So, in theory then, rather than the "Scorched Earth" policy of the nationals transmitting at 250Kw, better coverage could have been achieved using less power with more masts?
So, in theory then, rather than the "Scorched Earth" policy of the nationals transmitting at 250Kw, better coverage could have been achieved using less power with more masts?
Yes, and/or better height. Some BBC national FM transmitters have the aerials in woefully low positions on the masts (Rowridge, Pontop) Even the new mast at Rowridge has the FM aerials exactly at the same height as the old (precedent obviously set with the French over interference levels), Lower power but from a higher number of higher masts might have been better, and been cheaper overall because fewer relays might have only been necessary.
Yes, and/or better height. Some BBC national FM transmitters have the aerials in woefully low positions on the masts (Rowridge, Pontop) Even the new mast at Rowridge has the FM aerials exactly at the same height as the old (precedent obviously set with the French over interference levels), Lower power but from a higher number of higher masts might have been better, and been cheaper overall because fewer relays might have only been necessary.
(All speculation BTW)
Interesting stuff. It's kind of odd, in a way, when you look at the number of transmitters used by the Nationals, the overlaps in some areas are 6, 7 or 8 different frequencies. Yet, here as the OP was saying, some areas are poorly served, by poor planning years ago I guess.
Interesting stuff. It's kind of odd, in a way, when you look at the number of transmitters used by the Nationals, the overlaps in some areas are 6, 7 or 8 different frequencies. Yet, here as the OP was saying, some areas are poorly served, by poor planning years ago I guess.
To be fair the network we have today is constrained by the way it was designed in the 1950s, the same as TV, for reception by outdoor roof top aerials. Then in the 80s, the
requirement was for mobile reception by portables and car radios. Mixed polarization came along (that helped up to a point) but there was also a surge in the 80s and 90s in new medium (Ridge Hill, Chatton, Winter Hill) and low power relays
To be fair the network we have today is constrained by the way it was designed in the 1950s, the same as TV, for reception by outdoor roof top aerials. Then in the 80s, the
requirement was for mobile reception by portables and car radios. Mixed polarization came along (that helped up to a point) but there was also a surge in the 80s and 90s in new medium (Ridge Hill, Chatton, Winter Hill) and low power relays
Might not been a factor when the Sold Coldfield site was chosen but many transmitting stations are also there to feed other sites, either as their main feed or as a reserve for other main stations.
Lots of lower sites might give better coverage in some areas but then there are the problems of chosing channels to use which will get more complicated. Also reception in cars would have been messier in the days before RDS.
It's the opposite of the suggestion that we used to hear - why not put one high power transmitter on the summit of Ben Nevis to serve the whole of Scotland. It was not worth wasting time trying to explain why not.
It's the opposite of the suggestion that we used to hear - why not put one high power transmitter on the summit of Ben Nevis to serve the whole of Scotland. It was not worth wasting time trying to explain why not.
Indeed !
Although I've just returned from New England, where we went up Mt Washington, 6288 ft above sea level. Up there, there's the FM transmitter for a radio station WHOM that serves New Hampshire, Maine, and bits of Vermont. It's 50 kW, and has a huge range, we drove around all three states, and it was receivable over a large area. Multipath was only really noticeable in the valleys very close to the site. I was surprised how good the signal was
Quite an interesting history about the site, Mr Armstrong himself (the inventor of FM radio ) conducted his tests up there in the 1930s
I'd imagine reception of RH isn't too good in Cheltenham, because of Churchdown Hill itself (the hill not the Tx !)
There's actually a FM deadspot right in the middle of Cheltenham as you go down from the Queens Hotel towards the Promenade. My car radio loses DAB there too.
Lichfield and Sutton are 4 miles apart, and not much difference in height.
I imagine coverage would be near identical.
Channel 5 reception was really good here, while Sutton was always slightly grainy. The Derbyshire multiplex also seems to get out really well from Lichfield, I've received it in Nantwich and Oswestry!
Yes, and/or better height. Some BBC national FM transmitters have the aerials in woefully low positions on the masts (Rowridge, Pontop) Even the new mast at Rowridge has the FM aerials exactly at the same height as the old (precedent obviously set with the French over interference levels), Lower power but from a higher number of higher masts might have been better, and been cheaper overall because fewer relays might have only been necessary.
(All speculation BTW)
Off topic I know, but interesting to read on MB21 that the BBC thought Rowridge's performance was 'not entirely satisfactory'! (Link here:http://downloads.bbc.co.uk/rd/pubs/reports/1958-26.pdf). Looks like that site was chosen to primarily serve the cities of Southampton & Portsmouth, the main population parts of the area. I don't know that area well enough to comment on Rowridge's coverage, but I've always been impressed by the coverage of the stations from Chillerton Down, notably the 100 watt signal from Isle of Wight Radio!
Off topic I know, but interesting to read on MB21 that the BBC thought Rowridge's performance was 'not entirely satisfactory'! (Link here:http://downloads.bbc.co.uk/rd/pubs/reports/1958-26.pdf). Looks like that site was chosen to primarily serve the cities of Southampton & Portsmouth, the main population parts of the area. I don't know that area well enough to comment on Rowridge's coverage, but I've always been impressed by the coverage of the stations from Chillerton Down, notably the 100 watt signal from Isle of Wight Radio!
Yes, Wave 105.2 from Chillerton goes further than BBC Solent from Rowridge. Both are 10kW ERP, but Wave's antenna is hundreds of feet higher than Solent's.
Of course Chillerton's original use was high power Band III ITV for Southern England,
and it successfully mangaed to match Band I BBC 1 coverage from Rowridge.
A shame it wasn't selected for UHF TV or FM moved there, (remember the Beeb relocated their FM transmissions from Kirk-O Shots to Black Hill in the 80s).
Chillerton's mast is very slender (difficult to even see it from the main land) so
it probably couldn't have supported a UHF cylinder as well as the Band III stack.
I'd imagine reception of RH isn't too good in Cheltenham, because of Churchdown Hill itself (the hill not the Tx !)
I'm not sure actually! I'll have to check next time I'm down that way. Ridge Hill certainly seems to be the transmitter for TV reception there so line of sight can't be too obstructed. There did used to be an analogue Channel 5 relay on Churchdown for Cheltenham but I think that was more because of the fact that both Ridge Hill and The Wrekin were co-channel on channel 35 and both receivable in the same sort of direction from there, causing bad CCI.
I suppose the fact it exists as a BBC FM relay must mean it's needed but it's interesting that one was provided there and not for the large swathes of Worcestershire, Stoke and Nottingham that get poor reception.
I'm not sure actually! I'll have to check next time I'm down that way. Ridge Hill certainly seems to be the transmitter for TV reception there so line of sight can't be too obstructed. There did used to be an analogue Channel 5 relay on Churchdown for Cheltenham but I think that was more because of the fact that both Ridge Hill and The Wrekin were co-channel on channel 35 and both receivable in the same sort of direction from there, causing bad CCI.
I suppose the fact it exists as a BBC FM relay must mean it's needed but it's interesting that one was provided there and not for the large swathes of Worcestershire, Stoke and Nottingham that get poor reception.
Well, Churchdown Hill has been an FM relay since 1965 ! I suspect someone important from the BBC must have lived locally.
As for C5, it was there before Ridge Hill and The Wrekin. It was one of the original launch transmitters, Ridge Hill and Wrekin came along in Phase 2, so I'm not sure it was to specifically plug the CCI problem those had
Well, Churchdown Hill has been an FM relay since 1965 ! I suspect someone important from the BBC must have lived locally.
As for C5, it was there before Ridge Hill and The Wrekin. It was one of the original launch transmitters, Ridge Hill and Wrekin came along in Phase 2, so I'm not sure it was to specifically plug the CCI problem those had
More likely a cheap & cheerful way of getting C5 to the affluent population of Cheltenham for advertisers.
Well, Churchdown Hill has been an FM relay since 1965 ! I suspect someone important from the BBC must have lived locally.
As for C5, it was there before Ridge Hill and The Wrekin. It was one of the original launch transmitters, Ridge Hill and Wrekin came along in Phase 2, so I'm not sure it was to specifically plug the CCI problem those had
Channel 5 roll out was badly mishandled in Worcester (and maybe everywhere else; Worcester is just where I happened to be). Much of the city is covered by Malvern, with odd patches from Sutton and Bromsgrove and the odd few houses from Ridge Hill and the Wrekin. Only the few on Sutton got C5 initially. Before phase 2, the city was flyered in the local press, claiming coverage was coming to Worcester. In fact, this referred to Ridge Hill and the Wrekin only; Malvern and Bromsgrove never got C5 analogue. So, twice people in Worcester had been expecting Channel 5 to just appear, and twice it failed to do so. The retuners who came house to house prior to phase 1 roll out either had no idea that most Worcester folk weren't actually going to receive C5, or they had been instructed not to say so.
They could do with a relay on Malvern (or somewhere that would serve Worcester - especially the low lying city centre areas) as well!
Since this is turning into one of those favourite DS "fantasy planning" threads :-) I've wondered whether it might have been better to put a radio relay on Malvern rather than a TV one. As others have said, the lack of a relay for the FM nationals has always made reception in Worcester very ropey, whereas Wyvern and BBC H&W from Malvern always boomed in. Meanwhile, I'm wondering if those served by the Malvern and Bromsgrove TV relays couldn't actually have been covered by one single site somewhere in between, since Malvern radiates northwards of the Malvern Hills and Bromsgrove radiates southwards of the Lickeys?
There is a comparison map halfway down the page which shows the measured 2kW Lichfield service and the estimated 10kW SC service.
It looks as if the area that changed the most is to the north and west, although must have also given a stronger signal in Birmingham city centre
So, in theory then, rather than the "Scorched Earth" policy of the nationals transmitting at 250Kw, better coverage could have been achieved using less power with more masts?
I said something similar earlier. It seems that the network was planned in the 1950s when people had outside VHF aerials and as time has gone on, things have changed and the network is still as it was (pretty much)
I said something similar earlier. It seems that the network was planned in the 1950s when people had outside VHF aerials and as time has gone on, things have changed and the network is still as it was (pretty much)
This group's DX enthusiasts will tell us, but I think 250kW FM transmitters are rare elsewhere in Europe ?
Comments
So, in theory then, rather than the "Scorched Earth" policy of the nationals transmitting at 250Kw, better coverage could have been achieved using less power with more masts?
Yes, and/or better height. Some BBC national FM transmitters have the aerials in woefully low positions on the masts (Rowridge, Pontop) Even the new mast at Rowridge has the FM aerials exactly at the same height as the old (precedent obviously set with the French over interference levels), Lower power but from a higher number of higher masts might have been better, and been cheaper overall because fewer relays might have only been necessary.
(All speculation BTW)
Interesting stuff. It's kind of odd, in a way, when you look at the number of transmitters used by the Nationals, the overlaps in some areas are 6, 7 or 8 different frequencies. Yet, here as the OP was saying, some areas are poorly served, by poor planning years ago I guess.
To be fair the network we have today is constrained by the way it was designed in the 1950s, the same as TV, for reception by outdoor roof top aerials. Then in the 80s, the
requirement was for mobile reception by portables and car radios. Mixed polarization came along (that helped up to a point) but there was also a surge in the 80s and 90s in new medium (Ridge Hill, Chatton, Winter Hill) and low power relays
Might not been a factor when the Sold Coldfield site was chosen but many transmitting stations are also there to feed other sites, either as their main feed or as a reserve for other main stations.
Lots of lower sites might give better coverage in some areas but then there are the problems of chosing channels to use which will get more complicated. Also reception in cars would have been messier in the days before RDS.
It's the opposite of the suggestion that we used to hear - why not put one high power transmitter on the summit of Ben Nevis to serve the whole of Scotland. It was not worth wasting time trying to explain why not.
Indeed !
Although I've just returned from New England, where we went up Mt Washington, 6288 ft above sea level. Up there, there's the FM transmitter for a radio station WHOM that serves New Hampshire, Maine, and bits of Vermont. It's 50 kW, and has a huge range, we drove around all three states, and it was receivable over a large area. Multipath was only really noticeable in the valleys very close to the site. I was surprised how good the signal was
Quite an interesting history about the site, Mr Armstrong himself (the inventor of FM radio ) conducted his tests up there in the 1930s
http://www.necrat.us/whom.html
http://archives.chicagotribune.com/1941/09/21/page/184/article/mt-washington-fm-gives-wide-radio-coverage
There's actually a FM deadspot right in the middle of Cheltenham as you go down from the Queens Hotel towards the Promenade. My car radio loses DAB there too.
Channel 5 reception was really good here, while Sutton was always slightly grainy. The Derbyshire multiplex also seems to get out really well from Lichfield, I've received it in Nantwich and Oswestry!
Off topic I know, but interesting to read on MB21 that the BBC thought Rowridge's performance was 'not entirely satisfactory'! (Link here:http://downloads.bbc.co.uk/rd/pubs/reports/1958-26.pdf). Looks like that site was chosen to primarily serve the cities of Southampton & Portsmouth, the main population parts of the area. I don't know that area well enough to comment on Rowridge's coverage, but I've always been impressed by the coverage of the stations from Chillerton Down, notably the 100 watt signal from Isle of Wight Radio!
Yes, Wave 105.2 from Chillerton goes further than BBC Solent from Rowridge. Both are 10kW ERP, but Wave's antenna is hundreds of feet higher than Solent's.
Of course Chillerton's original use was high power Band III ITV for Southern England,
and it successfully mangaed to match Band I BBC 1 coverage from Rowridge.
http://tx.mb21.co.uk/info/405/itv/south.shtml
A shame it wasn't selected for UHF TV or FM moved there, (remember the Beeb relocated their FM transmissions from Kirk-O Shots to Black Hill in the 80s).
Chillerton's mast is very slender (difficult to even see it from the main land) so
it probably couldn't have supported a UHF cylinder as well as the Band III stack.
I'm not sure actually! I'll have to check next time I'm down that way. Ridge Hill certainly seems to be the transmitter for TV reception there so line of sight can't be too obstructed. There did used to be an analogue Channel 5 relay on Churchdown for Cheltenham but I think that was more because of the fact that both Ridge Hill and The Wrekin were co-channel on channel 35 and both receivable in the same sort of direction from there, causing bad CCI.
I suppose the fact it exists as a BBC FM relay must mean it's needed but it's interesting that one was provided there and not for the large swathes of Worcestershire, Stoke and Nottingham that get poor reception.
Well, Churchdown Hill has been an FM relay since 1965 ! I suspect someone important from the BBC must have lived locally.
As for C5, it was there before Ridge Hill and The Wrekin. It was one of the original launch transmitters, Ridge Hill and Wrekin came along in Phase 2, so I'm not sure it was to specifically plug the CCI problem those had
More likely a cheap & cheerful way of getting C5 to the affluent population of Cheltenham for advertisers.
Channel 5 roll out was badly mishandled in Worcester (and maybe everywhere else; Worcester is just where I happened to be). Much of the city is covered by Malvern, with odd patches from Sutton and Bromsgrove and the odd few houses from Ridge Hill and the Wrekin. Only the few on Sutton got C5 initially. Before phase 2, the city was flyered in the local press, claiming coverage was coming to Worcester. In fact, this referred to Ridge Hill and the Wrekin only; Malvern and Bromsgrove never got C5 analogue. So, twice people in Worcester had been expecting Channel 5 to just appear, and twice it failed to do so. The retuners who came house to house prior to phase 1 roll out either had no idea that most Worcester folk weren't actually going to receive C5, or they had been instructed not to say so.
Since this is turning into one of those favourite DS "fantasy planning" threads :-) I've wondered whether it might have been better to put a radio relay on Malvern rather than a TV one. As others have said, the lack of a relay for the FM nationals has always made reception in Worcester very ropey, whereas Wyvern and BBC H&W from Malvern always boomed in. Meanwhile, I'm wondering if those served by the Malvern and Bromsgrove TV relays couldn't actually have been covered by one single site somewhere in between, since Malvern radiates northwards of the Malvern Hills and Bromsgrove radiates southwards of the Lickeys?
http://www.mds975.co.uk/txmaps/westmids.html
There is a comparison map halfway down the page which shows the measured 2kW Lichfield service and the estimated 10kW SC service.
It looks as if the area that changed the most is to the north and west, although must have also given a stronger signal in Birmingham city centre
Makes you wonder why they crank the power so much given the example there, or am I missing something?
I said something similar earlier. It seems that the network was planned in the 1950s when people had outside VHF aerials and as time has gone on, things have changed and the network is still as it was (pretty much)
This group's DX enthusiasts will tell us, but I think 250kW FM transmitters are rare elsewhere in Europe ?
Yes they are, although the Marseille/Grande Etoile transmitter runs a whopping 398 kW (horizontal) for France Inter, Culture and Musiques!