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THE TRANSMISSION GALLERY

CAMBRIDGE (MADINGLEY)

Photos by Dan Glover Page last updated: 2015-08-21

August 2015: local TV

Cambridge TV launched on 18 August 2015. Two days later Dan stopped off at Madingley to see what arrangements had been made for the new station


Seen from the road immediately north of the site - the trees prevent a full view of the structure

A new array has been added for local TV but otherwise no apparent change to the broadcast antennas. Some "pruning" must have occurred as there is empty metalwork which probably supported other mobile phone antennas

At the very top is a stack of UHF dipoles, assumed to be non-broadcast, and then one of three Band II arrays. DAB is above the platform with the ex-Channel 5 panels just below. The BBC national networks use the arrangement of three logs and the new local TV array can be seen on the corner nearest the camera. Below this is a third Band II array using dipoles with reflectors. The two logs just above the trees on the right are to receive Peterborough

Now for some more detail...


The arrangement of Marconi dipoles forms a two-tier Lindenblad array which is used by BBC Cambridgeshire and what is now Heart

It's just possible to see that the tower is of a standard type designed to allow a UHF cylinder to be mounted at the top - there's a pattern of small holes around the large central hole in the top plate

The setting sun has given the Band II dipole centres a slightly orange tint - the Band III array is always brightly coloured!


The tower is square, so is the DAB array (almost), but there is an offset - maybe to optimise where the peaks and nulls in the radiation pattern will fall in terms of the intended service area?


Here's the new array for local TV - two tiers of crossed logs with shiny new metalwork

(The mottled effect on the shrouded logs is due to the light)


From a slightly different position, the local TV array merges into the background but we can see the array of logs used by the BBC national networks. We understand the vertical log is on bearing 121 and the horizontal logs on bearings 076 and 166

At the bottom of the photo (43m according to Ofcom data) is the array now used by Kiss which comprises two tiers of HP and VP dipoles plus reflectors - this has maximum ERP on bearing 090


Looking up through the BBC National array, the ex-Channel 5 analogue antenna. The lower panel isn't falling off - there is a couple of degrees of down-tilt


Detail of the lower tier of the array used by Kiss

In the background the "wrong way round" UHF yagi might be for local radio outside broadcast links - from a different angle it looks like it is on a rotator (in this photo hidden by the SHF dish)


These 18-element yagis, relatively low on the tower, appear to be facing south west - maybe to receive Channel 5? The signal could have been quite marginal since the C5 coverage was mainly north and west from Sandy Heath - hence the relay at Madingley


There's rather less doubt about the purpose of the two logs directed towards Peterborough, which is the source for the BBC National networks under normal conditions

We understand Tacolneston was used as an alternative in late 2004 when Peterborough was off-air, however there seems to be no trace now of this arrangement


Another view of the local TV array



Cambridge (Madingley) index

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