[moonraker1964]

I was checking the BBC website recently and saw that Radio 4 has various MF frequencies assigned to it.

silly question, why are these needed?

surely the 198khz signal must audible all over the UK?

bearing in mind even during daylight the other signals on long wave are clearly audible (Saarlious etc.)

Can anyone shed some light??

Dave

[hanssolo]

MW is used in Scotland and NI because of the overlap of the 3 198khz transmitters used are causing phasing problems.
Also MW is used in London, Cornwall and NI as the 198khz signal is at the edge of good reception. Other LW stations use higher power.

[redcar1]

In the Tyneside area there is overlap between the LW transmitters at Droitwich (which serves most of England but not the very far north or very far south-west) and Westerglen (which serves southern Scotland). Therefore a relay is provided on 603kHz. While the LW signal is OK here in Redcar, being on the coast the signal from Tyneside on 603kHz is very strong and actually a lot clearer than the LW although not actually intended for us.

The fact that a very significant amount of signal from Westerglen reaches here is more than adequately demonstrated when Droitwich is off air and I don't lose Radio 4 LW but just get it from a different direction.

[DVB Cornwall]

198kHz is as stated above extremely unreliable in Cornwall, overnight it usually gets swamped and during summer days it can be affected by weather conditions as well.

[Bluenile]

Here's the list of freqs off the BBC site:

Carlisle 1485 1kW

Enniskillen 774 1kW

Lisnagarvey 720 10kW

Crystal Palace 720 0.75kW

Londonderry 720 0.25kW

Newcastle 603 2kW

Plymouth 774 1kW

Redmoss 1449 2kW

Redruth MF 756 2kW

I get good daytime reception on 720 from N. Ireland here, and 603 is also listenable on a decent radio in the daytime.

[Gerry1]

Originally Posted by moonraker1964

Surely the 198kHz signal must be audible all over the UK?

Bearing in mind even during daylight the other signals on long wave are clearly audible (Saarlouis etc.)

• IF you're in free space, not a steel framed building or behind the gasholder...

• IF you're nowhere near a TV, computer, fluorescent lights...

• IF your £450 Vauxhall car radio hasn't forgotten LW...

LW is highly susceptible to the problems above, so that's why there are local fill-ins in densely populated places towards the edges of the main service area.

[graham_moreton]

Originally Posted by moonraker1964

I was checking the BBC website recently and saw that Radio 4 has various MF frequencies assigned to it.

silly question, why are these needed?

surely the 198khz signal must audible all over the UK?

An example where it isn't ok - especially for the anaraks !!

Drive the pretty route into Scotland along the A38 from Corbridge northwards to the Scottish border at Carter Bar, with your car radio tuned to Radio-4 Long Wave 198 kHz.,

Reception at Corbridge and Carter Bar should be ok. But in the middle !!!

You will drive through what is technially known as a "Mush Area" between the Droitwich and Westerglen 198 kHz transmitters.

Stop at at the Carter Bar roadside cafe. I can almost guarantee that you will need a cuppa.

Graham Moreton

[Craig Kelly]

Originally Posted by hanssolo

MW is used in Scotland and NI because of the overlap of the 3 198khz transmitters used are causing phasing problems.

Radio 4 on 720 kHz MW from Lisnagarvey, Northern Ireland does overspill into southern Scotland in areas like Dumfries and Galloway, Ayrshire and most of Argyll and does provide a reliable service where 198 kHz LW is poor.

In Scotland, the 198 kHz LW service is 50 kW from Westerglen serving mostly central Scotland and for the north of Scotland, also on 198 kHz with 50 kW from Burghead on the Moray coast. The LW antennas at these sites are rather complicated in an effort to get reasonable performance, but being a compromise with the other AM antennas on the same masts, the outcome is less than satisfactory.

As stated by other posters, the MW/AM relays are in areas where the main Droitwich 198 kHz service is poor. The MW outlets provide the LW programme service, so you will get the shipping forecast and cricket Test Match Special on the MW frequencies.

[AnalogueScott]

I live in Thurrock, Essex. Radio 4's LW reception is crystal clear here, even at night time. The 720 MW frequency isn't so good although that is more intended for London.

[Mark C]

Originally Posted by graham_moreton

Drive the pretty route into Scotland along the A38 from Corbridge northwards to the Scottish border at Carter Bar, with your car radio tuned to Radio-4 Long Wave 198 kHz.,

The A38 stops somewhere in Notts, you mean the A68 ?

[graham_moreton]

Originally Posted by Mark C

The A38 stops somewhere in Notts, you mean the A68 ?

Sorry Typo.

Yes its the A68.

Graham Moreton

[Redcoat]

198kHz here suffers from receiving the same programme from Droitwich and Westerglen at the same time, giving an uncomfirtable "echo" effect that is hard to listen to. As a result, the 774kHz transmitter from Enniskillen officially covers my area.

Oddly enough yesterday I was sitting in a car park in Belfast when I could hear the test match special on 1440kHz. Figured out that it was a second harmonic from Lisnagarvey (720kHz).

[Powerplay]

You may be interested to know that people that live with in close proximity of the Droitwich 500Kw mast have experienced light bulbs in the loft lighing up without the aid of any electricity! Thats some energy!

[David Parr]

Originally Posted by Powerplay

You may be interested to know that people that live with in close proximity of the Droitwich 500Kw mast have experienced light bulbs in the loft lighing up without the aid of any electricity! Thats some energy!

Some years ago a man was prosecuted for "stealing electricity" from Droitwich. He lived close by, and had contructed a large coil in his garden to power something or other. Unfortunately (for him!) he was detected because he cast a large shadow of reduced reception, and was easy to trace.

Stealing electricity was the only thing they could do him for at the time!

[Martin Phillp]

I live in south London and can get 720 AM and 198 LW fine, although I can understand why the BBC have the AM relay for parts of the city which can't get good LW reception.

[Yagi Bare]

Originally Posted by David Parr

Some years ago a man was prosecuted for "stealing electricity" from Droitwich. He lived close by, and had contructed a large coil in his garden to power something or other. Unfortunately (for him!) he was detected because he cast a large shadow of reduced reception, and was easy to trace.

Stealing electricity was the only thing they could do him for at the time!

I believe that's an urban myth.

It's like saying the more solar panels we use the darker it will be nearby.

[redcar1]

I find that the 603kHz service sounds better here than 198kHz - louder and clearer, despite the fact that the LW signal is OK. This is the opposite to the situation with RTE Radio 1, which sounds similarly louder and clearer on its LW frequency even though the signal strengths are similar.

[chunkymagmonkey]

I was at Dundee University between 1975 & 1979, before the BBC started transmitting Radio 4 from Westerglen and could receive a reasonable signal on 198khz from Droitwich. This begs the question about whether the Westerglen transmitter is actually required.

The cessation of transmissions from Westerglen would eradicate the "mush" conditions, which exist in North East England and mean that the medium wave transmissions of Radio 4 from Wrekenton and Carlisle could be discontinued.

What do people think?

[DVB Cornwall]

Shipping Forecasts are transmitted on 198 kHz - Therefore it's needed to be generally available. Removing Westerglen would deprive mariners of this useful service.

[Rob793]

Originally Posted by Bluenile

Plymouth 774 1kW

Redruth MF 756 2kW

At one point, weren't these frequencies used for Today South West, a separate breakfast news programme prior to the launch of BBC Radio's Cornwall and Devon?

[Bluenile]

Originally Posted by redcar1

I find that the 603kHz service sounds better here than 198kHz - louder and clearer, despite the fact that the LW signal is OK. This is the opposite to the situation with RTE Radio 1, which sounds similarly louder and clearer on its LW frequency even though the signal strengths are similar.

Probably due to RTE using a state of the art Optimod 9200 processor on 252 whereas Radio 4 on 198 sounds like it's using something that's decades old.

http://www.digitalspy.co.uk/forums/s...hlight=rte+252

603 is probably using a more up to date processor than 198 as well.

[Rakim]

Originally Posted by Emily Moor

At one point, weren't these frequencies used for Today South West, a separate breakfast news programme prior to the launch of BBC Radio's Cornwall and Devon?

I believe all Radio 4's/Home Service transmitters carried local opt-outs in the years before BBC local radio. Of course back then Radio 4 was on MW, not LW (the Light Programme/BBC Radio 2 used 200kHz/1500m up until November 1978).

Some of the old Radio 4/Home Service MW masts are no longer in use. For example Cromer in Norfolk is no longer used, with transmissions transferred to Postwick during the early 1980's. I believe Ramsgate and Bartley are other sites no longer in use now.

See also http://tx.mb21.co.uk/info/bbc-am/bbc-am.asp and http://freespace.virgin.net/mymail.a...6/trans56.html

[Rakim]

Originally Posted by Bluenile

Probably due to RTE using a state of the art Optimod 9200 processor on 252 whereas Radio 4 on 198 sounds like it's using something that's decades old.

http://www.digitalspy.co.uk/forums/s...hlight=rte+252

603 is probably using a more up to date processor than 198 as well.

It may also have something to do with the 252 Optimod being set up to give it more punch and loudness, where as the 198 Optimod is set up for speech only, meaning it would sound softer.

[David Parr]

Originally Posted by Yagi Bare

I believe that's an urban myth.

It's like saying the more solar panels we use the darker it will be nearby.

No it was true. You would have to be close to the TX for it to work. I did a similar experiment at college.

[Spot]

Originally Posted by Rakim

I believe all Radio 4's/Home Service transmitters carried local opt-outs in the years before BBC local radio. Of course back then Radio 4 was on MW, not LW (the Light Programme/BBC Radio 2 used 200kHz/1500m up until November 1978).

Some of the old Radio 4/Home Service MW masts are no longer in use. For example Cromer in Norfolk is no longer used, with transmissions transferred to Postwick during the early 1980's. I believe Ramsgate and Bartley are other sites no longer in use now.

See also http://tx.mb21.co.uk/info/bbc-am/bbc-am.asp and http://freespace.virgin.net/mymail.a...6/trans56.html

Radio 4 was always broadcast from Postwick (on 276 metres) but you're right, there was also another transmitter, called Cromer although I believe the mast was nearer Holt, which was taken out of service at the time of the wavelength changes in 1978. It used 434 metres which is now (more or less - adjusted for the small change in frequency) used by Postwick for Five Live. In fact, I can remember Postwick testing this new transmitter, then of-course assigned to Radio 2, just prior to it going into service officially, and I wondered how it might be interfering with the Cromer transmitter which was then in its final days of service.