TV transmitters in NI post DSO

Peter Henderson

Does anyone have an up to date list of all the transmitters in NI post DSO ?

I've been wondering about this as it appears some of the analogue relays will not be repaced with digital ones. For example, I can't find any info. on small low power sites such as Bangor, Conlig, or Newtownards.

There's a fairly comprehensive analogue list on Mike Brown's website, MB21

The Cush

Peter Henderson wrote: »

Does anyone have an up to date list of all the transmitters in NI post DSO ?

Nothing official from Ofcom yet. NI is probably 2 years away from ASO, looking like Oct 2012 based on what the Minister said in the Dáil last week and the plan that North and South will switchover in conjunction with each other. I'd guess not everything has been finalised between the two jurisdictions yet so there may not be an up to date list of sites and their details yet. Also Ofcom indicated last year that NI would probably switchover in 1 day (like the Ch. Islands this Nov) unlike the current 14 day switchover process in the UK today.

sesswhat

Here are three results from the www.digitaluk.co.uk postcde checker which show that all three sites are included in the digital plans at this stage, if only for the two PSB muxes and the HD Mux.

Newtownards
Conlig
Bangor

Other transmitters are listed here.

Mike 1972

So the relays only wind up with Two SD ond One HD multiplex despite having four legacy frequencies available to them (plus additional scope for sharing frequencies with other nearby relays) ?

The Cush wrote: »

NI would probably switchover in 1 day (like the Ch. Islands this Nov) .

Thought CI were last on the list

The Cush

Mike 1972 wrote: »

So the relays only wind up with Two SD ond One HD multiplex despite having four legacy frequencies available to them (plus additional scope for sharing frequencies with other nearby relays) ?

Freeview lite, just like the other 1,000+ relays around the UK. The commercial multiplex operators were asked some years ago by Ofcom if the wanted capacity at the relay sites but did not take up the offer to cover the remaining 8-10% of the UK population. I guess the economics of it did not add up.

Mike 1972 wrote: »

Thought CI were last on the list

Channel Islands switchover date released

http://www.digitaluk.co.uk/transmitternetwork/transmitter_groups/fremontpoint

watty

TV3 beancounter relations.

lawhec

All main transmitters and relay stations in Northern Ireland (from the provisional list currently on Digital UK's website) will remain in service post-DSO in Northern Ireland. Unlike however in the south and across the Irish Sea, no new transmission sites are planned.

All transmitter and relay sites will not require an aerial switch come DSO to receive all services except Plumbridge, which is changing from Group C/D to Group B.

• Plumbridge is a small relay just outside the village of the same name, serving a part of the Glenelly Valley in the Sperrin Mountains that is shielded from the Strabane relay (there is another relay station a few miles east, funnily enough called "Glenelly Valley" near the village of Cranagh), RTÉ there, at least on VHF, can be received from Truskmore though I'm not sure how reliable UHF is. Anyway, the reason for such an awkward change is that presently two of the four frequencies used at Plumbridge lie above E62. The draft plan was to use a new frequency at E48 (along with E52 and E56) but now they plan to use E50 for the BBC-A multiplex, E46 for the UTV/C4 multiplex and E43 for the HD multiplex.
• The Derrygonnelly relay in Co. Fermanagh (serving the village of the same name) will become a Group B relay from a current Group E, but aerials shouldn't require changing from analogue installations.

Some relays will be changing to new frequencies from their current analogue broadcasts, but will stay in the same aerial group. Kilkeel and Gortnalee will be two that'll effect some viewers in the Republic. Also a few border relays were cleared for significantly higher powers than what they now have for analogue (up to 250W ERP) but I'd doubt they'll be on such powers eventually unless interference becomes a problem.

Ofcom a few years back did offer the owners of the SDN (Mux A) and Arqiva (Muxs C & D) additional frequencies to expand their coverage at some relay sites, but declined at the time to take them. That isn't to say that they won't take at least some of them up in future, but they won't at the moment at least. Off the top of my head, the transmission sites in Northern Ireland they were offered additional frequencies were...

• Black Mountain
• Carnmoney Hill
• Larne
• Newcastle
• Londonderry
• Strabane
• Camlough
• Kilkeel

If additional commercial multiplexes were to come on line at L/Derry, it'll go from a Group B (for analogue 1-4) to wideband.

Another additional problem will be concerning the coverage of the commercial multiplex from all three main sites. They will all be broadcasting at lower powers than the PSB multiplexes. At Divis, some places (particularly along the Down coast) may get co-channel interference with multiplexes on the same frequencies from Caldbeck. There shouldn't be many problems from Limavady though I did a postcode check back in the Summer on some locations in Derry city which showed a weakening of COM multiplex coverage due to a "reception change", but I'm not sure what this might be unless it concerns the Fanad relay in north Co. Donegal. At Brougher Mountain the COM multiplexes are being broadcast at 10db less power compared to the PSB multiplexes (at Divis and Limavady it's 3db), this is because the COM multiplexes are using the same frequencies as the PSB multiplex from Divis, but interference from Divis in the Brougher service area will still likely limit reception of the COM multiplexes further if the Digital UK reception predictor is to be believed. There's possible problems in store in Omagh, parts of mid & south Co. Tyrone and also south Co. Fermanagh. It looks like that could be a headache.

reboot

lawhec wrote: »

All main transmitters and relay stations in Northern Ireland (from the provisional list currently on Digital UK's website) will remain in service post-DSO in Northern Ireland. Unlike however in the south and across the Irish Sea, no new transmission sites are planned.

All transmitter and relay sites will not require an aerial switch come DSO to receive all services except Plumbridge, which is changing from Group C/D to Group B.

• Plumbridge is a small relay just outside the village of the same name, serving a part of the Glenelly Valley in the Sperrin Mountains that is shielded from the Strabane relay (there is another relay station a few miles east, funnily enough called "Glenelly Valley" near the village of Cranagh), RTÉ there, at least on VHF, can be received from Truskmore though I'm not sure how reliable UHF is. Anyway, the reason for such an awkward change is that presently two of the four frequencies used at Plumbridge lie above E62. The draft plan was to use a new frequency at E48 (along with E52 and E56) but now they plan to use E50 for the BBC-A multiplex, E46 for the UTV/C4 multiplex and E43 for the HD multiplex.
• The Derrygonnelly relay in Co. Fermanagh (serving the village of the same name) will become a Group B relay from a current Group E, but aerials shouldn't require changing from analogue installations.

Some relays will be changing to new frequencies from their current analogue broadcasts, but will stay in the same aerial group. Kilkeel and Gortnalee will be two that'll effect some viewers in the Republic. Also a few border relays were cleared for significantly higher powers than what they now have for analogue (up to 250W ERP) but I'd doubt they'll be on such powers eventually unless interference becomes a problem.

Ofcom a few years back did offer the owners of the SDN (Mux A) and Arqiva (Muxs C & D) additional frequencies to expand their coverage at some relay sites, but declined at the time to take them. That isn't to say that they won't take at least some of them up in future, but they won't at the moment at least. Off the top of my head, the transmission sites in Northern Ireland they were offered additional frequencies were...

• Black Mountain
• Carnmoney Hill
• Larne
• Newcastle
• Londonderry
• Strabane
• Camlough
• Kilkeel

If additional commercial multiplexes were to come on line at L/Derry, it'll go from a Group B (for analogue 1-4) to wideband.

Another additional problem will be concerning the coverage of the commercial multiplex from all three main sites. They will all be broadcasting at lower powers than the PSB multiplexes. At Divis, some places (particularly along the Down coast) may get co-channel interference with multiplexes on the same frequencies from Caldbeck. There shouldn't be many problems from Limavady though I did a postcode check back in the Summer on some locations in Derry city which showed a weakening of COM multiplex coverage due to a "reception change", but I'm not sure what this might be unless it concerns the Fanad relay in north Co. Donegal. At Brougher Mountain the COM multiplexes are being broadcast at 10db less power compared to the PSB multiplexes (at Divis and Limavady it's 3db), this is because the COM multiplexes are using the same frequencies as the PSB multiplex from Divis, but interference from Divis in the Brougher service area will still likely limit reception of the COM multiplexes further if the Digital UK reception predictor is to be believed. There's possible problems in store in Omagh, parts of mid & south Co. Tyrone and also south Co. Fermanagh. It looks like that could be a headache.

Might I humble suggest it is worth taking a look at Freeview(Lite) from Isle of Mann if you are near the South East coast,available on a piece of wet string,or in bad weather Group B (Yellow)Vertical Polarisation, wide band Amp in my case,channels 43 ITV and 46 BBC Soon to go HD .

lucernarian

I don't understand the purpose of changing Killowen mountain to DTT, I thought its sole function was to supply Kilkeel with a signal from Divis?? I would have expected satellite links would take over the function of Killowen Mountain when freeview reaches Kilkeel.

Also, the Kilkeel allocations are different on the Digital UK website compared to other websites I've seen or any Arquiva documents I've seen about DSO. Still in Group B however.

watty

They don't have satellite feeds for all of Freeview.

AFAIK backup feed on main UK sites is a second fibre or microwave link from a different direction.

Some existing "relays" may be fed via multi-hop terrestrial Microwave links. So it's possible (Guessing) that there would be a microwave link between Killowen and Kilkeel if there is LOS.

There have been experiments and trials, but mostly DTT "relays" from what I can see are not relays (Off air rebroadcast) but just mini-DTT sites fed by microwave or fibre carrying the MPEG-TS for each mux. Some might nowadays use MPEG_TS receivers and ASI to feed the DTT modulator via off air reception, but not old style "analogue" Frequency shifting (transposing), so it's possible Killkee will work of Killowen like that.

I don't think UK uses any sites fed entirely by Satellite like some countries have.

lucernarian

The Benagh relay is itself fed from Kilkeel which looks a bit tenuous. If they were going to use microwave links I'd be suprised if they went via such a high site but in any case, why would they not just turn Killowen Mountain into a microwave relay site instead of a UHF active deflector site when freeview comes around?

And this thread from over on Digitalspy suggests that some multiplexes at least have used off-air rebroadcasting: http://www.digitalspy.co.uk/forums/showthread.php?t=1007410

watty

As I explained "off-air" is possible. But it's not cheap and simple like Analogue is.

reslfj

watty wrote: »

.... There have been experiments and trials, but mostly DTT "relays" from what I can see are not relays (Off air rebroadcast) but just mini-DTT sites .....

Receivning and retransmitting on another channel is not very different from analogue relays.

Even some new sites are real relays. Skelmersdale is such a brand new relay, receiving from Winter Hill on ch 62H,59H and54H and retransmitting the three PSB muxes on ch 51V, 48V and 52V. The antennas are clearly seen on this picture (from MB21.co.uk)




For NI, Ofcom has a map of the TX sites with colour codes for each TX/DSO group.

The ERP will in most cases be less than the current analogue ERP of each relay.
Note that the channels 30-37 and 61-69 will not be used for DTT post DSO.

Lars

watty

You don't have a picture of what is INSIDE the box?

The Cush

reslfj wrote: »

Note that the channels 30-37 and 61-69 will not be used for DTT post DSO.

UHF Ch 31-37 could be used for 2 national DTT muxes from 97 sites using DVB-T2 post ASO as stated by Ofcom.

reslfj

The Cush wrote: »

UHF Ch 31-37 could be used for 2 national DTT muxes from 97 sites using DVB-T2 post ASO as stated by Ofcom.

But

• not for the 3 PSB UK-muxes and
• only if the Ofcom auction is won by a broadcast network operator.
• only if SFN operations is used.

In addition it may be possible to create one large SFN, if Fr,Be,Nl accepts the use of channel 36.

Lars

The Cush

reslfj wrote: »

The Cush wrote: »

reslfj wrote: »

Note that the channels 30-37 and 61-69 will not be used for DTT post DSO. Lars

UHF Ch 31-37 could be used for 2 national DTT muxes from 97 sites using DVB-T2 post ASO as stated by Ofcom.

But

• not for the 3 PSB UK-muxes and
• only if the Ofcom auction is won by a broadcast network operator.
• only if SFN operations is used.

In addition it may be possible to create one large SFN, if Fr,Be,Nl accepts the use of channel 36.

Lars

Ofcom has stated in its consultation the multiplexes could be used to migrate the existing DVT-T/MPEG-2 muxes to DVB-T2. Ofcom has made no final decision on this band yet as it will not be available until after ASO.

4.54 One or two new DTT multiplexes in the 600 MHz band operating with DVB-T2 and MPEG-4 would not only be able to offer a wide range of new services but could also facilitate the transition to these new technologies of existing multiplexes. Only one of the current DTT multiplexes operates with DVB-T2 and MPEG-4; the remaining five could convert to these new technologies but at the cost of disrupting their existing services. Their conversion to DVB-T2 and MPEG-4 could be accelerated directly by using the 600 MHz band or indirectly by the more widespread availability of appropriate receivers that would follow from the use of these technologies to develop new DTT services in the band.

http://stakeholders.ofcom.org.uk/consultations/600mhz_geographic/

reslfj

The Cush wrote: »

Ofcom has stated in its consultation the multiplexes could be used to migrate the existing DVT-T/MPEG-2 muxes to DVB-T2.

I did not - an do not now - read this as a promise of free spectrum, but rather an example of the potential use of this spectrum - after the DD auction.
I do however expect the 600MHz spectrum to fetch a low auction price and in the end be used for DTT - so there may not be any real problem.

If Ofcom in say a year will accelerate the T2 conversion the channels 31-34 (and to some extend 35+37 too) will be available in very large parts of the UK after the TV regions Anglia and Central has DSO'ed in 2011.
In fact channel 63-65 (and even 66-69) will be available until well into 2013 in most places.

But with the financial problems of today ???????

Lars

reslfj

watty wrote: »

You don't have a picture of what is INSIDE the box?

No. But take a look at this Granada DSO info or this Llanddona info. Some few relays are linefeed.

I think it is fair to assume the rest are rebroadcast 'off air' ?

Lars

Sam Russell

Interesting, Winter Hill has 70 relays, that is more than the whole of the Irish DTT service.

Peter Henderson

Just found this over at UKfree.TV,the whole list of transmitters and their switchover dates in NI:

http://www.ukfree.tv/closedown.php

Can't see any anomalies.

Wonder if there's going to be complaints with the fact that NI's second city is going to have a transmitter that's Freeview Lite in nature ? Or do most people in Derry City receive their signals from Limavady ? I wonder will installers use the Londonderry transmitter even if Limivady is available ? Are people even aware as to what freeview Lite is ?

The Cush

Peter Henderson wrote: »

Just found this over at UKfree.TV,the whole list of transmitters and their switchover dates in NI:

http://www.ukfree.tv/closedown.php

I'd take those 2013 dates with a large pinch of salt. According to the Minister last week we're switching off analogue by Oct 2012 and the plan is to switchoff in conjunction with NI.

Mike 1972

Peter Henderson wrote: »

Or do most people in Derry City receive their signals from Limavady ? I wonder will installers use the Londonderry transmitter even if Limivady is available ?

Dont know Derry that well but I daresay that recently installed aerials would point at the Londonderry TX (I gather its roughly in the same direction as RTE's Holywell hill TX) whereas much older installations would be pointed towards Limavady (Seeing as how its been around that longer). What part of the city (given that its hilly in places) one is in and whether one is more interested in having full UK Freeview than RTE (although a second aerial and a diplexer will probably get both) are probably factors as well.

Peter Henderson wrote: »

Wonder if there's going to be complaints with the fact that NI's second city is going to have a transmitter that's Freeview Lite in nature ?

Probably but then the situation in parts of NI's first city reliant on Carnmoney hill is just as bad (and in many places RTE isint quite as readily available to compensate)

reslfj

The Cush wrote: »

Peter Henderson wrote: »

Just found this over at UKfree.

I'd take those 2013 dates with a large pinch of salt. .

UKfree is a private site and its info is often not very reliable. Brian made the list as his own best estimate well before DSO started in the UK.

There are not official NI dates yet - just the aim at 'just after the Olympics' (or October 2012).

Use the official site http://www.digitaluk.co.uk/ for information - most of it is valid. For NI DSO is 2 years into the future and a lot can change. It is eg. likely that clearing the 800 MHz band will be an integrated part of such a late DSO.

Lars

The Cush

reslfj wrote: »

For NI DSO is 2 years into the future and a lot can change. It is eg. likely that clearing the 800 MHz band will be an integrated part of such a late DSO.

Ireland's Digital Dividend spectrum is now expected to be available to mobile operators from early 2013 with ASO in Oct 2012.

Peter Henderson

but then the situation in parts of NI's first city reliant on Carnmoney hill is just as bad

Indeed Mike, I just wonder how many people around here realize that they're going to be missing over half their channels becuse their TV aerial points towards Carnmoney Hill instead of Divis ?

Freeview reception from divis in Jordanstown isn't bad for about 98% of the time, and only suffers when there's a lift on. Post DSO, I reckon it'll be perfect from Divis.

Still, I suppose a lot of people wont even be aware of that fact and perfect signals from Channel 5 and News 24 might be all they could ever want.

The March 2013 date does seem an awfully long way off though. I will assume the 2012 date (October) on Digital UK's website is a more accurate one. After Christmas we'll be talking about "later next year".

Another problem around here will be when clermont Cairn turn off their analogue signals. I wonder how many viewers realize they'll need an Mpeg 4 receiver to continue viewing ?

The Cush

Peter Henderson wrote: »

Another problem around here will be when clermont Cairn turn off their analogue signals. I wonder how many viewers realize they'll need an Mpeg 4 receiver to continue viewing ?

A freeview-HD receiver will be required to receive the freeview-HD channels, which will be MPEG-4 compatible and so should receive the Irish channels also. Killing two birds the one ... etc.

For example Black Briar has been posting today about his new freeview-HD TV (like a kid with a new toy and why not ) which is receiving both the Irish DTT tests and freeview.
http://www.boards.ie/vbulletin/showthread.php?p=68362389#post68362389
http://www.boards.ie/vbulletin/showthread.php?p=68362426#post68362426
http://www.boards.ie/vbulletin/showthread.php?p=68362788#post68362788

lawhec

reboot wrote: »

Might I humble suggest it is worth taking a look at Freeview(Lite) from Isle of Mann if you are near the South East coast,available on a piece of wet string,or in bad weather Group B (Yellow)Vertical Polarisation, wide band Amp in my case,channels 43 ITV and 46 BBC Soon to go HD .

Of course, parts of the Co. Down and Co. Antrim coasts might be able to get services from Britain and IoM TX's the same way cross-border transmissions carry in Ireland.

lawhec

To_be_confirmed wrote: »

I don't understand the purpose of changing Killowen mountain to DTT, I thought its sole function was to supply Kilkeel with a signal from Divis?? I would have expected satellite links would take over the function of Killowen Mountain when freeview reaches Kilkeel.

Also, the Kilkeel allocations are different on the Digital UK website compared to other websites I've seen or any Arquiva documents I've seen about DSO. Still in Group B however.

Killowen Mtn.'s function isn't solely to feed Kilkeel (though that is it's primary purpose), I'd assume some viewers take a feed directly off it as it has a reasonable ERP for a relay as well, also other "link" relays in Britain have been or are planning to be converting as well.
The allocations on the Digital UK website are a "latest update", they have changed from around a year or two ago at some relay sites.

Peter Henderson

The Cush wrote: »

A freeview-HD receiver will be required to receive the freeview-HD channels, which will be MPEG-4 compatible and so should receive the Irish channels also. Killing two birds the one ... etc.

For example Black Briar has been posting today about his new freeview-HD TV (like a kid with a new toy and why not ) which is receiving both the Irish DTT tests and freeview.
http://www.boards.ie/vbulletin/showthread.php?p=68362389#post68362389
http://www.boards.ie/vbulletin/showthread.php?p=68362426#post68362426
http://www.boards.ie/vbulletin/showthread.php?p=68362788#post68362788

Indeed Cush, but how many people around here will be aware of that ?

The reason why a lot of viewers around here have their aerials pointing towrds Carnmoney Hill instead of Divis is rather like the situation in Derry. Carnmoney Hill is roughly in the same direction as Clermont Cairn. Since both are vertically polerized, you can kill two birds with the one stone so to speak.

But they're going to wonder what's happened in October 2012 !

The Cush

Peter Henderson wrote: »

Indeed Cush, but how many people around here will be aware of that ?

...

But they're going to wonder what's happened in October 2012 !

Part of the MoU is a plan for a coordinated analogue switchoff information campaign both side of the border but there are always those who tend not to take notice until it slaps them in the face.

Glenelly My Home

lawhec wrote: »

All main transmitters and relay stations in Northern Ireland (from the provisional list currently on Digital UK's website) will remain in service post-DSO in Northern Ireland. Unlike however in the south and across the Irish Sea, no new transmission sites are planned.

All transmitter and relay sites will not require an aerial switch come DSO to receive all services except Plumbridge, which is changing from Group C/D to Group B.

• Plumbridge is a small relay just outside the village of the same name, serving a part of the Glenelly Valley in the Sperrin Mountains that is shielded from the Strabane relay (there is another relay station a few miles east, funnily enough called "Glenelly Valley" near the village of Cranagh), RTÉ there, at least on VHF, can be received from Truskmore though I'm not sure how reliable UHF is. Anyway, the reason for such an awkward change is that presently two of the four frequencies used at Plumbridge lie above E62. The draft plan was to use a new frequency at E48 (along with E52 and E56) but now they plan to use E50 for the BBC-A multiplex, E46 for the UTV/C4 multiplex and E43 for the HD multiplex.

What does that mean for Glenelly Valley?
This is where I live.

Sam the Aerialman

Glenelly My Home wrote: »

What does that mean for Glenelly Valley?
This is where I live.

You're fine they've just upgraded Glenelly Valley from it's pole to a tower and moved the logs.

Sam the Aerialman

lawhec wrote: »

Killowen Mtn.'s function isn't solely to feed Kilkeel (though that is it's primary purpose), I'd assume some viewers take a feed directly off it as it has a reasonable ERP for a relay as well, also other "link" relays in Britain have been or are planning to be converting as well.
The allocations on the Digital UK website are a "latest update", they have changed from around a year or two ago at some relay sites.

Killowen's only function is to put a signal into Kilkeel they are infact putting an SHF chain in place to feed Kilkeel.

An SHF chain to Kilkeel is required because the relayed signal from Killowen Mountain would fall outside the guard interval, with respect to the 'direct' signal from Divis.


The guard interval for the post-DSO UK modes of DVB-T and DVB-T2 is 28
microseconds (1/32 of 896us for DVB-T, 1/128 of 3.684ms for T2). Speed of
light is 300,000 km/s so it travels 8.4km in 28us.

As the crow flies, Divis to Kilkeel is about 57.2 km; Divis to Killowen 58.2
km, and Killowen to Kilkeel 7.2km. The difference is 8.2km, or about 27.3
us. That's a bit close.

Kilkeel certainly doesn't have line-of-sight from Divis, but we all know RF
is a black art and people get what they shouldn't be able to (and also,
don't get what they should).

At 64QAM 2/3, 1/32 gives a usable data rate of 24.13 Mbit/s, while 1/4 gives
a data rate of 19.91 Mbit/s. That's a pretty big drop in bitrate - I haven't
seen any sign of this being proposed anywhere. Ofcom's 'Reference
Parameters' says they should be using 1/32 after DSO, though it does say
they can use something different with the written consent of Ofcom.

lucernarian

Can Kilkeel receive any signal from Divis with the extensive Mourne Mountains in the way? Also, is a SHF chain the equivanent of what would be also referred to as a "microwave link"? Where are you getting this info from?

I know that Killowen Mtn. uses very directional tx and rx aerials and that over about 5 miles the 150W peak EIRP would give a very adequate signal at Kilkeel but nothing excessive by any means.

Sam the Aerialman

To_be_confirmed wrote: »

Can Kilkeel receive any signal from Divis with the extensive Mourne Mountains in the way? Also, is a SHF chain the equivalent of what would be also referred to as a "microwave link"? Where are you getting this info from?

I know that Killowen Mtn. uses very directional tx and rx aerials and that over about 5 miles the 150W peak EIRP would give a very adequate signal at Kilkeel but nothing excessive by any means.

Kilkeel has no line of sight of Divis whatsoever. An SHF chain is exactly that, it differs were a microwave link is point to point. A chain is point to point but is single frequency doesn't require any isolation between the Tx and Rx and can pass on using a baseband amp and a few line pre-amps.

Yes Killowen uses trough type aerials which are 4 stacked bow tie style dipoles phased into a harness, the aerials are made up of a backing plate and a GRP membrane. The rx feed at Killowen is one single horizontal trough which is fed on 7/8 feeder and split 4 ways into a blue streak bbc unit. Each channel is modulated, has specially designed units to stop channel fading combined and put out onto two vertical troughs. Killowen is essentially a spotlight that rains down on Kilkeel. The two structures are isolated and opposite pol so the rx doesn't wipe out the tx are fade into the frequencies. The system was cutting edge when the beeb put her into service will be sad to see the system go but technology moves on.

Sam the Aerialman

watty wrote: »

You don't have a picture of what is INSIDE the box?

No but i do have something similar.

http://s663.photobucket.com/home/AerialServices/allalbums

lawhec

Glenelly My Home wrote: »

What does that mean for Glenelly Valley?
This is where I live.

It'll only affect you if you are currently receiving BBC1, BBC2, UTV and Channel 4 from the Plumbridge relay. If you are receiving BBC1 on a frequency displayed on your TV as either 52, E52, C52, 719.25MHz or 719MHz then that'll be Plumbridge.

However the frequency allocations are not yet final and are subject to change.

There's two relays serving the Glenelly Valley area, doesn't help that one of them is called "Glenelly Valley" as that might seem to cover all of it! The Glenelly valley relay lies about a mile south-west of Cranagh on the Corramean Road, while the Plumbridge relay is about 3/4 mile south east from the village centre just off the Landahussy Road.

egal

lawhec, why do you feel the need to have that offensive icon in your posts? Would you not consider replacing it with something less salacious? Please?

Mike 1972

Surely it would be better to PM the guy (or a Mod) if youre that concerned ?

Although IMO describing some of the more dubious aerial contractors out there as "sharks" is fair comment really

lucernarian

Sam the Aerialman wrote: »

Kilkeel has no line of sight of Divis whatsoever.

I wasn't talking so much about LOS, I was referring to signal strength itself. The signal from Divis must be more than negligible if guard intervals are an issue for Kilkeel and Killowen Mountain.

As for SHF, my question is more fundamental. I assume it's based on microwave technology, i.e. super-high frequency? So why then has Killowen Mountain been assigned DSO frequencies if it's no longer going to be used? I get the feeling it's because Digital UK haven't figured out their plan for Northern Ireland yet.

Peter Henderson

Kilkeel certainly doesn't have line-of-sight from Divis

and the reason for that is a dirty great big lump of granite called the Mournes Sam. I think Thomas's Mountain and Slieve Donard are the ones that primarily get in the way (i.e. where they sweep down to the sea !).

It' s quite interesting listening to VHF radio in that region as you drive from Kilkeel through Annalong to Newcastle. Take 96.7 for example. In the Kilkeel/Annalong areas, you get Lyric FM from Three Rock. As you drive around the coast it disappears, somewhere around the Bloody Bridge/Maggie's Leap, to be all of a sudden replaced with Belfast Citybeat. I would imagine digital TV will be something similar.

I wonder how good Newcastle is re. line of site to Divis ? The Newcastle transmitter will be Freeview Lite post DSO, but just looking around the town I have noticed some quite large aerials pointing towards Divis. Can you receive Freeview at present in Newcastle ? Can you get the digital TV tests from Three Rock in the Kilkeel/Annalong area ?

Sam the Aerialman

To_be_confirmed wrote: »

I wasn't talking so much about LOS, I was referring to signal strength itself. The signal from Divis must be more than negligible if guard intervals are an issue for Kilkeel and Killowen Mountain.

As for SHF, my question is more fundamental. I assume it's based on microwave technology, i.e. super-high frequency? So why then has Killowen Mountain been assigned DSO frequencies if it's no longer going to be used? I get the feeling it's because Digital UK haven't figured out their plan for Northern Ireland yet.

If you want to talk fundamentals first law is tv signals travel in straight lines, Tx's are in the unique position that they must have line of sight to a transmitter and be in an ideal position to cover it's target area. Minimum requirements for a usable rx feed is in and around 87db, remember that the signal must be split 4 ways and separated hence why line powered amps are used. Most tx's are in use due to ghosting, when we get DTT coverage in full any multipath problems are gone but with the legacy of aerials i do believe they will switch every relay currently in use. In Northern we're in a rather unique position were we are an island. Meaning any inland transmitters can't see the radio horizon, we have lots of coastal tx's as a result.

Guard intervals are only in use in COFDM not in analogue meaning there is no encoding, someone mentioned it's much more expensive to rx off air dtt signals. The reason is simple the "bits of information" need encoded and in order to do that OEM boards are built into the 19inch units. I know the cost of self help gear so lord knows what broadcast quality gear costs per frequency. The problems with Kilkeel and Killowen have nothing to do with the guard interval it's to do the bit rate, if there's a delay in signal on analogue you get ghosting in DTT with the digital cliff you get F all.

It's SHF Microwave technology, probably a 4 dish point to point distribution system with a PC and an encoder at one end i would imagine. Killowen was issued DSO allocations just as every Tx in the land was, they're co-channel Divis PSB's so if they're not used it hardly matters. They keep chirping that same line "The plan for Northern Ireland has not been locked down" We're the only part of the UK who hasn't even seen a version 1 frequency plan from Ofcom.

Sam the Aerialman

I wonder how good Newcastle is re. line of site to Divis ? The Newcastle transmitter will be Freeview Lite post DSO, but just looking around the town I have noticed some quite large aerials pointing towards Divis. Can you receive Freeview at present in Newcastle ? Can you get the digital TV tests from Three Rock in the Kilkeel/Annalong area ?[/QUOTE]

Yes you can get reasonable Freeview in Newcastle, some problems are the early morning/ evening when the temperature lowers and the dew sets in.
The mountains can build up a lot of moisture in the air.

Newcastle Tx has perfect Line of Sight to Divis, only requires a fairly low trough aerial to receive off air. I suspect the trough was employed because they felt logs would rust much to quickly. I often wonder if they got the skew of the tx aerials wrong when they commissioned Newcastle, has altered several times over the years for unknown reasons.

reboot

lawhec wrote: »

Of course, parts of the Co. Down and Co. Antrim coasts might be able to get services from Britain and IoM TX's the same way cross-border transmissions carry in Ireland.

As mentioned a few times on the thread IOM due to transmit HD 9 days from now.

Peter Henderson

By the way, anyone know what's happening to Northern Visions TV (Belfast's local TV station) post DSO ?

I did e-mail them a while back and was told they were in negotiations with Ofcom in order to secure a slot on Freeview.

Sam the Aerialman

Peter Henderson wrote: »

By the way, anyone know what's happening to Northern Visions TV (Belfast's local TV station) post DSO ?

I did e-mail them a while back and was told they were in negotiations with Ofcom in order to secure a slot on Freeview.

I'll be honest with you i can't see them surviving. I did an "MB21" reccy up to their site at Ballygomartin, was having the wrecking ball treatment. They were broadcasting from one of the old towers on a former MOD site downhill from Divis. Are they still on air and if so were did they go?

The cost implications for smaller community stations is going to be beyond their reach, i don't know if any of you followed how difficult it was for Channel M to get clearance to use the interleaved mux at Winter Hill. Even then they got a low power setup at the base of the mast.
Arqiva have stipulated in reference documents fees and charges for site usage, site rental and maintenance mounting to tens of thousands pounds per annum. They only want their sites used (in this case Divis) The bandwidth will be sold to the highest commercial bidder.

Mike 1972

Peter Henderson wrote: »

By the way, anyone know what's happening to Northern Visions TV (Belfast's local TV station) post DSO ?

I did e-mail them a while back and was told they were in negotiations with Ofcom in order to secure a slot on Freeview.

Ive often wondered about this myself (likewise Channel 9 in L/Derry) A lot of UK mainland RSL's have thrown in the towel already and called a day. On the other hand over in the US LPTV's were allowed to keep their (analogue ) signals on the air even after all the full power stations had to keep theirs off.

Ive always thought it was the height of stupidity putting an analogue relay of TG4 on from Divis for various reasons among them the fact that the same amount of spectrum could have been used for an additional DTT multiplex carrying TG4, NVTV, and the RTE channels (including radio)

lucernarian

Sam the Aerialman wrote: »

If you want to talk fundamentals first law is tv signals travel in straight lines, Tx's are in the unique position that they must have line of sight to a transmitter and be in an ideal position to cover it's target area. Minimum requirements for a usable rx feed is in and around 87db, remember that the signal must be split 4 ways and separated hence why line powered amps are used. Most tx's are in use due to ghosting, when we get DTT coverage in full any multipath problems are gone but with the legacy of aerials i do believe they will switch every relay currently in use. In Northern we're in a rather unique position were we are an island. Meaning any inland transmitters can't see the radio horizon, we have lots of coastal tx's as a result.

Guard intervals are only in use in COFDM not in analogue meaning there is no encoding, someone mentioned it's much more expensive to rx off air dtt signals. The reason is simple the "bits of information" need encoded and in order to do that OEM boards are built into the 19inch units. I know the cost of self help gear so lord knows what broadcast quality gear costs per frequency. The problems with Kilkeel and Killowen have nothing to do with the guard interval it's to do the bit rate, if there's a delay in signal on analogue you get ghosting in DTT with the digital cliff you get F all.

It's SHF Microwave technology, probably a 4 dish point to point distribution system with a PC and an encoder at one end i would imagine. Killowen was issued DSO allocations just as every Tx in the land was, they're co-channel Divis PSB's so if they're not used it hardly matters. They keep chirping that same line "The plan for Northern Ireland has not been locked down" We're the only part of the UK who hasn't even seen a version 1 frequency plan from Ofcom.

I didn't want to talk fundamentals per se, I just wanted to know what the SHF chain was in a basic sense (I hadn't previously heard of SHF). Thanks for that. Also, why did you mention guard intervals previously if the problems with Kilkeel and Killowen have nothing to do with guard intervals? I've done my bit of physics in college, so radio waves travelling in straight lines isn't lost on me. But nor is the quirks of propagation where I can receive decent analogue from Divis despite the Cooley Mountains being in the way. I'll put it this way, what's the main reason for a SHF chain being provided for Kilkeel rather than continuing the active deflector setup at Killowen Mountain? And if a SHF chain will be used, does that mean that Killowen Mountain will cease broadcasting on UHF by 2013 after all?

reboot

Sam the Aerialman wrote: »

I wonder how good Newcastle is re. line of site to Divis ? The Newcastle transmitter will be Freeview Lite post DSO, but just looking around the town I have noticed some quite large aerials pointing towards Divis. Can you receive Freeview at present in Newcastle ? Can you get the digital TV tests from Three Rock in the Kilkeel/Annalong area ?

Yes you can get reasonable Freeview in Newcastle, some problems are the early morning/ evening when the temperature lowers and the dew sets in.
The mountains can build up a lot of moisture in the air.

Newcastle Tx has perfect Line of Sight to Divis, only requires a fairly low trough aerial to receive off air. I suspect the trough was employed because they felt logs would rust much to quickly. I often wonder if they got the skew of the tx aerials wrong when they commissioned Newcastle, has altered several times over the years for unknown reasons.[/QUOTE]
I gave a friend a set top (amplified) aerial,he lives at the Annalong end of Newcastle,Divis Freeview is not a problem,but I suppose he may be lucky in that the Sharpe Aquas Tele appears to have a good tuner.

Digifriendly

Out of interest my parents have just moved into a nursing home in Newtownards and they wanted a new flatscreen TV for their room. I bought a 22" Sony idtv and got it tuned in. While there is a relay for Newtownards most of the town seems to have aerials for Divis. The analogue tuner not surprisingly did not pick up Five but BBC1/2/UTV/Channel 4 were fine. When the Digital tuner finished scanning Multiplex C (no Sky News) was missing as well Multiplex D (no ITV4).