Full Freeview on the Oxford (Oxfordshire, England) transmitter
Brian Butterworth first published this on - UK Free TV
Google Streetview | Google map | Bing map | Google Earth | 51.790,-1.179 or 51°47'25"N 1°10'46"W | OX3 9SS |
The symbol shows the location of the Oxford (Oxfordshire, England) transmitter which serves 410,000 homes. The bright green areas shown where the signal from this transmitter is strong, dark green areas are poorer signals. Those parts shown in yellow may have interference on the same frequency from other masts.
_______
Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
DTG-12 QSPK 8K 3/4 8.0Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Which Freeview channels does the Oxford transmitter broadcast?
If you have any kind of Freeview fault, follow this Freeview reset procedure first.Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
DTG-12 QSPK 8K 3/4 8.0Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Which BBC and ITV regional news can I watch from the Oxford transmitter?
BBC South (Oxford) Today 0.4m homes 1.6%
from Oxford OX2 7DW, 6km west-southwest (258°)
to BBC South (Oxford) region - 6 masts.
BBC South (Oxford) Today shares 50% content with Southampton service
ITV Meridian News 0.9m homes 3.4%
from Whiteley PO15 7AD, 102km south (182°)
to ITV Meridian/Central (Thames Valley) region - 15 masts.
Thames Valley opt-out from Meridian (South). All of lunch, weekend and 50% evening news is shared with all of Meridian+Oxford
How will the Oxford (Oxfordshire, England) transmission frequencies change over time?
1950s-80s | 1984-97 | 1997-98 | 1998-2011 | 2011-13 | 2013-18 | 2013-17 | 23 May 2018 | ||
VHF | C/D E | C/D E | C/D E | C/D E | C/D E T | W T | W T | ||
C2 | BBCtvwaves | ||||||||
C29 | SDN | ||||||||
C31 | com7 | com7 | |||||||
C37 | com8 | com8 | |||||||
C41 | BBCA | ||||||||
C44 | D3+4 | ||||||||
C46 | _local | ||||||||
C47 | BBCB | ||||||||
C49tv_off | C5waves | C5waves | |||||||
C50tv_off | SDN | SDN | |||||||
C51tv_off | LOX | LOX | |||||||
C53tv_off | C4waves | C4waves | C4waves | +BBCA | +BBCA | +BBCA | |||
C55tv_off | ArqB | ArqB | ArqB | com7tv_off | |||||
C56tv_off | COM8tv_off | ||||||||
C57tv_off | BBC1waves | BBC1waves | BBC1waves | BBCB | BBCB | BBCB | |||
C59tv_off | -ArqA | -ArqA | -ArqA | ||||||
C60tv_off | ITVwaves | ITVwaves | ITVwaves | -D3+4 | -D3+4 | -D3+4 | |||
C62 | SDN | ||||||||
C63 | BBC2waves | BBC2waves | BBC2waves |
tv_off Being removed from Freeview (for 5G use) after November 2020 / June 2022 - more
Table shows multiplexes names see this article;
green background for transmission frequencies
Notes: + and - denote 166kHz offset; aerial group are shown as A B C/D E K W T
waves denotes analogue; digital switchover was 14 Sep 11 and 28 Sep 11.
How do the old analogue and currrent digital signal levels compare?
Analogue 1-4 | 500kW | |
BBCA, D3+4, BBCB | (-7dB) 100kW | |
SDN, ARQA, ARQB | (-10dB) 50kW | |
Analogue 5 | (-11dB) 40kW | |
com8 | (-14.7dB) 17.1kW | |
com7 | (-14.8dB) 16.4kW | |
Mux 1*, Mux 2*, LOX | (-17dB) 10kW | |
Mux C*, Mux D* | (-18dB) 8kW | |
Mux A*, Mux B* | (-19.2dB) 6kW |
Which companies have run the Channel 3 services in the Oxford transmitter area
|
|
Tuesday, 4 October 2011
C
Chris.SE10:13 PM
Jonathan: Well done, the conclusion I was coming to.
link to this comment |
C
Chris.SE10:36 PM
OK, we need to correct some misunderstood information here -
1) The 3 PSB muxes at Oxford are on full power of 100Kw. The 3 COM muxes are on restricted power of 12.5Kw until April 2012.
2) Log periodic aerials DO have gain, usually not as high as some of the "high gain" aerials being used, unless they have built in amplifiers.
3) I would not recommend Jonathan change his aerial at this time due to his situation and variabilty of received signal.
4) You do NOT get "snow" on digital signals.
You either have an adequate quality signal - perfect picture, or not - no picture or pixelation if right on the "cliff edge". This can occur if the signal is weak or suffering interference.
You can also get picture/sound breakup or no apparent signal at a set/box with too strong a signal.
5) The only reliable way to be sure is with a proper signal strength meter.
Jonathan: does it not say what the aerial is on your receipt? You could always ring Oxford aerials and ask what they put in if the information is not there.
If we know, then it'll give an idea of what attenuation is needed and you can then see how stable the situation is over time and with the changing season. In the longer term changing the aerial may be an option.
You are correct to put the attenuator direct into the wall socket, in the middle of flying leads is not a good idea. The other place would be direct into the back of the set/box, perhaps the place for the fixed one you have ordered.
It wouldn't be a bad idea to check the connections at the back of the wall socket and anywhere else there may be connections between the socket and the aerial - did they put new coax in for you as well?
link to this comment |
C
Chris.SE11:06 PM
Richard: you are wrong. The signal has not been DELIBERATELY underpowered in the way you imply. The strength was determined by what was possible without causing undue interference to the existing analogue services and the other other digital services around the country (& abroad). Until DSO it was not possible to start increasing power and even where DSO has taken place not all MUXes at some transmitters are on full power yet until switch over in other regions has occurred.
Mendip and Oxford are two such examples where COM muxes have yet to go to full power.
Until transmitters and their antenna have been converted & DSO occurs, compromises have to be made. This can mean some locations can not get reliable signals. Indeed there were/are many areas that could not get any digital signal until local relay transmitters were switched over. Because of the work needed at the mast at Beckley to ensure good coverage after DSO, transmission has to be done from a temporary mast for a period of time. This was longer than originally planned because of the fire on the main mast. This also meant poorer signals for some.
If there is any criticism to be aimed it could well be at some dealers or aerial installers for not fully informing people or indeed for individuals not seeking adequate information, about the pre DSO situation and what may happen at DSO. To rely soley on Digital signals prior to DSO in an area that was suffering poor signals at the time was not sensible.
Even where people needed to purchase new equipment, for a TV set that didn't have an analogue tuner in addition to a digital one, such a set could have been fed a picture via a scart from a then existing VCR for example.
There have been minor hiccups as DSO has progressed, but generally speaking things have gone well especially in light of the mammoth undertaking and the need of the public to purchase new equipment and aerials.
link to this comment |
C
Chris.SE11:14 PM
Ralph: I've been beaten to informing you about Freesat. That said, West Swindon is one of the more problematic areas, but as you haven't provided a post code no one can advise how reliable a signal you might expect from Oxford now DSO has occurred or indeed Mendip.
The PSB muxes at both Mendip and Oxford are now on full power (100Kw each), but the COM muxes are on restricted power until March/April next year until other regions switch over.
link to this comment |
Wednesday, 5 October 2011
C
Chris.SE12:55 AM
Briantist: Hi Brian, could you update the Power info for the COM muxes, all restricted to 12.5Kw until April 2012. Thanks.
link to this comment |
M
Mike Dimmick12:56 AM
Chris.SE: A minor quibble, Oxford did not get a temporary mast to provide services while the main antenna was re-engineered. Instead the reserve antenna was used for all services. This is fitted *below* the FM radio broadcast aerials, which occupy a significant amount of space - the reserve is 55m lower down a 159m mast than the main antenna. This is the last resort should a future problem take out the main antenna or transmitters. The main antenna itself is designed in two halves and can be run on only one half, although (presumably) at reduced power. This redundancy is carried through to the combiner unit.
Unlike many sites, at Oxford, low-power DTT ran from the main antenna, plus an extra 'hat' on top of the old cylinder, with the possibility that a couple of multiplexes (1 and B) had an extra filler on the side of the mast, a little below the new reserve. That meant DTT was also quite seriously affected when the main aerial was being replaced.
link to this comment |
C
Chris.SE1:56 AM
As you say Mike, a minor quibble. I should have used the word Antenna instead of mast, but was hurriedly trying to keep the explanation simple in light of the lack of knowledge and other things to get on with ;)
link to this comment |
Just when you thought it was safe to go back in the water:):):). We are now getting breakup on ITV2 & ITV4 but not on any other channels. At switch over everything went swimmingly. SN34ST, any ideas.
link to this comment |
Robert's: mapR's Freeview map terrainR's terrain plot wavesR's frequency data R's Freeview Detailed Coverage
P
Paul8:31 AM
If moving the flylead changed reception and it is acting as an aerial, the screening is not very good. Perhaps you should try a new flylead.
link to this comment |
J
Jonathan8:57 AM
Oxford
Chris.SE, A reasonable question but I can't find the receipt for my aerial - I only have the email booking the visit which is how I know the fitter and date.
I have, however, applied a telescope to the problem, and can see the black junction box reasonably clearly. There seem to be four groups of text:
W 10 AB 1 CD/W
Channels 21/58
This junction box must be installed face down (or something to that effect)
CAII/AB 011
(I'm least certain about the top line where the text seemed slightly damaged).
It would appear to be a Yagi with 9 secondaries shaped like very flat Xs and two tilted reflectors.
link to this comment |
Jonathan's: mapJ's Freeview map terrainJ's terrain plot wavesJ's frequency data J's Freeview Detailed Coverage
Select more comments
Your comment please