Truskmore (405 switchoff polorisation changes and RTE2)

Mike 1972

Does anyone know much about the changes at Truskmore in the late seventies ?

I was young at the time but I remember (barely) we used to get RTE on 405 and 625 we were using an ancient TV with indoor aerial. My Dad maintained the picture was better on 405 (maybe it was on the dodgy setup we were using) although there was the odd day when reception seemed to be better on 625 (Channel I although it also came in on Channel H which I think might have been the Croaghmoyle relay back then)

Then 405 disappeared but then there was something (this is the bit Im most curious about the hows and whys of) aerials were changed from vertical polarisation to horizontal.

Later (weeks/months/a year Im a bit fuzzy on dates) I remember looking for the newly opened RTE2 on a (rather big) tuning knob on our TV. I found it on Channel 10 (Yes It was 625 but our channel selector only had I H F D and B lettered positions -odd the things that sticks in ones mind)

We also had some friends (who had an outside aerial and lived higher up) who used to watch something called UTV (presumably on 405 from Strabane as they didnt have any BBC stuff) but it disappeared around 1981. (This could have been a fault with their set or aerial as 405 from the UK remained on until 1985 unless there was a power reduction ??) at the time they blamed it on a local pirate radio station which had just opened although their UTV never came back after the pirate closed !

Later (c 1983) BBC1 appeared very weak (and only B&W) somewhere on the VHF band (by this stage we had progressed to a 625 only colour set with preset tuning but no way of identifying what channel/frequency one was tuned to) this lasted for a few months (reception varied from totally unintelligible to watchable-if-there-was-nothing-on-RTE) until one day it disappeared suddenly mid-programme and never returned Ive never been to determine the origins of this VHF signal (possibly a spurious signal from a deflector or someones masthead amp gone haywire) There was a UHF deflector in our aera although through some freak of local topography we never could get a satisfactory signal from it (even with a proper UHF aerial/amp) although neighbours four houses up the street could (sort of)

Later I came across a World Radio TV handbook (1986) which listed Truskmore as using Channels J (RTE1) and G (RTE2) Dont remember RTE1 being on anything other than I from Truskmore So Im assuming it was a misprint although I had a portable set ("Renyolds") for a long time which had all the channel positions except I but which got RTE1 on J (Croaghmoyle at this stage was on D for RTE1 and F for RTE2) later when I was living in Dublin (and had access to cable) I was able to confirm this thing didnt actually get Channel J but its Channel I position was mislabeled as J

So to clear up some unanswered childhood questions does anyone know:
1) The reasons for the polarisation change (if it ever happened) at Truskmore and how it was implemented
2) Any better reasons for the premature disappearance of our friends UTV signal
3) Did Truskmore ever use Channel J and is so why
4) Why some old TV sets had incorrectly/misleadingly labelled channel selectors.

As a kid I was fascinated by the nuts and bolts of television although for the large part I didnt have the same interest in (most of) the actual programmes as my peers. (Come to think of it..........)

rlogue

Truskmore was originally vertically polarised for both the 625 and 405 transmissions. Since Truskmore shared channel G for RTE 2 with Mullaghanish it was decided to switch polarisation for Truskmore 625 to horizontal at the point at which RTE 2 transmissions commenced in the summer of 1978.

This also coincided with the closure of the 405 transmissions on channel 11.

Channel J had a short life - it was used for RTE 2 from Kippure and Moville briefly but was discontinued in favour of channel E for RTE 1 and Channel H for RTE 2 from these sites and Maghera. For the same reasons Maghera is vertical and Kippure is horizontal as both sites carry RTE 1 and RTE 2 on analogue VHF. Moville is now UHF only but will probably close after analogue switch off. A bizarre decision as Moville fills in a lot of the North Antrim coast.

Mike 1972

rlogue wrote: »

Truskmore was originally vertically polarised for both the 625 and 405 transmissions. Since Truskmore shared channel G for RTE 2 with Mullaghanish it was decided to switch polarisation for Truskmore 625 to horizontal at the point at which RTE 2 transmissions commenced in the summer of 1978..

How exactly was the polarisation switch implemented though ?

Did they suddenly change it one day (would have caused a lot of disruption since it would have been impossible for everyones aerial to be changed on the same day) ?

Did they have a transition period of mixed polarisation ?

Or did they have a transition period (between the 405 closure and just before RTE2 opening) of RTE1 being carried on both G (Horizontal) and I (Vertical) with both going Horizontal ultimately ?

rlogue wrote: »

Channel J had a short life - it was used for RTE 2 from Kippure and Moville briefly but was discontinued in favour of channel E for RTE 1 and Channel H for RTE 2 from these sites and Maghera.

Any idea why did they ever bother with Channel J at all ? Surely a lot of sets wouldnt even have been capable of tuning into it (since the original spec only went up to I) ?

Couldnt they have used E & H from day one. (or was E unusable prior to the 405 switchoff in the UK) and why did it take so long to implement Channel E as a solution to the Spanish interference to Maghera ?

Speaking of Maghera I remember hearing that it was originally supposed to use Channel A but on account of fears that it would affect peoples reception of 405 line BBC1 on Channel 1 from Divis Ireland managed to negotiate an amendment to the Stockholm plan enabling Maghera to use Channel B instead and that Channel A was only ever used in Ireland for cable TV.

rlogue wrote: »

Moville is now UHF only but will probably close after analogue switch off. A bizarre decision as Moville fills in a lot of the North Antrim coast.

Did anyone in NI (or Donegal) loose reception of RTE with the switch to UHF (given that VHF signals often travel slightly better over difficult terrain etc) and surely if there is no DTT from Moville there will be protests from these viewers when they are deprived of the Irish channels. The official response will probably be "let them use Saorsat" but remember the storm-in-a-teacup up here when 567 KHz got turned off (even though 252 comes in better)

rlogue

RTE have managed the ASO in their own unique way Mike. Tell the consumers little or nothing, encourage punters to remain analogue and keep everything a big secret until presumably the eleventh hour.

It wouldn't happen anywhere else.

watty

They certainly want to pull out all the stops shortly.
technical launch 31st October 2010
Full Public Launch date unknown! (Between q2 2011 and Dec 2011)
Analogue Switch off October 2012

After 13 years since first tests it looks like fastest change over in history, maybe only 15 months or less from Full Public Saorview launch to Analogue closedown!

Still no Publicity Campaign nor list of approved products. However I blame BAI (BCI) and Government for most of the Shambles.

Digifriendly

Mike 1972 wrote: »

Did anyone in NI (or Donegal) loose reception of RTE with the switch to UHF (given that VHF signals often travel slightly better over difficult terrain etc) and surely if there is no DTT from Moville there will be protests from these viewers when they are deprived of the Irish channels. The official response will probably be "let them use Saorsat" but remember the storm-in-a-teacup up here when 567 KHz got turned off (even though 252 comes in better)

I think that Holywell Hill with a decent aerial setup is available for those in the North Antrim/East Derry area who at present use Moville. It also has added advantage of TV3 which Moville doesn't. Having said that most aerials along the Co. Antrim coastal area aim for Moville rather than Holywell Hill.

Galway

Digifriendly wrote: »

I think that Holywell Hill with a decent aerial setup is available for those in the North Antrim/East Derry area who at present use Moville. It also has added advantage of TV3 which Moville doesn't. Having said that most aerials along the Co. Antrim coastal area aim for Moville rather than Holywell Hill.

Places in Inishowen, like Carndonagh and Ballyliffin depend on Moville for their RTÉ and TG 4 reception. The mountainous terrain shield these locations from Holywell Hill, Sheriff Mountain (BBC, UTV, CH4, CH5) nr Derry, and Limavady. These places rely on deflectors for BBC/UTV etc and also TV3. You can only really get Holywell Hill and UK TV from NI once your'e over the top of the hill looking down on Quigley's Point and Lough Foyle. I dont know where they are going to get DTT from if Moville is shut down at ASO. Saorsat will be RTÉ's answer, I guess. There is a very low power relay at Clonmany where there are problems receiving from Moville.

rlogue

Holywell Hill does not get over the North Antrim coast like Moville does, and I fully agree with Galway's post - Quigley's Point is a particular Holywell Hill blackspot as only houses on higher ground can get a signal off it.

Thanks to RTE's unique attitude of secretiveness on this subject we do not know if Moville will be replaced with a DTT site or will a lot of North Donegal and Antrim need Saorsat.

lawhec

rlogue wrote: »

Channel J had a short life - it was used for RTE 2 from Kippure and Moville briefly but was discontinued in favour of channel E for RTE 1 and Channel H for RTE 2 from these sites and Maghera. For the same reasons Maghera is vertical and Kippure is horizontal as both sites carry RTE 1 and RTE 2 on analogue VHF. Moville is now UHF only but will probably close after analogue switch off. A bizarre decision as Moville fills in a lot of the North Antrim coast.

Moville, as a 625 line VHF transposer, used channels H & J for RTÉ 1 and 2 respectively, as did the Letterkenny transposer - Moville used horizontal polarisation and Letterkenny vertical. These two sites along with Kippure (for a time) were the only TX sites I know myself that used Channel J in the Republic.

Channel J had the advantage in that is was a "clear" frequency using a frequency block between 222-230MHz that wasn't part of the 405 line frequency allocations used in Ireland or the UK, though since its use at Kippure was only intended to be a low power filler in Co. Wicklow for RTÉ 2, it was probably shared with "other users" outside these coverage areas. Not sure when Kippure stopped using Channel J, but at Letterkenny and Moville both sites started UHF services in the late 90's and shut down VHF around 2000 IIRC, it was shortly after this that Score NI launched its DAB service which required Channel J to be cleared.

As for Channel E, from going through old lists, its frequency allocations overlapped with channels A7 & A8 for 405 lines, and A8 was used at Strabane, Presely and the Isle of Man so it didn't look like Channel E could have been used from Kippure at least and possibly Maghera until the 405 line services were switched off from these sites.

lawhec

watty wrote: »

They certainly want to pull out all the stops shortly.
technical launch 31st October 2010
Full Public Launch date unknown! (Between q2 2011 and Dec 2011)
Analogue Switch off October 2012

After 13 years since first tests it looks like fastest change over in history, maybe only 15 months or less from Full Public Saorview launch to Analogue closedown!

Still no Publicity Campaign nor list of approved products. However I blame BAI (BCI) and Government for most of the Shambles.

Berlin's DTT switchover IIRC took less than a year.

Mike 1972

Did the UK 405 line transmitters remain on full power right until the end or was the power turned down a few years before (might explain our friends losing UTV). The Band 1 (625) transmissions from Maghera (Channel were reduced from 100Kw to 10Kw over a period of a couple of years before finally closing down.

lawhec wrote: »

Is, its frequency allocations overlapped with channels A7 & A8 for 405 lines, and A8 was used at Strabane, Presely and the Isle of Man so it didn't look like Channel E could have been used from Kippure at least and possibly Maghera until the 405 line services were switched off from these sites.

Presume you mean B7 and B8 ?

405 line was called System A but channel numbers had the prefix B
525 line is called System M but channel numbers have the prefix A (or J for the Japanese variant)
Wonderfully simple arrangement isint it.......

lawhec wrote: »

Berlin's DTT switchover IIRC took less than a year.

But then again the switch from SECAM to PAL (for Easterners) was even quicker (at least in that instance most of them already had dual standard sets though)

Galway

lawhec wrote: »

As for Channel E, from going through old lists, its frequency allocations overlapped with channels A7 & A8 for 405 lines, and A8 was used at Strabane, Presely and the Isle of Man so it didn't look like Channel E could have been used from Kippure at least and possibly Maghera until the 405 line services were switched off from these sites.

Channel E from Maghera was only operational from 1992, and channel B was not shut down finally until 1999 (I think). The UK 405 line system was shut down by 1985, so it took some time until RTÉ got round to sorting out the second rate reception viewers had to endure in the west in the summer months due to Sporadic E interference. RTÉs attitude was that it 'only happened for few days a year', reception could be severly wiped out if there was a sustained opening in the ionosphere esp in fringe areas. Cairn Hill was established to provide the Midlands with improved reception where there was a gap in reception and where many viewers in the south Roscommon area were using Maghera Channel B. Despite the 800kw output results outside the service area in places like Tuam were disappointing. Obviously the aerial configuration is such than signal quality fell off rapidly outside the intended service area. CH was used to supply RTÉ 1 and the then NET 2 to the MMDS mast at Tonabrucky when it started transmitting in 1990, with the BBC/ITV signals coming from the receiving tower at Kilconnell nr Ballinasloe, where good quality pictures from Brougher Mountain (Enniskillen) came through by some quirk at this location.. RTÉ 1 and NET 2 where removed from the system once channel E was on the air from Maghera in 1992.

watty

lawhec wrote: »

Berlin's DTT switchover IIRC took less than a year.

Not a whole Country

lawhec

watty wrote: »

Not a whole Country

A quick search lands me on the fountain of knowledge to give Luxembourg - commenced DTT on 4th April 2006, started closing analogue services the same day with full analogue shutdown achieved by 1st September 2006!

Mike 1972

To be entirely fair though Luxembourg could probably be covered in its entirity with a single TX

I remember picking up Maghera channel B near Listowel around late 1998/early 1999, it was very noisy but I was able to make out the closedown caption on the screen in the top left corner. Said something along the lines of "this service will cease shortly, retune to channel E or contact your dealer."

Channel A was never used anywhere in Ireland to the best of my knowledge. Channel C was used by the Glanmire relay.

rlogue

And Donnybrook, which closed not long after Three Rock went into service.

Mike 1972

Karsini wrote: »

or contact your dealer..

Now I know some people might find themselves at a loose end when their telly stops working but are drugs really the answer