DS Forums

 
 

RTE Long Wave 252 reprieve ?


Reply
Thread Tools Search this Thread
Old 13-11-2016, 10:21
Vectorsum
Forum Member
 
Join Date: Apr 2011
Location: Future EU Scottish Republic
Posts: 821
Just to clarify, 252LW usually carries the regular RTE Radio 1 (as on FM) service not the digital radio service (on DAB/DTT/online) called 'RTE R1 Extra', EXCEPT on Sunday mornings when religious output is on LW and RTE Radio 1-Extra and also for occasional sports outputs.
Good stuff.

There is sideband energy beyond 2kHz, otherwise it would sound extremely muffled (notwithstanding that many modern receivers sound that way on MW/LW due to the poor design of the receivers!). Any filter would have to knock out all the sidebands as well as carrier, an AM receiver (or anything acting as an AM receiver) will receive SSB (or DSBSC) transmissions for instance as an unintelligible 'duck quack' type sound despite no carrier present.
True, but Clarkstown the same as pretty much all high power LW installations since the mid 80s doesn't broadcast AM, it broadcasts PulsAM. The resulting spectrum consists of the carrier, a central region of roughly +/-1kHz corresponding to the foot and summit of the carrier slew, and complex harmonics that are a function of the carrier slew rate and duty cycle, where the 'amplitude' of the audio input corresponds to the instantaneous duty cycle. Have a look at the spectrum up close in the Peterborough SDR waterfall (use the 'Zoom In' button), it's quite mesmerising.

This morning when I took a quick look at 252 to check the SDR was up and running, there was a piece of flute music which generated a beautiful pattern of switching transients. Provided you notch out roughly +/-2 kHz then these transients can only beat with each other to produce stray audio. Even for a pure tone these are only a functional of the duty cycle, switching frequency, input audio frequency and input audio amplitude, so will just sound like anharmonic noise.
I remain unconvinced that a suggested move to 261kHz (just 7kHz higher than the original frequency used - 254kHz ) would have an impact on telephone line filters.
Fair enough, until someone rocks up on this thread who can clarify whether it's an LC shunt or more complex LP filter that's in use, no-one can say for certain, and I'm not sure anyone monitoring this thread is very much interested either. Deck chairs, Titanic, etc....
Vectorsum is offline   Reply With Quote
Please sign in or register to remove this advertisement.
Old 15-11-2016, 17:12
Ex Pat
Forum Member
 
Join Date: Feb 2011
Location: Just passin' through
Posts: 3,371
RTE on 252 broadcast in AM.
Pulse AM is something different.
Ex Pat is online now   Reply With Quote
Old 15-11-2016, 22:18
Ex Pat
Forum Member
 
Join Date: Feb 2011
Location: Just passin' through
Posts: 3,371
Good stuff.

True, but Clarkstown the same as pretty much all high power LW installations since the mid 80s doesn't broadcast AM, it broadcasts PulsAM. The resulting spectrum consists of the carrier, a central region of roughly +/-1kHz corresponding to the foot and summit of the carrier slew, and complex harmonics that are a function of the carrier slew rate and duty cycle, where the 'amplitude' of the audio input corresponds to the instantaneous duty cycle. Have a look at the spectrum up close in the Peterborough SDR waterfall (use the 'Zoom In' button), it's quite mesmerising.

This morning when I took a quick look at 252 to check the SDR was up and running, there was a piece of flute music which generated a beautiful pattern of switching transients. Provided you notch out roughly +/-2 kHz then these transients can only beat with each other to produce stray audio. Even for a pure tone these are only a functional of the duty cycle, switching frequency, input audio frequency and input audio amplitude, so will just sound like anharmonic noise.
Fair enough, until someone rocks up on this thread who can clarify whether it's an LC shunt or more complex LP filter that's in use, no-one can say for certain, and I'm not sure anyone monitoring this thread is very much interested either. Deck chairs, Titanic, etc....
You really know nothing.
Ex Pat is online now   Reply With Quote
Old 16-11-2016, 04:01
Vectorsum
Forum Member
 
Join Date: Apr 2011
Location: Future EU Scottish Republic
Posts: 821
You really know nothing.
Would you care to expand. Rather than just post your usual vague notions, inaccuracies and useless rubbish.
Vectorsum is offline   Reply With Quote
Old 16-11-2016, 09:51
hanssolo
Forum Member
 
Join Date: May 2004
Posts: 13,572
RTE on 252 broadcast in AM.
Pulse AM is something different.
Looking at the soec of the 2007 Transradio 252 transmitter it does have PDM Pulse Duration Modulation which is equivalent to PWM Pulse Width Modulation or PulseAM which makes the AM transmitter more effecient.
But with the low listening to 252 still a high cost per user and RTE is still saying it will be switched off in 2017 with existing users moved to digital (online and satellite).
The 10 year old transmitter could be sold and work on MW, India might be a buyer if it is still capable of DRM. But with decomissioning, transport and reinstall is it worth it?.
hanssolo is online now   Reply With Quote
Old 16-11-2016, 10:39
Ex Pat
Forum Member
 
Join Date: Feb 2011
Location: Just passin' through
Posts: 3,371
Would you care to expand. Rather than just post your usual vague notions, inaccuracies and useless rubbish.
My notions are not vague.
It is AM. That is it.
What you see in the waterfall of 252 is exactly the same as what you will see in the waterfall of a "conventionlly" modulated AM ttansmitter.

The only inaccuracies are in your posts.
Ex Pat is online now   Reply With Quote
Old 16-11-2016, 10:41
Ex Pat
Forum Member
 
Join Date: Feb 2011
Location: Just passin' through
Posts: 3,371
Looking at the soec of the 2007 Transradio 252 transmitter it does have PDM Pulse Duration Modulation which is equivalent to PWM Pulse Width Modulation or PulseAM which makes the AM transmitter more effecient.
But with the low listening to 252 still a high cost per user and RTE is still saying it will be switched off in 2017 with existing users moved to digital (online and satellite).
The 10 year old transmitter could be sold and work on MW, India might be a buyer if it is still capable of DRM. But with decomissioning, transport and reinstall is it worth it?.
Yes, the transmitter uses PDM to generate the modulation.
Pulse AM is different.
Ex Pat is online now   Reply With Quote
Old 16-11-2016, 10:43
Vectorsum
Forum Member
 
Join Date: Apr 2011
Location: Future EU Scottish Republic
Posts: 821
...The 10 year old transmitter could be sold and work on MW, India might be a buyer if it is still capable of DRM. But with decomissioning, transport and reinstall is it worth it?.
I thought that the DRM modulator was a retrofit and had been flogged off since? Would be interesting if it were still kicking around at Clarkstown.
Vectorsum is offline   Reply With Quote
Old 16-11-2016, 12:01
Ex Pat
Forum Member
 
Join Date: Feb 2011
Location: Just passin' through
Posts: 3,371
I thought that the DRM modulator was a retrofit and had been flogged off since? Would be interesting if it were still kicking around at Clarkstown.
It wasnt a retrofit. The tx was designed for DRM and It wasn't "flogged off", it was returned.
Ex Pat is online now   Reply With Quote
Old 16-11-2016, 14:33
Maggie_King
Forum Member
 
Join Date: May 2013
Posts: 242
Any update on the "consultative steering group" that RTE are working with ? The campagain to save 252, move to 261 etc seems to have gotten very quiet recently
Maggie_King is offline   Reply With Quote
Old 16-11-2016, 18:41
swb1964
Forum Member
 
Join Date: Jan 2015
Posts: 2,448
Is there actually any campaign to move to 261, outside of this and maybe a few other bulletin boards?
swb1964 is offline   Reply With Quote
Old 16-11-2016, 21:02
Ex Pat
Forum Member
 
Join Date: Feb 2011
Location: Just passin' through
Posts: 3,371
Is there actually any campaign to move to 261, outside of this and maybe a few other bulletin boards?
Simple answer, no.
Ex Pat is online now   Reply With Quote
Old 16-11-2016, 22:57
Maggie_King
Forum Member
 
Join Date: May 2013
Posts: 242
Is there actually any campaign to move to 261, outside of this and maybe a few other bulletin boards?
The official save lw campaign has mentioned it a few times http://savertelongwaveradio.com/the-...t-be-extended/
Maggie_King is offline   Reply With Quote
Old 21-11-2016, 15:54
35321
Forum Member
 
Join Date: May 2004
Location: southern Ireland
Posts: 126
RTE's 252LW due to have an outage for several hours from around 10AM this Wednesday:
according to http://www.rte.ie/aertel//desktopxhtml/169-2.html

Due to essential maintenance work, our Summerhill transmitter will be off the air from 10:00 to 17:00 on the 23rd of November 2016 .

This work will affect the Radio One Long Wave service from this site.

2rn apologise for any inconvenience caused by this necessary work.
35321 is offline   Reply With Quote
Old 21-11-2016, 16:24
swb1964
Forum Member
 
Join Date: Jan 2015
Posts: 2,448
Maintenance? On something due to close? Or does this confirm the reprieve?
swb1964 is offline   Reply With Quote
Old 21-11-2016, 17:28
david16
Forum Member
 
Join Date: Nov 2001
Location: Central Belt
Posts: 12,277
Simple answer, no.
It's better to listen to it on DVB, DAB, TuneIn, Irish Radio Player and FM than on the old lady of LW.

Time to shutdown both Radio 4 LW and RTE LW and so end broadcasting on the platform in both the UK and Ireland.
david16 is offline   Reply With Quote
Old 21-11-2016, 17:52
Mark C
Forum Member
 
Join Date: Dec 2001
Location: Hampshire
Posts: 8,079
RTE's 252LW due to have an outage for several hours from around 10AM this Wednesday:
according to http://www.rte.ie/aertel//desktopxhtml/169-2.html
23rd November. Now that date rings a bell
Mark C is offline   Reply With Quote
Old 21-11-2016, 21:36
882657
Forum Member
 
Join Date: Oct 2009
Posts: 476
Why does Divid16 want to kill off long wave broadcasting? What is it to him how other people listen to radio?
882657 is offline   Reply With Quote
Old 21-11-2016, 21:54
ney
Forum Member
 
Join Date: Jun 2002
Location: Scotland, Dunfermline Area
Posts: 10,699
Some newer radios in the last few years don't seem to have LW band anymore. The just have FM/AM(MW) or in some cases just FM/DAB.
I still got an old portable battery radio that I got in the late 90s that I hardly ever use anymore and that has FM/AM(MW)/LW and Two short Wave bands.

Darren
ney is offline   Reply With Quote
Old 21-11-2016, 21:58
Resonance
Forum Member
 
Join Date: Jan 2010
Posts: 9,206
Some newer radios in the last few years don't seem to have LW band anymore. The just have FM/AM(MW) or in some cases just FM/DAB.
I still got an old portable battery radio that I got in the late 90s that I hardly ever use anymore and that has FM/AM(MW)/LW and Two short Wave bands.

Darren
Yes, not many portables seem to have LW. Strangely most car DAB radios also seem to have LW (and FM/MW).
Resonance is offline   Reply With Quote
Old 22-11-2016, 16:16
Craig Kelly
Forum Member
 
Join Date: Mar 2004
Location: Glasgow
Posts: 1,545
Why does Divid16 want to kill off long wave broadcasting? What is it to him how other people listen to radio?
Probably because it costs a small fortune to keep the transmitters on, large antenna systems which require an equally large site area, etc., etc., and really not that many people listening to LW since any LW opt-outs of BBC R4 on LW are carried on DAB> as a secondary service.
Craig Kelly is offline   Reply With Quote
Old 22-11-2016, 16:32
Gerry1
Forum Member
 
Join Date: Sep 2005
Posts: 2,436
any LW opt-outs of BBC R4 on LW are carried on DAB> as a secondary service.
Not correct: the noon shipping forecast is LW only, and Yesterday in Parliament is often LW only when there aren't enough bits available, e.g. during pop-ups.
Gerry1 is offline   Reply With Quote
Old 22-11-2016, 17:35
hanssolo
Forum Member
 
Join Date: May 2004
Posts: 13,572
Like 252 closing in 2017, (the maintenance will keep the site going untill 252 listeners go to internet or satelite and the outage will give a chance to see who complains about the break), notice on 198 was given in 2011 that it will close in about 10 years or if the transmitter is too expensive to repair
http://www.radiotimes.com/news/2011-...ion-must-mourn
we're going to lose BBC Radio 4 on 198 longwave. Maybe not today, maybe not tomorrow. But sometime - and the BBC isn't quite sure when, because it depends when the equipment next breaks down.
Most likely when the electric switching contract ends iin 2021 and more boats get Navtext and satellite warning systems.
hanssolo is online now   Reply With Quote
Old 22-11-2016, 18:39
oscar1
Forum Member
 
Join Date: Nov 2005
Location: Back of beyond
Posts: 1,929
Most likely when the electric switching contract ends iin 2021 and more boats get Navtext and satellite warning systems.
The shipping forecast isn't just for large boats ---- it's also for dinghy sailors,pleasure craft ,inshore fishermen and anyone who lives on the coast (and inland) --- in other words anyone who needs an up to date forecast and isn't near the internet,mobile phone coverage or in range of a Coastguard station to get the every 3 hours forecast.
I'm lucky --- I have a hand held VHF radio and a local Coastguard mast ..
Regards
oscar1 is offline   Reply With Quote
Old 22-11-2016, 18:59
lundavra
Forum Member
 
Join Date: Dec 2009
Posts: 25,462
Not correct: the noon shipping forecast is LW only, and Yesterday in Parliament is often LW only when there aren't enough bits available, e.g. during pop-ups.
I would not have it would be impossible to put the noon shipping forecast on DAB as a secondary service. But why is the shipping forecast necessary, hardly anyone uses it. The MCA put out forecasts on VHF all day, most vessels have electronic systems to get the forecasts and gale warnings.
lundavra is offline   Reply With Quote
 
Reply




 
Forum Jump


All times are GMT. The time now is 23:46.