BBC RADIO CORNWALL

BBC map detailing coverage of BBC Radio Cornwall. {ILR's for Cornwall (Pirate FM etc and Atlantic FM etc) will have broadly similar coverage to Radio Cornwall, although these services are transmitted from different aerials and at slightly different power form the masts at Cardon Hill and Redruth. There is no coverage on the Scilly Isles though}

COMMUNITY RADIO FOR THE ISLES OF SCILLY  - RADIO SCILLY 107.9

The transmitter for the excellent community radio station, Radio Scilly, is at the same location, Telegraph Hill, as the BBC national and local radio transmitters. However Radio Scilly uses 100 watts with Vertical polarisation using a directional aerial, whereas the BBC services use 60 watts with mixed polarisation and with an omnidirectional radiation pattern. Plot showing predicted coverage for Radio Scilly 107.9 I must congratulate Keri Jones, the station manager, on the wonderful local sound of the new Radio Scilly. I am certain that this new station will be welcomed hugely by the people of the Scilly Isles. There was a previous question on this thread about the coverage of the new Radio Scilly transmitter from Telegraph Hill, particularly relating to the reception on the mainland. The plots for the Radio Scilly transmitter site show that reception will be quite difficult on the mainland, unless one is at the very south western extremities of Cornwall. Radio Scilly benefits from a power of 100 watts (maximum e.r.p.) with vertical polarisation from the same mast that is used by the BBC radio services. What has to be considered, though, is that Radio Scilly uses a directional aerial that is located lower down the mast than for the BBC services. Since no Ofcom data is yet published, I have had to make some assumptions for the transmission characteristics, but I don't think that they will be wildly wrong. I believe that the BBC use a nominally omnidirectional aerial situated about 71m above ground level. We know that the Radio Scilly aerial is lower down the transmission tower, so I have estimated that it might reasonably be located 50m above ground level. We also know that the Radio Scilly aerial is directional and I have therefore assumed that it would therefore be directed towards Hugh Town from the Telegraph Hill site, which would be at about 220 degrees. I have used a Cardiod Antenna model with a 10dB reduction to the rear. As far as the plots produced by the antenna plotting program are concerned, the green area represents the 54dB/uV/m signal level which is the industry standard for acceptable Stereo reception assuming that a good quality fixed receiving aerial is installed at roof height (10 meters above ground level). All radio stations use this criterion for predicting their service area. The 48dB/uV/m contour in yellow is the mono service area for the above receiving aerial conditions. In practice, of course, few listeners, unfortunately, use a stereo FM tuner connected to a decent receiving aerial mounted above roof level at a height of at least 10meters a.g.l. However given that most good quality radios these days are very sensitive, it seems that adequate reception should be available on all but the shoddiest of cheap Chinese radios across all of the islands. From practical experience I have found that a 28dB/uV/m contour demonstrates the approximate limit of reception on a car radio - albeit very hissy and noisy. The plot that I have produced on the above link shows 6dB gradations from 54dB/uV/m down to 24dB/uV/m, and it can be seen that the weaker coverage only includes a relatively small area of the mainland in coastal areas between St Levan and St Just and maybe higher ground north of The Lizard. Those listeners with good quality separates Hi-Fi tuners and roof top band II aerials directed towards the Isles Of Scilly, or with rotatable high gain band II aerials, may obtain some sort of reception further inland than this plot suggests. I may produce another one when Ofcom release the actual technical specifications of the transmission aerial system in use.

ILR PLYMOUTH - (Plymouth Sound etc)

The IBA map showing the area covered by ILR Plymouth (Plymouth Sound etc) which included a small part of Cornwall.  v.h.f. transmitters at Plympton and Tavistock and m.f. transmitter at Plumer Barracks