Built in 1956 the Crystal Palace transmitter tower was the tallest building in London at 728 ft until Canary Wharf was built in 1991. The BBC chose to build a freestanding ‘Eiffel Tower’ type structure as the conventional TV mast has to be guyed. This was impossible within the confines of the Park and local roads. The Tower was built on part of the site of the old aquarium and probably on the tunnel that led from the old TV studios under Crystal Palace to the North Tower before both were destroyed.
Initially built to transmit the single BBC 405 line service the tower has in the past 50 years acquired more and more tenants. Nearly all London public broadcasters transmit from the Tower with the notable exceptions of BBC Radio VHF services from Wrotham in Kent. The Church Road transmitter acts as a standby for the major channels.
The tower will became the sole hub of London’s digital services when analogue was closed in 2012. A new central shaft was built to carry new cables for the extra more powerful transmitters.
Ownership of the Tower has changed several times in the past few years. The BBC was forced to divest its transmission services by Margaret Thatcher’s Conservative Government. It was acquired by Crown Castle. Crown was then acquired by NTL who later sold it to National Grid. National Grid merged with arqiva in March 2008 and now operates under that brand and is owned by a consortium of investors and the Australian Macquarie Bank.
Crystal Palace serves more people than any other transmitter. It covers most of South East England and TV reception reaches into the East Midlands and the English Channel.
More technical information can be found here: http://www.ukfree.tv/txdetail.php?a=TQ339712
In the early 1970s there was a scare caused by an apparent cluster of cancer cases around the Sutton Coldfield transmitter near Birmingham. A study of the much more highly populated area around Crystal Palace was conducted. This showed that there was a very small decrease in the expected cases very near the transmitter (radiation is good for you?) and a small increase in a ring a few miles out. Overall nothing very significant. However it should be noted that many transmissions are now at shorter wavelengths making it a candidate for another study.