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Whats the most powerful FM and TV transmitter


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Old 08-02-2010, 12:51
fmradiotuner1
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HI

I tried looking this up on Google but all this crap comes up about MP3 transmitters

Also how far does the signal go on the most powerful FM and TV transmitters

Is it France Info 105.2 which I read was 500KW?
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Old 08-02-2010, 13:15
efo
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Are you after the info for transmitter power or ERP from various transmitters, because several UK UHF transmitters run an ERP of 1 megawatt ( C.P, Sandy Heath etc )
Henry
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Old 08-02-2010, 14:12
Rakim
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...several UK UHF transmitters run an ERP of 1 megawatt ( C.P, Sandy Heath etc )
Incorrect - Sandy Heath's, Crystal Palace's, etc transmitters do not 'run an ERP of 1 MegaWatt'... Transmitters do not have an ERP - They have an actual output power. It's the antenna system which has the ERP...

So, do you mean 'most powerful transmitter', or 'most powerful ERP'...??

I think we've been here before, but an example of what I mean, is that, at the FM stations, whereby the ERP is 250kW (i.e. 125kW VP + 125kW HP), the transmitters actually 'run' (operate) at around 30kW. So, the ERP from the above mentioned transmitting site's TV antenna systems might be 1MW, but that's no to say the transmitters run at that power.

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Old 08-02-2010, 14:18
fmradiotuner1
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I would say both which covers the most distance?
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Old 08-02-2010, 14:27
Rakim
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I would say both which covers the most distance?
Distance is governed by a number of factors, including antenna height & ERP, local topography, etc.
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Old 08-02-2010, 14:38
Redcoat
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Not entirely sure, but for FM, two former Irish pirate stations blasted fairly big ERP's from County Monaghan into Northern Ireland - Energy 106 used a 5kW FM transmitter fed into a 16-aerial bay (2 columns of eight) yagis directed towards Belfast which gave a gain of around 20db, giving an effective ERP of 500kW vertical polarisation. Back in the 1980's Kiss FM, also from Co. Monaghan had a similar set up which they claimed gave a 1MW (1000kW) ERP from its aerial system towards Belfast. Both stations were well known to make it over towards parts of Scotland and England even though getting a signal to actually cover Belfast was a challenge.

For television, the ERP of the most powerful analogue UHF television transmitters in the UK are at Crystal Palace, Sandy Heath and Sutton Coldfield at 1MW per channel for BBC1, BBC2, ITV and C4. Elsewhere, UHF transmitters in several parts of Australia run with up to 2MW ERP (with some DTT transmitters being allowed to run over 1MW) and in the United States, before the high-power analogue switch-off UHF transmitters there could run up to 5MW although I've read that the ERP calculation the Americans use is a little different to over here.

After DSO in the UK, the highest powered DTT multiplexes should have an ERP of 200kW.
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Old 08-02-2010, 14:50
Rakim
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IIRC, at Wrotham (WRT), when the Band II antenna system was changed to mixed polarisation, the Beeb installed 2x20kW units. Belgium had something to say about that, and on checking the Beeb found WRT had an ERP of around 360kW! To fix the problem they simply replaced one of the units with a 10kW TX (making the system 30kW, not 40kW ).

So, could Wrotham's 360kW (albeit a mistake, and no longer the case) be classed as the highest FM power in Britain...??
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Old 08-02-2010, 15:44
fmradiotuner1
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IIRC, at Wrotham (WRT), when the Band II antenna system was changed to mixed polarisation, the Beeb installed 2x20kW units. Belgium had something to say about that, and on checking the Beeb found WRT had an ERP of around 360kW! To fix the problem they simply replaced one of the units with a 10kW TX (making the system 30kW, not 40kW ).

So, could Wrotham's 360kW (albeit a mistake, and no longer the case) be classed as the highest FM power in Britain...??
I have got Radio 1 on 98.8 in Parts of Norfolk all the way down to Summerset.
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Old 08-02-2010, 15:47
Rossall
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I have got Radio 1 on 98.8 in Parts of Norfolk all the way down to Summerset.
And Radio 1 is only 120KW to keep the Frogs happy !
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Old 08-02-2010, 17:19
Powerplay
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The most powerful FM transmitters in the UK are:

Wrotham - The South East of England
Sutton Coldfield - The Midlands
Black Hill - Central & Southern Scotland
Winterhill - The North West of England
North Hessary Tor - The South West of England

Droitwich in Worcestershire is the highest powered radio TX in the UK with 500kW, this is used for BBC Radio 4 on 198kHz Long Wave!

For Medium Wave the most powerful in Europe is RTL on 1440kHz in Luxembourg.
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Old 08-02-2010, 17:21
Gareth56
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Am I right in thinking that these radio transmitters are pretty dangerous if you were to touch any "live" parts of them?
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Old 08-02-2010, 17:25
Rossall
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The most powerful FM transmitters in the UK are:

Wrotham - The South East of England
Sutton Coldfield - The Midlands
Black Hill - Central & Southern Scotland
Winterhill - The North West of England
North Hessary Tor - The South West of England
Don't you mean Holme Moss? Winter Hill is only 4KW
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Old 08-02-2010, 17:36
spanners
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In California they have the Hearst-Argyle Tower at 2000ft. Home to KCRA, KMAX, KQCA, and KSPX for a whopping total ERP of 20.1MW.
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Old 08-02-2010, 17:43
Powerplay
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Don't you mean Holme Moss? Winter Hill is only 4KW
Yes, I stand corrected
I always think high power FM from the BBC Nationals came from Winter Hill because its the main TV mast.

Where do Manchester & Liverpool get the BBC nationals on FM from?
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Old 08-02-2010, 18:26
Rossall
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Yes, I stand corrected
I always think high power FM from the BBC Nationals came from Winter Hill because its the main TV mast.

Where do Manchester & Liverpool get the BBC nationals on FM from?
Holme Moss (and Llangollen is the strongest in Liverpool City Centre).

The BBC NR from Winter Hill is very directional and mainly a filler for the Preston area.

http://www.mds975.co.uk/txmaps/BBC/N...WinterHill.JPG
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Old 08-02-2010, 18:26
Redcoat
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The most powerful FM transmitters in the UK are:

Wrotham - The South East of England
Sutton Coldfield - The Midlands
Black Hill - Central & Southern Scotland
Winterhill - The North West of England
North Hessary Tor - The South West of England
Winter Hill is only a mid-powered filler. The rest of the transmitters listed, As a rule the maximum mixed ERP used for BBC national stations is 250kW - North Hessary Tor "only" is 160kW and Wrotham is 125kW for Radio 1. As well as the other BBC national stations from Wrotham, Sutton Coldfield and Black Hill, other 250kW transmissions come from Rowridge (IoW), Sandle (Cumbria & SW Scotland), Holme Moss (North England), Talconeston (East Anglia), Wenvoe (South Wales & Bristol), Blaenplwyf (Mid-Wales coast) and Divis (Northern Ireland).

Droitwich in Worcestershire is the highest powered radio TX in the UK with 500kW, this is used for BBC Radio 4 on 198kHz Long Wave!
The TalkSport transmission from Droitwich on 1053kHz is reported to have an ERP of 500kW as well. Some sources for BBC Radio 4 from the site suggest that it is running at 400kW.

For Medium Wave the most powerful in Europe is RTL on 1440kHz in Luxembourg.
It's a powerful beast running at times with 1200kW, but according to the EMWG the following MW transmitters have the same or a higher ERP...

540kHz - Hungary, MR1 (2MW)
639kHz - Czech Rep, CR2/6 (1.5MW)
1089kHz - Russia, Station mix (1.2MW)
1179kHz - Sweden, Radio Sweden (2MW ERP at 600kW TX power)
1314kHz - Norway, Occasional broadcasters (1.2MW)

Some countries also used to have medium wave transmitters with ERPs of >1MW, but they've been shut down. Also throw long wave into the mix and again big powers up to 2.5MW are used in Europe.
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Old 08-02-2010, 18:41
Rakim
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I have got Radio 1 on 98.8 in Parts of Norfolk all the way down to Summerset.
Not really surprising as the transmitting stations at Tacolneston & Oxford are RBS off Wrotham...

BTW, Radio 1 from WRT is 62.5kW VP + 62.5kW HP (125kW MP), which is only 3dB down compared to Wrotham's other national transmissions (125kW = 21dBW. 250kW = 24dBW) The difference in service area is very little.
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Old 08-02-2010, 18:46
Rakim
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Droitwich in Worcestershire is the highest powered radio TX in the UK with 500kW, this is used for BBC Radio 4 on 198kHz Long Wave!

For Medium Wave the most powerful in Europe is RTL on 1440kHz in Luxembourg.
If we're taking AM in to account as well, did someone forget the MW transmissions from Orfordness, Suffolk, plus the VT Communications sites which transmit on SW...

BTW, the BBC tend to state (or at least used to state) transmitter output power for AM transmissions, where as commercial radio/Ofcom tend to state EMRP. A good example of this is 1458kHz from Brookmans Park... BBC GLR used to be quoted as being around 50kW (i.e. TX o/p), where as Sunrise is quoted as being around 125kW (i.e. ERMP)....

BTW, I may be wrong, but I think there's a 2MW LW mast in Poland (it may be Russia). I might be wrong... The grey matter isn't what it used to be.
(It's been fried by too many antenna systems... lol! )
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Old 08-02-2010, 18:55
HiZ
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Am I right in thinking that these radio transmitters are pretty dangerous if you were to touch any "live" parts of them?
Yes your right!
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Old 08-02-2010, 19:18
Redcoat
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BTW, I may be wrong, but I think there's a 2MW LW mast in Poland (it may be Russia). I might be wrong... The grey matter isn't what it used to be.
(It's been fried by too many antenna systems... lol! )
The Taldom long wave transmitter on 261kHz (situated about 70 miles north of Moscow) has an ERP of 2.5MW and is the most powerful AM transmitter in the world. I can get it on a very good night if I can null away RTÉ Radio 1 on 252kHz.

During the Cold War, Radio Moscow once did some very high powered tests on short wave aiming transmissions towards the USA Eastern Seaboard back in the 1980's, the directional ERP was around 5MW which they slowly built up to. When they got to 5MW they noticed that reception in Washington DC was worse than what it was at around 2MW. Even better (or worse!) was that weather patters were being affected by the transmissions! What was happening was that the transmissions were so powerful, it was in effect burning a hole in the ionosphere with most of the signal not being reflected but instead going straight out to space. The Soviets decided from their tests that the highest ERP that is useful for short wave broadcasts was around 1250kW, anything stronger either made no difference or resulted in worse reception at the target area.

The principle behind the unintended side effect of these tests is being used by the USA for HAARP.

Also, I too understand that for MW & LW transmissions the BBC publish transmitter powers (not taking aerial gain into account, while commercial stations publish the ERP. TalkSport is recorded as having an ERP of 500kW from Droitwich - a BBC list I have from the early 1990's states that BBC Radio 1 was 150kW from the same site.
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Old 08-02-2010, 20:05
Nick_G
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The most powerful FM transmitters in the UK are:

Wrotham - The South East of England
Sutton Coldfield - The Midlands
Black Hill - Central & Southern Scotland
Winterhill - The North West of England
North Hessary Tor - The South West of England

Droitwich in Worcestershire is the highest powered radio TX in the UK with 500kW, this is used for BBC Radio 4 on 198kHz Long Wave!

For Medium Wave the most powerful in Europe is RTL on 1440kHz in Luxembourg.
Don't forget Wenvoe and Tacolneston as well. These also put out 250 kW ERP and again cover huge areas.
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Old 09-02-2010, 09:23
Rabbit Rabbit
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125kW = 21dBW. 250kW = 24dBW
Whilst you are usually pretty good, would you like to have another go at this one?
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Old 09-02-2010, 10:10
Rabbit Rabbit
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The Taldom long wave transmitter on 261kHz (situated about 70 miles north of Moscow) has an ERP of 2.5MW and is the most powerful AM transmitter in the world. I can get it on a very good night if I can null away RTÉ Radio 1 on 252kHz.
Whilst it may well officially have that figure, I doubt very much that it is still operating at full power; many of the ex-Soviet mega medium wave power transmitters are a shadow of what they used to be for a variety of reasons, mainly technical failure though reducing the power to reduce power consumption is very common. A lot of the transmitters have Russian made valves which have a relatively low life so are under-run to keep them going. These days some have been modified to use Eimac or Thales vales and get 10 times the valve life - but cost real money as when a Russian valve failed they took it apart and replaced what was broken.

There's a system in Tajikistan that uses a high power transmitter and something like 26 masts to form a highly directional aerial - the problem is that the aerial was designed in Soviet days and when the Russians left they also took the paperwork so no-one knows exactly how it works, nor how to adjust it as it is off tune somewhere.

And for high power long wave, there was the Middle Eastern state who built a high power long wave so the Royal family could listen to their radio station wherever they were in the Gulf.


.

During the Cold War, Radio Moscow once did some very high powered tests on short wave aiming transmissions towards the USA Eastern Seaboard back in the 1980's, the directional ERP was around 5MW which they slowly built up to. When they got to 5MW they noticed that reception in Washington DC was worse than what it was at around 2MW. ......... The Soviets decided from their tests that the highest ERP that is useful for short wave broadcasts was around 1250kW, anything stronger either made no difference or resulted in worse reception at the target area.
I wasn't sure that this was right - many international broadcasters use 250kW short wave transmitters and a decent HRRS 4/4 array (4 dipoles high, 4 dipoles high with a reflector) can give a gain of between 15dB and 18dB so the erp is in the region of 10MW; 500kW transmitters are reasonably common as well, which doubles the erp. In the 1980s, broadcasters were replacing their services with 500kW transmitters but came to realise that they didn't really need that as if everyone was upping their power, there was no real gain so powers dropped to the 250/300kW level. And it cost a lot.

.
The principle behind the unintended side effect of these tests is being used by the USA for HAARP.
Reading the article, I see that the aerial has a gain of 31dB with "a total of 3.6 MW of transmitter power" so this is 3600 MW erp (roughly with 30dB gain) so a few hundred times that of the broadcast short wave transmitters. A similiar system was built at Orfordness - the Cobra Mist system for over the horizon radar
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Old 10-02-2010, 01:05
Rakim
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125kW = 21dBW. 250kW = 24dBW
Whilst you are usually pretty good, would you like to have another go at this one?
Oops... those dBW figures I gave were for 125W and 250W respectively.
(who forgot they were talking about kiloWatts, not Watts... See, I was right, my brain has been fried by too many antenna systems... )

Of course, the correct dBW figures are...[LIST][*]125kW = 51dBW[*]250kW = 54dBW[/LIST](30dB makes all the difference)
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Old 10-02-2010, 11:27
smorris
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BTW, Radio 1 from WRT is 62.5kW VP + 62.5kW HP (125kW MP)
Quick question...

Am I right in thinking that the better measure of the likely service area of a transmitter is the higher of the two vertical/horizontal components, rather than the sum of the two?

I believe in the USA they measure it that way, which means that they would describe our mixed polarisation transmitters as being considerably less powerful than we do... (i.e. they'd describe Radio 1 from Wrotham as 62.5kW, not 125kW)
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