DAB in Ireland: RTE multiplex closed

DMC

Its a three month trial. If deemed a success, then RTÉ will announce plans.
But do not buy a DAB radio solely for the RTÉ tests if you dont already have one. Only if you can pick up UK DAB and its proven that reception is possible, then getting one is it worth it. Reception reports are earlier in this thread.

DMC

Full power from Three Rock once more.

DMC

And its just gone off air.

Sponge Bob

DMC wrote:

Its a three month trial. If deemed a success, then RTÉ will announce plans.

RTÉ's sudden interest in matters digital stems from their VERY well founded fear that Comreg are about to eat their digital lunch for them, that well founded fear is explained clearly in this document here (see the 10 questions at the end and then work up)

We will hear a flurry of digital with everything announcements from RTÉ over the next 2 or 3 months. Plans for DTT DAB DRM ...... the lot .

byrnefm

No Three Rock signal so far today

I took my DAB radio into work this morning - no signal at all on Anglesea Road and only a very poor signal when at a window on the second floor, facing Claremont Carn (Signal Error 55 at the best). I noticed that even in my own house in Stillorgan, I can only get reception upstairs - so I'm lucky to still be able to pick it up at all during 'off-peak' hours! I'll test it tomorrow on the way to Dundrum along Lr Kilmacud Road to see what CC is like from there.

I decided to run some other tests on the signal, to see for myself just how much bandwidth the DAB signal consumes in practice. It didn't help that I only had a poor signal this morning as it made it hard to set up my radio scanner for the purpose! However, I found a spot where I could take photos of the signal strength.

All screen shots were taken from a Yaesu VR-500 receiver.

To explain the screenshots:
The frequency in each box is that at the center point.
WFM = Wide FM, as used by TV sound and FM radio.
w1.5M = 1.5MHz of bandwidth displayed across the screen
25k = each vertical pixel line is 25kHz
Maximum signal pixel height = 6 pixels (bottom line is just the base line)

As you can see, it goes from 226.6MHz to 228.125MHz. The signal does go further than that in each direction for another 0.75MHz or so but much weaker - it could be down to interference from the DAB signal.

For comparative purposes, I also took the signal of Today FM with the antenna shortened as far as possible (middle bottom) - the picture in the lower left shows the amount of signal interference on the FM band if you don't. (Note: this is probably due to the congested FM band in Dublin - in Donegal, where there are fewer channels, there is no such interference). As each vertical line is 25kHz, that puts Today FM's signal width at about 125kHz. The DAB multiplex, based solely on the screen shots, is about 1.525MHz or roughly 250kHz per 192kbit channel.

(You'll notice another small line to the right of the Today FM signal - I think that's another transmission of Today FM at 100.9MHz, though I didn't check).

While I was at it, I tuned into 12B (225.64MHz) and 12D (229.07MHz). Nada.

If you do tune into 12C with a regular receiver, all you'll hear is a sort of interference noise, though not very loudly above the regular static. (In comparison, a digital mobile phone signal sounds like a mini-machine gun going off in rapid succession, then pause, then again).

watty

Youl'd need a spectrum analyser. The VR-500 will not display BW of digital signals properly. It will underestimate.

I have access to several that would do the job, but there are a number of mountains in the way betweeen Three Rock and Limerick!

DMC

Damo's big DAB weekend update

Last night, travelling up the N3, with Clermont Carn on. (Note: Roberts RD-5 sitting on passengers seat)

Decent enough coverage most of the journey, started to kick in around Clonee while still on the bypass, good strong signal up the main street of Dunshaughlin, fine until the dip after Tara, and I didnt hear anymore until I was at Tara Mines, the north end of Navan. More or less fine then to Kells.

At home around Moynalty, I discovered indoor is a no-no, but outdoor, its 40%, quite usable. Looks like an outdoor aerial. The same for Mullagh etc, where Clermont Carn TV reception isnt that hot anyway. I'd recommend a outdoor aerial here, if its on max power. Some other unexpected news was that just a quarter of a mile as the crow flies from home, I received the weakest of signals of the BBC DAB mux, enough to tune in the band.

It was such a shame that Three Rock was off most of the day..... just arrived back in Dublin, and it was on when I came in, then off for 15 mins and just now, back on, at less power.

SPDUB

Is it possible that these tests from Three Rock could be having an impact on BBC2 analogue reception on NTL in the form of interference that looks like there is a strong signal to the side

We've had interference, here in Crumlin , that has only started in the last few days and has been confined to the daytime except for today when it has continued all evening but wasn't there up until at least 2.30 pm saturday .it has also varied in strength from time to time.

lawhec

SPDUB wrote:

Is it possible that these tests from Three Rock could be having an impact on BBC2 analogue reception on NTL in the form of interference that looks like there is a strong signal to the side

We've had interference, here in Crumlin , that has only started in the last few days and has been confined to the daytime except for today when it has continued all evening but wasn't there up until at least 2.30 pm saturday .it has also varied in strength from time to time.

I had a feeling this could have happened... :eek:

watty

SPDUB wrote:

Is it possible that these tests from Three Rock could be having an impact on BBC2 analogue reception on NTL in the form of interference that looks like there is a strong signal to the side.

Unless the Cable system is rubbish, it shouldn't be a problem ...

I never saw Analog Cable that didn't have noise and/or terrible herring bone cross channel interference on most of the channels. I had analog cable removed from one place in Dublin and three places in Limerick I lived.

The analog MMDS didn't have the herring bone and other intermod but far far too noisey. I got rid of that too when I moved out of city.


The licence for Cable/MMDS should specify quality of service limits.

DMC

BBC 2 on Dublin analogue cable.... 224 Mhz .... 12C is 227.36 Mhz .... hmmmmm

Looks like its on air all night, still on this morning.

rlogue

Of course the coaxial cable running from the cable outlet to the TV will act nicely as an antenna as well.

When I lived in Dublin Screensport (remember that??) was distributed on channel H, which at the time was also the home of RTE 1 from Kippure. Lots of lovely herringbone interference ensued, rendering Screensport unwatchable.

Of course the Dublin analogue cable system is now 35 years old, surely it's high time NTL switched it off and moved all their customers to Digital?

eoinm1

Hi Lads

Just wanted to say that this thread and the discussion on digital radio technology have proved to be both entertaining and quite informative. Thanks to everyone who have provided reception reports and other information.

It’s quite unfortunate that the discussion on the digital radio technology thread has degenerated into a slagging match, but I do believe for a healthy discussion we need to hear all the arguments for and against a technology. I for one hope that ‘digitalradiotec’ will come back and contribute to our discussions in the future.

I think everyone could have acted better and not attempted not to get on each others wick, but what’s done is done.

As for the current tests it can only be good news that RTE is doing any work on providing digital transmission systems. I like many other don’t have a DAB radio but I would get one for testing and experimenting with, but I don’t think I would be able to get any reception of the BBC DAB broadcasts so in my case it’s not work splashing out 50 to 100 pounds sterling for a radio which will be of little use for most of the time.

I hope RTE and Comreg agree on Digital standard for use in Ireland that will allow for both a good technical and commercial Digital broadcasting system.

To all the people with DAB radios enjoy the radio

Eóin

DMC

Finally.... 2 and a half years later.... I've got my Psion Wavefinder getting a signal....

\o/ indeed.

Firsty, what it looks like.... and a bit of a (very old) review
http://www.transdiffusion.org/rmc/features/digital/wavefinder.asp

Using DABbar software...

rlogue

rlogue wrote:

When I lived in Dublin Screensport (remember that??) was distributed on channel H, which at the time was also the home of RTE 1 from Kippure. Lots of lovely herringbone interference ensued, rendering Screensport unwatchable.

I remember this when I lived in Ballyfermot, although in later years when it was TCC on channel H. Sky News is also close to channel E which made RTÉ 2 from Kippure interfere with it.

I remember the herringbone interference but it was eliminated in Ballyfermot around 1994/95 when they replaced the cabling running outside all the houses.

Hissing Sideban

eoinm1 wrote:

Hi Lads

It’s quite unfortunate that the discussion on the digital radio technology thread has degenerated into a slagging match, but I do believe for a healthy discussion we need to hear all the arguments for and against a technology. I for one hope that ‘digitalradiotec’ will come back and contribute to our discussions in the future.

I think everyone could have acted better and not attempted not to get on each others wick, but what’s done is done.

Eóin

Hi All - I thought the same - no need for anyone to take a technical discussion so personally!

Heres' my input, for what it's worth:

I agree that Eureka DAB is not fab quality, in fact it sounds a bit dodgy at times, especially at 128k and below(stereo), but as far as most consumers are concerned, it is adequate for car and portable use (which is by far the way most radio listening is done)
Newer technology may offer better quality in the future, but I think that in the absence of any other standard with plenty of radios for the consumer out there, RTE are right to go for it.

Digital compression quality, even MPEG2 - can benefit from judicicious audio processing - one shouldn't use clipping, which wastes algorithm overhead trying to code the harmonics and IM distortion generated, this means no FM tuner or processor audio feeds - and limit the audio bandwidth to the lowest possible which still provides acceptable quality. For example, 30Hz - 15kHz bandwidth will actually sound better on a MPEG 2 128 k stream than 30 Hz-20kHz (this doesnt apply to systems that use Spectral Band Replication , like AAC plus though)

The downside for the independent sector is that there is not much space on Band III - the local multiplexes are all 'L' band, and almost all the radios easily and cheaply available are band III only (see below)

Andy in Waterford

INR Republic of Ireland 12A (223.936 MHz)
RTE Republic of Ireland 12C (227.360 MHz)

Local / Regional Ireland
Cavan County (IRL80024) LA (1452.960 MHz)
Dublin City (IRL80010) LA (1452.960 MHz)
Kerry County (IRL80003) LA (1452.960 MHz)
North Inishowen (IRL80026) LA (1452.960 MHz)
Waterford County (IRL80005) LA (1452.960 MHz)
Waterford City (IRL80027) LB (1454.672 MHz)
Galway City (IRL80031) LC (1456.384 MHz)
Laois/Offaly (IRL80020) LC (1456.384 MHz)
Cork City (IRL80001) LD (1458.096 MHz)
Kildare County (IRL80008) LD (1458.096 MHz)
Limerick City (IRL80030) LD (1458.096 MHz)
Sligo/S Donegal (IRL80013) LD (1458.096 MHz)
Wexford Town (IRL80028) LD (1458.096 MHz)
Clare County (IRL80019) LE (1459.808 MHz)
East Coast Wicklow (IRL80029) LE (1459.808 MHz)
Roscommon/S Leitrim (IRL80025) LF (1461.520 MHz)
Dublin County (IRL80009) LG (1463.232 MHz)
Mayo County (IRL80014) LG (1463.232 MHz)
Meath County (IRL80023) LH (1464.944 MHz)
Wexford County (IRL80006) LH (1464.944 MHz)
Tipperary County (IRL80017) LI (1466.656 MHz)
Longford/Westmeath (IRL80015) LJ (1468.368 MHz)
Galway County (IRL80018) LK (1470.080 MHz)
Monaghan County (IRL80012) LK (1470.080 MHz)
Kilkenny County (IRL80016) LM (1473.504 MHz)
Cork County (IRL80002) LN (1475.216 MHz)
Wicklow Rural (IRL80007) LN (1475.216 MHz)
Carlow County (IRL80022) LO (1476.928 MHz)
Donegal Northwest (IRL80021) LO (1476.928 MHz)
Louth County (IRL80011) LO (1476.928 MHz)
Limerick County (IRL80004) LP (1478.640 MHz)

SPDUB

rlogue wrote:

Of course the coaxial cable running from the cable outlet to the TV will act nicely as an antenna as well.

Of course the Dublin analogue cable system is now 35 years old, surely it's high time NTL switched it off and moved all their customers to Digital?

Unfortunately we have a nice long run over our roof into the back of the house for the cable and a nice direct view of Three Rock at that height and direction

As for moving us to Digital they still have not upgraded this area so that's not an option

DMC the interference did stay on all night and has been continuous in fact since yesterday evening and is strong ( a fine herring bone pattern ) at this point in time (10pm)

stylers

Howye lads,

I'm getting the 12C multiplex just grand with the scanner and external discone, and just about if i move around a bit with the rubber ducky. I'm near mullingar, but am on a height which gives me a view of the dublin/wicklow mountains.
unfortunately have no DAB receiver yet so i cant give ye a proper reception report but i just might go for one now..

Owen.

Propellerhead

I'm pretty pleased with the results so far. Up to this evening when I last checked "Fraggle" Rock was coming in loud and clear in Celbridge.

Can we keep WRN please? It's great. Nowhere else for your car radio will you get NPR (US) content which is wonderfully radical and a host of other European English language content which I would have to spend hours googling or randomly tuning my short wave radio to find.

DMC

Such a shame that I returned to Dublin on Saturday evening and was unable to try for Three Rock back home.. there's always next weekend, but good to get the Wavefinder on.

Welcome to the thread, Hissing Sideban... from what I hear L band is off the agenda, so for local radio on DAB, we'll need more frequencies, which should be internationally agreed in a year or so's time. WRN is great, its the first time I properly listened to it

One other thing... does anyone find that Radio 1 is a bit bubbly/gurgly, even though signal strength is 100% from Three Rock? Other channels seem fine and bit-rates are still 192??

byrnefm

I didn't notice it from the bit of listening to Radio 1 that I did - Today FM's was fine, at any rate. I did notice that the sound quality from at least one of the ads was awful - like an .mp3 that was set to 64kbits or lower. For the most part, however, I wouldn't have been able to tell the difference between the DAB version of Today FM and the analog version.

I noticed that the signal strength of Three Rock was turned down about 2/3 for about 20 mins at 2:35pm (I think) and then went up to 2/3 signal strength. When I tried later again at 8:30pm, it back back to full. I know that it was Three Rock as it's impossible to listen to the portable sitting down in my room with a Claremont Carn signal.

watty

The bubbling could be over processed audio feed?

If there is any typical processing on the audio (IMO an evil thing even on FM, which can cope), then the MP2 encoding is impared.

IMO at about 192k there isn't any difference between joint stereo MP2 and MP3. It is really only at lower rates that I don't use that MP3 performs better.

We use 256k MP3 for our home networked music library, but direct CD to Atrac2 for the minidisc player as going via MP3 even at 256k is noticably poorer.

I think standards even for audio on VHF FM have fallen a lot since I was a comms centre engineer in 1976, so it is too late to worry much about DAB.

160k MP2 will sound OK with some material, but not if it is processed at all. Only a little advange to MP3 or Atrac2 (supposed at 160k to be equal to 192k, but I think it depends on content).

IMO 128k MP2 joint stereo sounds worse than 128 MP3 joint stereo, but I wouldn't encode that low ever again on MP3 either. Either codec with very high separation stereo (un-natural) or dual channel audio is effectively 64K and terrible.

I can't compare other codecs as I havn't used them to encode myself or in some cases don't have them.

I've used Tmpenc for MP2 and Media Player 10 and "Lame" for MP3. Also I can compare FM radio with Satellite MP2.

Today's over processed average FM radio station compares very poorly with 192K MP3, 160K Atrac2, CD Audio or home encoded MP2 played on a DVD player.

(I use MP2 encoding for SVCD and DVD, mostly my own material, some source from 8mm analog Camcorder, some CD Audio and some home recordings in Wav format at CD Red book compatible settings using Phonic Mixer desk and Creative Sound card).

DMC

Three Rock off-air this evening.

watty wrote:

The bubbling could be over processed audio feed?

Possibly. I think the feed they are using is the one they use for satellite? I must check the delay when its back on-air...

watty

RTE Satellite doesn't sound great either.

lawhec

According to a post on D*****l S*y the DAB audio feeds to Clermont Carn are taken from the same feed as FM.

waiguoren

I couldn't receive the 6 DAB channels this morning at around 8.15am in Dublin 2. Was the Three Rock transmission turned off? I have been able to listen to it yesterday and most mornings last week. I'm based in Dublin 2 using a Sony DAB XDRS1.

I hope the DAB trial is transformed into a proper service as I enjoy listening to WRN and Lyric and Today FM via DAB and am disappointed I can't in the evenings.

I have listened to DAB in the UK for quite a few years and particulary like to listen to BBC World Service, Oneword and some of the music stations such as Real Radio and Captial Disney: none of which are available in analog. I understand the discussions about the quality of DAB but I don't think bit rates/MP2/MP3/AAC show the full picture. In the UK I was able to compare the sound from my DAB Sony Tuner (ST-D777ES) with the sound of the same station on Freeview from the Panasonic Freeview box. In both cases, linked to the same high-end amp and speakers. The sound was far superior from the Sony even though, I believe the station from the Freeview was at a higher bit rate. Of course the Sony Tuner was quite a bit more expensive and is a dedicated to sound rather than sound and pictures but this shows that what happens to the digital signal is important as well. The sound was also better on the DAB tuner than from a Sanyo Worldspace tuner.

I haven't compared the DAB signal with FM in the home but on a handheld DAB receiver in Manchester the DAB signal almost always sounds better because there is less interference. It used to be the case that you couldn't listen to DAB on the train except near the larger cities but it improving all the time.

Although I'm a big fan of DAB, maybe Ireland is better waiting before going ahead if many countries are doing the same? How does the American In Band system compare in quality terms?

Has anyone heard anymore about when the combined DAB/DRM radios will become available? I think I read that they should be around at the end of last year, but haven't been able to find anywhere online selling them. I particularly liked the look of the Starwaves one as shown 2/3rds of the way down this page:
http://www.ahrt.hu/en/services/DE4670D957E6474FBA779D3FF881742E.php

DMC

Hi waiguoren, welcome along.
It seems Three Rock was quiet all day. I have to say I'm enjoying WRN too.... radio is one thing I dont use a lot of on satellite.

Hissing Sideban

waiguoren wrote:

Has anyone heard anymore about when the combined DAB/DRM radios will become available? I think I read that they should be around at the end of last year, but haven't been able to find anywhere online selling them. I particularly liked the look of the Starwaves one as shown 2/3rds of the way down this page:
http://www.ahrt.hu/en/services/DE4670D957E6474FBA779D3FF881742E.php

I saw several working models at IBC in Amsterdam last year, but obviously there must be production difficulties - if they could have got them out by Christmas as promised, they would have for sales reasons alone. Now , I wouldn't be surprised if it at least the summer before they are available to buy. I want one though, at present I have a Ten Tec with 12kHz I.F. out which I can feed to my PC and demodulate using either Dream (works best with weaker / noisier sigs, but no SBR) or the Merlin Software AAC SBR, so best quality)

SimonMaher

Because Im such a nerd, my Accoustic Solutions portal 2 radio arrived today. Lovely receiver too, good performance on FM and DAB. Good sound too. 3 rock coming through very well with the smallest bit of antenna selected. Will take it on the road at the weekend and see what happens!

Pete

byrnefm

Three Rock is on this morning, so I tested it along Anglesea Road, as far as Ballsbridge Motors on Shelbourne Road. No break-up at all, though I was surprised that the signal error went as high as 14 at one point and was regularly between 4 and 10, considering how close to Three Rock we are here (even with buildings factored in).

Interesting program on WRN about Flexcrete - ash mixed with cement or something like that, that many of the new Navajo buildings by the four corner states in the US are being built with. I'll miss this station when it goes!