Donnybrook Tower Saorview Allocations.

Peter Rhea

UHF channels 31 & 37, 20 watt ERP (in westerly direction, if I understand parameters correctly).

Just thought it worth a mention, didn't someone report VHF testing from there a while back?

Booms

Is that pointing East? Peaking near 90 degrees. Who's it directed towards?

coylemj

Booms wrote: »

Is that pointing East? Peaking near 90 degrees. Who's it directed towards?

The peak signal is at 80 & 90 degrees. That (true) bearing from the RTE mast takes you across the northern stretches of Elm Park GC, St. Vincent's Private Hospital and across the Dart line just south of the Merrion Gates, it's out to sea after that.

Gerry Wicklow

Can confirm that VHF signal was still on air this afternoon (Wed) showing the usual mux 2 test cards.

Peter Rhea

Booms wrote: »

Is that pointing East? Peaking near 90 degrees . . .

coylemj wrote: »

The peak signal is at 80 & 90 degrees . . .

My understanding is that the numbers in the columns T - BC are dB below max. power in each 10 degree sector from 0 degrees. So the sectors with 0s would be where the strongest signal is available.

coylemj

Peter Rhea wrote: »

My understanding is that the numbers in the columns T - BC are dB below max. power in each 10 degree sector from 0 degrees. So the sectors with 0s would be where the strongest signal is available.

That stacks up in the case of Arklow where the low numbers in that spreadsheet correspond to the compass bearings taking in the nearby urban areas which are to the NW, N, NE, E and SE of the transponder.

Taking another look at Donnybrook, the area receiving below max. signal corresponds to Dublin Bay, it's a sector bounded by bearing 40 to 120.

Booms

Thanks for the explanation, that's good to know.:)

The Cush

Peter Rhea wrote: »

UHF channels 31 & 37, 20 watt ERP (in westerly direction, if I understand parameters correctly).

Just thought it worth a mention, didn't someone report VHF testing from there a while back?

They don't really need another relay in Dublin, I wonder if these allocation are for testing purposes (dvb-t2, DD2 clearance planning?) as they are in a slice of spectrum not widely used here for DTT at the moment and that spectrum will be used in the UK to clear the upper broadcast band for DD2 in due course?

coylemj

The Cush wrote: »

They don't really need another relay in Dublin, I wonder if these allocation are for testing purposes (dvb-t2, DD2 clearance planning?) as they are in a slice of spectrum not widely used here for DTT at the moment and that spectrum will be used in the UK to clear the upper broadcast band for DD2 in due course?

Donnybrook is listed in that spreadsheet as Ch.31.

Three Rock and Holywell Hill (Donegal) currently transmit Saorview on Ch.30 so how is Donnybrook 'in a slice of spectrum not widely used here for DTT at the moment'?

The Cush

coylemj wrote: »

Three Rock and Holywell Hill (Donegal) currently transmit Saorview on Ch.30 so how is Donnybrook 'in a slice of spectrum not widely used here for DTT at the moment'?

UHF channels 31-37 are in a slice of spectrum that Ofcom in the UK refers to as the 600MHz band which was cleared of analogue TV and not planned for DTT, it was to be auctioned off for services other than DTT. This was cancelled last year because of the ITU plan to allocate UHF Chs.49-60 for Digital Dividend 2 at WRC2015. TV services in the UK will now move to the 600MHz band from the upper band later this decade to make way for DD2. (Lots of documents on this over on the Ofcom site)

Ireland has pretty much followed Ofcom on this by not initially allocating any TV broadcasting in the 31-37 slice of spectrum. Mt Gabriel, as one of the last transmitters to be switched on, was the first to have an active allocation in this group of frequencies (the few others are Mux 2).

winston_1

The Cush wrote: »

This was cancelled last year because of the ITU plan to allocate UHF Chs.49-60 for Digital Dividend 2 at WRC2015.

As far as I can tell there is no such ITU plan. It was a suggestion from some African countries, that's all.

The Cush

winston_1 wrote: »

As far as I can tell there is no such ITU plan. It was a suggestion from some African countries, that's all.

It's on the agenda for WRC2015 where the rule will most likely be approved.

Key WRC-12 highlights:

Spectrum for International Mobile Telecommunications (IMT)

In addition to the use of the 790-862 MHz in Regions 1 and 3, WRC-12 considered further spectrum allocations to the mobile service, including International Mobile Telecommunications (IMT) to facilitate the development of terrestrial mobile broadband applications in the frequency band 694 – 790 MHz. This issue has been placed on the WRC-15 Agenda together with the need to consider additional spectrum allocations for the mobile service.

http://www.broadbandtvnews.com/2012/03/05/ofcom-postpones-600-mhz-auction/

The Cush

Peter Rhea wrote: »

My understanding is that the numbers in the columns T - BC are dB below max. power in each 10 degree sector from 0 degrees. So the sectors with 0s would be where the strongest signal is available.

From Comreg

Azimuths from 0º-350º degrees

The directional antenna details in the spreadsheet are ERP restrictions in dB relative to the maximum ERP.

So for example, a site with ERP of 250Watts (24dBW), and a value of 9 at 180º means that 30Watts or 15dBW (24-9) is the maximum that can be radiated at 180º.

http://www.comreg.ie/radio_spectrum/technical_parameters.542.1071.html

coylemj

For anyone using the Long/Lat data in that spreadsheet, take note that while the numbers look like decimal degrees, they are in fact degrees, minutes and seconds bolted together so that they look like decimal numbers.

Taking the Donnybrook data, it says Long -6.1328 Lat 53.185. If you input those numbers as decimal degrees (i.e. N53.1854 W6.1328), it will point to a point in Elgin Heights near the Bray South exit on the M50.

whitebriar

coylemj wrote: »

For anyone using the Long/Lat data in that spreadsheet, take note that while the numbers look like decimal degrees, they are in fact degrees, minutes and seconds bolted together so that they look like decimal numbers.

Taking the Donnybrook data, it says Long -6.1328 Lat 53.185. If you input those numbers as decimal degrees (i.e. N53.1854 W6.1328), it will point to a point in Elgin Heights near the Bray South exit on the M50.

That's where it's beamed? I can't open the attachment on this device.

Ronnie Raygun

coylemj wrote: »

... Taking another look at Donnybrook, the area receiving below max. signal corresponds to Dublin Bay, it's a sector bounded by bearing 40 to 120.

The radiation pattern looks like that of a single vertically polarised dipole (or tiers of single VP dipoles), moreso than panels, if any aerial spotters want to take a look ...

I know it's only an allocation (see Drogheda is still there), but you'd wonder why they added it to the list at this stage, if they didn't have plans for it.

zg3409

whitebriar wrote: »

That's where it's beamed? I can't open the attachment on this device.

No, It is based at RTE Donnybrook, and as far as we can make out most of the power heads on westerly, with the east side giving out far less power.

0º 10º 20º 30º 40º 50º 60º 70º 80º 90º 100º 110º 120º 130º 140º 150º 160º 170º 180º 190º 200º 210º 220º 230º 240º 250º 260º 270º 280º 290º 300º 310º 320º 330º 340º 350º

0 1 5 5 12 12 8 9 17 17 15 14 10 3 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Basically from 0 to 130 degrees the signal is weaker (East side) with normal signal to south, west and north west.

The GPS numbers are for the location of the mast, which seem to be given in a strange format.

It is probably not on air, or only used for testing at least. 20W power is not really going to do very much

whitebriar

zg3409 wrote: »

No, It is based at RTE Donnybrook, and as far as we can make out most of the power heads on westerly, with the east side giving out far less power.

0º 10º 20º 30º 40º 50º 60º 70º 80º 90º 100º 110º 120º 130º 140º 150º 160º 170º 180º 190º 200º 210º 220º 230º 240º 250º 260º 270º 280º 290º 300º 310º 320º 330º 340º 350º

0 1 5 5 12 12 8 9 17 17 15 14 10 3 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Basically from 0 to 130 degrees the signal is weaker (East side) with normal signal to south, west and north west.

The GPS numbers are for the location of the mast, which seem to be given in a strange format.

It is probably not on air, or only used for testing at least. 20W power is not really going to do very much

Thanks for that.
It would probably be strong enough as a back up supply to 3 rock should all else go down?
I know its difficult enough to get any signal in some apartment buildings near Donnybrook,where people only have upc and no outdoor aerial.

Booms

I'm picking up Mux2 on ch37 since Sunday.

I presume it's the allocated channel for Donnybrook Tower mentioned in the first post.

Booms

Also I've just realised this also explains the weakish, occasional mux1 I've been receiving on channel 31 - still there at the moment.

StreetLight

Has there been any noteable activity from Donnybrook since the nationwide switch-on of Multiplex 2?