Transmitter locations

Charles Babbage

Why is the LW transmitter in Co. Meath and not on top of the Wicklow mountains? Tullamore was designed to service Ireland and so a central location made sense, but 252 was aimed at Britain?

kazoo106

Because it would be worse if anything - poor groundplane due to bedrock

savelongwave

Planners consult geological maps to give a rough feel for a suitable location. Then a test transmitter is erected and measurements taken out from the mast along radials to ascertain how quickly the signal falls of. They then know the most suitable location. The signal travels in the earth close to the surface so the wetter the soil the better the conductivity. In the past Radio Caroline used the high conductivity of salt water to give extended coverage.

Sam Russell

savelongwave wrote: »

Planners consult geological maps to give a rough feel for a suitable location. Then a test transmitter is erected and measurements taken out from the mast along radials to ascertain how quickly the signal falls of. They then know the most suitable location. The signal travels in the earth close to the surface so the wetter the soil the better the conductivity. In the past Radio Caroline used the high conductivity of salt water to give extended coverage.

I think Radio Caroline used the salt water to allow them to be out of reach of the British Government and its desire to close them down.

Radio Luxembourg did not have salt water but had a good reach and a benign attitude to radio broadcasting.

Athlone was the preferred location for the transmitter for ages - and I do not think it is on top of a mountain.

.

savelongwave

Athlone was just about useable in the UK until Senders Free Berlin came on the air after WW11.

Later Tullamore on a more efficient site with a full 500kW system was a vast improvement.

It gave good sky wave reception over Europe.

Finally Spectrum Radio occupied the adjacent channel and wiped out Tullamore over much of

London.

kazoo106

Did Caroline on 558 and Laser on 576 (and vice versa) not cause similar problems in the 80's before Radio Star country (London) came on air?

savelongwave

Possibly. Certainly the Pirate ship Ross Revenge wiped out 567 Tullamore until the

Irish Authorities got support from the UK.

The Ros Revenge was driven onto the Goodwin Sands the UK towed it to harbour and had it closed on a safety of life issue.

Sometime later Spectrum 558kHz came on air and provided a multicultural service

including a slot to Irish listeners at the expense of RTE Radio One reception.

kazoo106

It will be 27 years next week since the dutch raid on the Ross - I remember being on the Liverpool-Dublin ferry the night before the raid and listening to 558 clear as day on a walkman after 567 went off for the night. Little did I know then that in less than 8 hours Caroline would be gone for ever.
Wasn't it a bit OTT for the Radio Authority to be blaming Caroline for RTE1 interference and then that same Radio Authority licenses 10kw within the M25 3 years later, flattening RTE

savelongwave

I don't know exactly know the intimate details re Caroline but the bottom line as usual is money.

The UK authorities won't allow competition to dilute revenue specially post Brexit.

I don't see RTE getting access to Multiplex 2 though it might suit them to reach N.Ireland

on the pretext of serving UK emigrants in their drive for DAB.

If RTE were interested in serving N.Ireland they would not abandon LW having already closed MW.

Were RTE to access the UK multiplex they could then say that there must be no technology

border and a that a radio that works in Newry must equally work in Dundalk as already argued,

making a case for so called "legacy FM" switch off.

Infoanon

kazoo106 wrote: »

It will be 27 years next week since the dutch raid on the Ross - I remember being on the Liverpool-Dublin ferry the night before the raid and listening to 558 clear as day on a walkman after 567 went off for the night. Little did I know then that in less than 8 hours Caroline would be gone for ever.
Wasn't it a bit OTT for the Radio Authority to be blaming Caroline for RTE1 interference and then that same Radio Authority licenses 10kw within the M25 3 years later, flattening RTE

Totally avoidable raid ?? if Caroline had switched off the SW that was causing the interference to the shipping channels the Dutch would not have raided.

The legality of the raid while highly questionable did have the desired effect.
Back to the thread - AM does not need height as already mentioned - certain locations are dictated by international agreements eg Spirits 549 location while geological surveys dictate the best location - eg Green Acres in Rathfarnham was a particularly good AM site

Antenna

THe question has to be asked, why wasn't the Atlantic 252 transmitter located on the Co. Meath coast rather than 25+ miles inland ? It would have resulted in better groundwave to Britain and pushed further away areas with nighttime fading.

You will notice distant daytime LW and MW signals getting a significant boost when parked right beside the sea (due to the good conductivity of seawater), compared with even a few miles inland. And not just signals coming across the sea, long distant signals across a land path will also be boosted right on the coast compared with a few miles inland.

kazoo106

That's correct - Boyneside's 1305 in the 80's was located at the Rosnaree Hotel - on the old Dublin road Drogheda (it also hosted Club FM for a period in the 90's) however, this was a BRILLIANT site for AM propogation - perfectly audible as far inland as Manchester and receivable on a car radio in Bradford - this was only 1kW - had 252 been here it would be much better into the UK

Stasi 2.0

LW/MW(/SW?) transmission doesn't really need great height (to the same extent that VHF/UHF does anyway). It benefits more from flat land with a high water table and/or seaside location.

Why Co Meath for 252 and not somewhere on the East coast ? (In addition to the above) two requirements had to be met when choosing a site.

Legally it had to give coverage of all Ireland as the frequency had been allocated to Ireland for domestic national use. (Tullamore was specified although the rules permit some variance) but commercially they wanted to reach as much of the UK's population as possible so taking all of the above into account Clarkstown was selected.

RE: Radio Caroline the shortwave wasn't on the air the day it was raided (it had been switched off the day prior) however there were other factors at play among them the fact that the Dutch language service was carrying advertisements for tobacco products after such advertising has been outlawed in the Netherlands. The fact that the ships Panamanian registration had lapsed (probably unknown to the crew on board) gave the authorities the green light to take action. That said was a big fan of their English service during the 1988/89 period (still enjoy listening to recordings -legal broadcasters could learn a lot) -shame about the awful choice of SW frequency.

It should also be noted that Capital Radio (London) used 557 KHz in the early/mid 1970's

Antenna

Stasi 2.0 wrote: »

Why Co Meath for 252 and not somewhere on the East coast ? (In addition to the above) two requirements had to be met when choosing a site.

Legally it had to give coverage of all Ireland as the frequency had been allocated to Ireland for domestic national use. (Tullamore was specified although the rules permit some variance) but commercially they wanted to reach as much of the UK's population as possible so taking all of the above into account Clarkstown was selected.

You meant to say (25 miles) inland Co Meath , as the county does of course have a few miles of the East coast. Better still, looking at a map, would be Clougherhead Co. Louth, as it is a headland, or the other headland a few miles north of that, if a site could have been obtained (which I realise is another issue). Another advantage of such a coastal location is less surrounding houses, phone lines etc which might have RFI issues.

Surely a coastal location was considered, but what went against it? It would still have covered the island of Ireland being omnidirectional.

Was it always planned that Ireland's LW allocation sought in the 1970s was going to be used for export radio to the UK, or was it originally planned for domestic use?

kazoo106

Clogherhead is useless - it was tried about 22 years back for an oldies station on 864AM - and the groundwave in the UK was very noticable.

Direct comparisons could be made with Clogherhead and Drogheda in the 80s. Clogherhead hosted 1521 and 1611 while Drogheda hosted 1305. 1305 was stronger in NW UK than 531, 1278 or 738

Stasi 2.0

Antenna wrote: »

Was it always planned that Ireland's LW allocation sought in the 1970s was going to be used for export radio to the UK, or was it originally planned for domestic use?

IIRC it was originally going to be used for Radio 1 from Tullamore (the potential to serve Irish expats in Britain was a consideration but it was primarily intended for domestic use) Not sure why they eventually opted for500Kw on 567 but the fact that there were high power allocations for both Finland and Algeria on 254/252 may have been a consideration.
In the early 1980's consideration was given to putting a pop music "Radio 3" (domestic) service on LW in order to compete with the pirates (odd given that Radio 2 had been established for the same purpose and was struggling in this regard -although was still modestly profitable comercially) the idea was dropped as RTE would be effectively competing against itself. Around 1986 RTL approached RTE proposing a joint venture targetting the UK and three years later Atlantic 252 was born.

Infoanon

Stasi 2.0 wrote: »

In the early 1980's consideration was given to putting a pop music "Radio 3" (domestic) service on LW in order to compete with the pirates (odd given that Radio 2 had been established for the same purpose and was struggling in this regard -although was still modestly profitable comercially) the idea was dropped as RTE would be effectively competing against itself. Around 1986 RTL approached RTE proposing a joint venture targetting the UK and three years later Atlantic 252 was born.

Nova got a lot of press coverage in the 80s with its plans to launch a 500kw LW service from the Mosney site and Nova did test on 254 for a short while in the mid 80s.(using a 10kw rig IIRC)

savelongwave

According to the licence RTE had to cover the national territory meaning they couldn't pick the best site to reach London boutiques which really was a target at the time.

Wexford would have given access to S.E England but wouldn't have provided national coverage.

The existing site meant that the Wicklow and Welsh hills attenuated the signal as a commercial service.

Any UK coverage was considered as spill-over provided you covered your territory territory.

However a full power and change to 261kHz would provide a very acceptable UK and near Europe service.

Stasi 2.0

The Czech Republic would have to agree to Ireland using 261KHz

The frequency is allocated to them -even if theyre not using it.

225LongWave

The Cambrian mountains cause 60-75% attenuation of 252kHz/1190mts
Cader Idris 852m & Plynlimon 792m on a bearing of 120-135° towards London
Then on the outskirts beside A1 it reaches Saffron Green in Barnet transmitting
LBC on 1152kHz at 23.5kW since early 1975 from four 71meter masts \ 160°


They should step down to 225kHz (1333mts) even at 50kW there is a 'distant' 12x
Polish station 600kW (GPS East 24° North 55°/ compared to 252 Tipaza Algeria
10X stronger gps E 2° N 35° on same bearing as Summerhill / London / Algeria !I

Better still would be 612kHz (490m) at 1/2-wave on 248meter mast Clarkstown.