exclusively to the BBC, and as a Public Service broadcaster you have access to the BBC. It is the Commercial networks which do not wish to invest in Glossop and 1,000 similar transmitters because they do not consider they offer a worthwhile return.
It is ridiculous for anyone to suggest that they should pay less to the BBC because other, non-connected, operators choose not to serve a particular area. The issue is that they were allowed to pick and choose in the first place and that they were not mandated to mirror the Public Service networks.
The main transmitters have additional power supplies and emergency back-up generators to keep them running if there is a local power cut. I cannot agree with any suggestion that the small transmitters like Glossop should also have generators as this will add to cost and make the Licence Fee even higher!
| link to this comment |
According to ENWL faults page:
-----
Street name: HILLTOP
Postcode: SK13 7QJ
Fault type: Current Fault
Information: We have a local line fault affecting your area. We believe that this affects your property. This fault is due to damage to our equipment. Our engineers are aware of the problem. And a team is currently travelling to site. We expect to restore power to most customers by 21:00 hours today. We expect that customers close to the point of damage will be restored by 05:30 hours Tuesday. This is our best estimate at this time and may change as additional information becomes available. We apologize for any inconvenience caused by this interruption. This message was updated at 17:35 hours today.
Estimated time of restoration: 19/02/2013 05:30
Estimated time of restoration majority: 18/02/2013 21:00
-----
According to the map, there are no other faults in Glossop, so it appears as if it might be localised to Hilltop Road.
| link to this comment |
Al: Refer to Page 2. There was a power outage to the site which, according to the electricity distribution board's website was restored around two hours ago.
| link to this comment |
Anything, particularly within the first Fresnel zone (look it up), can affect reception, by refraction. I imagine that it's likely, particularly with the path being close to the ground, that there's quite a lot of clutter in the first Fresnel zone. Reflections can also affect reception because the reflected signal (the echo) is combined, or summed, with the main signal at the receiving aerial. The worst case extreme is that they are 180 degrees out of phase and therefore cancel each other out and you get nothing (I give the extreme merely to illustrate the point). Even the professionals say that RF is a black art.
Digital reception requires a good quality signal, where the digits are intact. A receiver requires the signal strength to be over a lower threshold, but not greater than an upper threshold, over which it becomes unstable. Basically, you need the strength to be within that window. As a matter of good practice, the objective is to have the signal strength sufficiently above the lower threshold such that natural variances in strength (owing to the weather etc.) aren't likely to mean it dipping under. By the same logic, there should be room for the signal strength to increase a bit without putting it OTT. The point is, therefore, that the picture is exactly the same irrespective of strength, and so the objective is *not* to get the strength as high as possible; it is to get the quality high and strength within the window.
The WF125 flylead isn't going to make much difference unless it happens to be sited within lots of interference. WF100 is more than sufficient for terrestrial frequencies, although WF125 does have a PE sheath, rather than PVC, which is better on the odd day that the sun does shine bright enough for the UV levels to be high.
You could try swapping the scart end-to-end. This scart system encompasses several different types signal and not all TVs support all types. RGB is best as all three colours go along separate wires, as opposed to being combined when sent and uncombined when received (which means quality isn't as good). If the set supports RGB, and I'm not sure how likely it might be to do so, then use RGB - it will need activating in the box's setup menu. You can, of course, take the digibox and scart to another TV and see how it works with that, and you may be able to try the old TV with a box in another room; this should give you an idea whether it's the box, the lead or the TV.
I'm not a professional, so can't say how much gap should be allowed between multiple aerials on a mast. However, I think that you should be looking to run all three TVs from a single aerial. It may be that you can do this using an unpowered splitter, or you may need some amplification, but you have some at your disposal anyway!
See A.T.V (Aerials And Television) TV Aerial, DAB Aerial, FM Aerial. for lots of information. For a start off, the old C/D aerial you have sounds like a crappy contract aerial; see A.T.V (Aerials And Television) TV Aerial, DAB Aerial, FM Aerial. aerials.html
The question you've got to ask is: is this a strength issue or a quality issue? I shall assume that you've looked at strength.
What could be the cause of poor quality, I ask myself. Remember I'm not a professional.
For a start off, the industrial buildings that are around you could be causing reflections. How were the analogue signals before they were switched off? Were there any clues such as ghosting which gradually got worse as more and more units were errected? Obviously before switchover the digital was weaker, so any reflections would also have been weaker and therefore have been less of an issue.
I can see your aerials on Streetview (June 2009) and they don't look very high, whilst your neighbours' are. Height isn't necessarily everything though. Could the single tree at the back be in close enough proximity to have an effect, I wonder?
There is a triangle-shaped clump of trees behind Cherry Tree Gardens and Highfield Road; might they be the cause of poor reception and could increasing the height of the aerial reduce their impact?
The thing with aerials is that the gain, in one direction, is at the expense of greater "loss" in other directions. So, generally, a higher gain focuses on a narrower "beam". This is an important point to bear in mind because you are interested in getting a good quality signal. Imagine you are the aerial looking out over a narrow angle and within that space there is a lot of clutter which is resulting in refracted (poor) light. Having a wider angle might allow you to see, on average, better quality light.
Now consider something like trees which are moving and so it follows that any effect of those trees must be changing. In some cases, these changes mean that the signal, at the receiving point, isn't usuable and so the picture breaks up.
If you have an amplifier, you can boost the strength if it isn't great enough, but you can't rebuild a poor quality signal; quality starts at the aerial. Even with a lower gain aerial, you may find that there is ample signal strength to feed one or more TVs.
See A.T.V (Aerials And Television) TV Aerial, DAB Aerial, FM Aerial. polardiagrams.html Log periodic aerials have a much neater polar response whereas yagis tend to have lobes. If the issue is poor quality caused by reflections, perhaps from the nearby industrial buildings, then these would appear to behind you and to the sides. A log may fare better at "rejecting" those reflections.
Read the bits on log aerials on the ATV site; the saying is "If you can use a log, use a log."
There are plenty of suppliers out there. I came across this one which sells a range of logs, each for less than £20 including delivery:
Aerials [Aerial Type: Uhf Log-periodic] > AerialSat.com
| link to this comment |
Coral Crossley: If you haven't retuned it then it would be expected to come back on again.
If you have retuned it and you are using a portable aerial then take it to the fixed (external) aerial in order to tune it in and then return it to its normal location.
Incidently, you may be able to receive all Freeview channels from Winter Hill. On Streetview I can see quite a few large Winter Hill aerials.
| link to this comment |
KNibz: Which transmitter does your aerial face? Have you confirmed that you are tuned to that transmitter and not another one?
There may be two possibilities at your location: the easiest being Kington, which carries only PSB channels and is on the hill on Brickyard Road, and Sutton Coldfield.
For each of the following, bring up the signal strength screen and ensure that it is tuned to the UHF channel of your chosen transmitter:
PSB1 | BBC One | Kington=C44 | Sutton Coldfield=C43
PSB2 | ITV | Kington=C41 | Sutton Coldfield=C46
PSB3 | BBC One HD | Kington=C47 | Sutton Coldfield=C40
COM4 | ITV3 | Sutton Coldfield=C42
COM5 | Pick TV | Sutton Coldfield=C45
COM6 | Film4 | Sutton Coldfield=C39
See this page for a list of services by multiplex (i.e. which ones belong to each PSB/COM):
DTG :: DTT Services by Multiplex
If your aerial is vertical (elements up/down) and directed to Kington and you have COM channels tuned in, then they are coming from elsewhere and so expect reception to be poor.
If your aerial is horizontal (elements flat) and directed to Sutton Coldfield, but your TV has tuned in Kington (for PSBs), then you need to correct this.
If you put the booster on in an effort to improve matters and you find that your TV is tuned incorrectly, then it might be a good idea to remove the booster.
| link to this comment |
David: I can't see why it would. Reading the explanation at the top of this page, BBC Two HD will be a simulcast of BBC Two England SD.
BBC One HD has a blank screen at times because there is only one variant for the whole of England, whereas BBC One SD has many. BBC Two SD has only one variant for England.
| link to this comment |
Monday 18 February 2013 5:05PM
Graham: See:
Online TV Splitters, Amps & Diplexers sales
A warning about the diplexer route: Belmont could in the future broadcast in the 31 to 37 range (but not West Runton) and this might be HD services.
Some on here have suggested that the COMs may, in the perhaps distant future, move to the 20s.
Again, separate feeds to your lounge might allow you to change it if needs be (or at least have them in an accessible location).