Full Freeview on the Divis (Northern Ireland) transmitter
Brian Butterworth first published this on - UK Free TV
Google Streetview | Google map | Bing map | Google Earth | 54.607,-6.009 or 54°36'24"N 6°0'34"W | BT17 0NG |
The symbol shows the location of the Divis (Northern Ireland) transmitter which serves 440,000 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.
This transmitter has no current reported problems
The BBC and Digital UK report there are no faults or engineering work on the Divis (Northern Ireland) transmitter._______
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 Divis 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 Divis transmitter?
BBC Newsline 0.6m homes 2.5%
from Belfast BT2 8HQ, 1,044km northeast (51°)
to BBC Northern Ireland region - 46 masts.
Are there any self-help relays?
Chapel Fields | Transposer | Central Belfast | 61 homes |
How will the Divis (Northern Ireland) transmission frequencies change over time?
1950s-80s | 1984-97 | 1997-98 | 1998-2012 | 2012-13 | 4 Mar 2020 | ||||
VHF | A K T | A K T | A K T | K T | W T | ||||
C1 | BBCtvwaves | ||||||||
C21 | C4waves | C4waves | C4waves | +D3+4 | D3+4 | ||||
C23 | SDN | SDN | |||||||
C24 | ITVwaves | ITVwaves | ITVwaves | BBCB | BBCB | ||||
C26 | ArqA | ArqA | |||||||
C27 | BBC2waves | BBC2waves | BBC2waves | BBCA | BBCA | ||||
C29 | ArqB | ||||||||
C30 | LBT | ||||||||
C31 | BBC1waves | BBC1waves | BBC1waves | ||||||
C33 | com7 | ||||||||
C34 | com8 | ||||||||
C36 | _local | ||||||||
C48 | NIMM | NIMM | |||||||
C55tv_off | com7tv_off | ||||||||
C56tv_off | COM8tv_off |
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 10 Oct 12 and 24 Oct 12.
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 | |
com8 | (-16dB) 12.7kW | |
com7 | (-16.1dB) 12.4kW | |
LBT | (-20dB) 5kW | |
Mux 1*, Mux 2*, Mux A*, Mux B* | (-23.4dB) 2.3kW | |
Mux C* | (-24dB) 2kW | |
Mux D* | (-24.9dB) 1.6kW | |
NIMM | (-47dB) 10W |
Which companies have run the Channel 3 services in the Divis transmitter area
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Thursday, 8 November 2012
J
John Durrell9:04 AM
Coleraine
Many thanks to Mike Dimmick for his very detailed post. From what Mike has said it seems to me that the interaction of the TV and external i-Can receiver is the issue. The Sharp Aquos TV was bought in 2007 and plays blurays perfectly well in 1080p but I suppose it is getting a pure signal. From what Mike has said the broadcast signal is slightly different and I imagine that the technology in the TV cannot cope with this. The answer seems to be a new TV when this one 'dies'. Thanks agin Mike for all your help. I can now stop worrying about aerials.
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John's: mapJ's Freeview map terrainJ's terrain plot wavesJ's frequency data J's Freeview Detailed Coverage
Keith: Divis uses only Group A channels and wideband yagi aerials are less efficient on those channels.
Use a Group A aerial:
Rowridge Transmitter
Digital TV Transmitters
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P
Peter Henderson1:12 PM
Keith: I'd also think about getting the aerial mounted outside on the chimney. It should make quite a bit of a difference.
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D
David6:08 PM
Keith: My mother lives in Blackrock and is picking up all freeview muxes from Divis on a chimney mounted group A aerial.
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Friday, 9 November 2012
K
Keith5:15 AM
Thanks guys. I'll have to get myself a group a aerial.
Another question, to get the saorview signal from Claremont Carn I will need a c/d group aerial, is this correct or will I be able to continue using my wideband aerial (which is picking up soarview perfectly now) and how do I wire the 2 aerials into 1 coax cable??
Thanks again for your help.
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Keith: The sensitivity (gain) of an aerial isn't the same across all UHF channels/frequencies. For yagi aerials, the shape of the curve is broadly the same. See here for examples that illustrate my point:
Gain (curves), Again
The gain of wideband yagi aerials on Group A channels is much lower than C/D ones. That is why there is no such thing as a high gain wideband aerial that has "high" gain on Group A channels.
More gain in one direction is simply at the expense of more "loss" in others. So the "beam" of a higher gain aerial is narrower.
If your wideband aerial is sufficient for Clermont Carn, then there is no reason not to continue using it. The reason for suggesting use of a Group A aerial for Divis is because of the lower gain of the wideband aerial on its channels and the poor reception you are experiencing.
You need a diplexer to combine the two feeds:
Online TV Splitters, Amps & Diplexers sales
For Divis and Clermont Carn, get a diplexer that "splits" at C38. This will allow you to receive a multiplex from Divis on C36 should it ever come to fruitition.
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Saturday, 10 November 2012
M
MEM1:24 AM
Does anyone have any idea why I can get the RTE radio stations via Digital TV but not through my DAB radio?
I live in the Newry area, prior to DSO I could get a very weak signal from the RTE radio stations on my DAB set but it would never tune in. I would get a service not available message.
After the DSO I retuned my DAB radio in the hope of getting a better signal but I have now lost all the RTE channels.
I would appreciate any help thanks.
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MEM: Because the DAB signal and the TV signal are different signals. The TV switchover didn't mean any difference to DAB radio.
See:
Digital Radio Ireland » Can I get DAB
Maybe you need a directional aerial.
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C
Carl8:25 PM
Mem
DAB is and has been a disaster from the start as far as I'm aware it has been put on hold until the powers that be can work out what they will do with it.
I would stick to radio through tv at the moment.
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Sunday, 11 November 2012
M
MEM1:32 AM
Well I found out that Clermont Carn is broadcasting DAB at only 5kw. I believe the TV signal is broadcast at 160kw.
Don't think I would have any chance of getting a DAB signal at that level no matter what aerial I use.
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