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UK Broadcast Transmission |
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THE TRANSMISSION GALLERY
ROWRIDGE
| Photos by TCPD | Page last updated: 2012-06-18 |
| Photos taken before the removal of the original VHF antennas and replacement by a new mixed polarisation FM antenna. |
| Band I antenna and top half of Band II slotted cylinder. The Band I antennae are Marconi "Compensated Dipoles". This type was also used at Tacolneston (with horizontal rather than vertical polarisation) and at Rowridge replaced the original four tiers of single vertical dipoles that had been installed when the mast was built. The new six dipole aerial improved the HRP and allowed the erp to be raised from 32 to 100 kW without spilling additional power southwards across the Channel. |
| A diagram from a BBC Technical Instruction manual explains that "this aerial is essentially a susceptance-compensated half-wave dipole which is centre-fed through a balun arrangement from a coaxial feeder. Like the folded dipole and folded slot the compensation of this dipole is an inherent feature of the mechanical construction". |
| Standing on the platform above the Band I array, on the NNW side of the mast. |
| The lowest two slots of the Band II antenna |
| Receiving antennas |
| Inside we see the arrangement of switches connected to the band II antenna. Cables coming in from the top are the channel combiner outputs. The outputs to the antenna upper and lower halves are only just visible coming out of the back of the middle switches and going through the panel in the wall. Water cooled test loads complete with thermometers and flow meters (for power measurement) are at each end. Each set of transmitters could be connected to either half of the antenna or a load. Each antenna could be connected to either transmitter or a test port. This was a standard arrangement at high power band 2 stations, but was not replicated on the replacement mixed polarisation systems. |
| 1kW amplifier for the local radio service, BBC Solent ("LRA" in BBC code). The small bay to the left has a "Redifon" tag. May be a low power reserve transmitter, which would fit in with there being a a coaxial switch on top of the main amplifier. |
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