Tag Archives: Marconi

Bushy Hill, Essex

By Alice White

Although not an obvious tourist destination, Bushy Hill is the biggest landmark in the area of South Woodham Ferrers, Essex, and has played a notable role in the history of technology, as well as unintentionally providing natural science revelations.

From the 1950s, Bushy Hill was one of the sites used by Marconi for its radar development programme, and as a result of the prominence of this technology upon its summit, it has come to be known as “Radar Hill”. It is visible for miles around and commonly used as a navigation point for planes flying using Visual Flight Rules (VFR). Many people have therefore seen Bushy Hill, but few are aware of its interesting history.

Marconi Radar (pictured in 2006). This is one of the antennas at TQ8198 : Bushey Hill Radar near South Woodham Ferrers. Only a few short years ago the idea that Marconi would cease to exist except in name would have been unthinkable. ( © Copyright Glyn Baker, CC BY-SA 2.0)

The United Kingdom’s radar system had been rapidly run down towards the end of the Second World War, but the first Soviet nuclear test in 1949 and the beginning of the Korean War in 1950 gave a new urgency to improving air defences. Marconi won significant contracts to develop radar, and acquired the Bushy Hill site in the mid-1950s in order to carry out trials on proposed new radar technology.

Bushy Hill was selected because existing sites were “rather too good”: they were located in dips and depressions that insulated radars from noise (called “clutter” in radar terminology) caused by reflections of radar signals from unwanted sources such as the ground.* However, to improve radar performance, it was necessary to find a way of reducing clutter. Bushy Hill, with unobstructed 360˚ views, and conveniently close to the Chelmsford headquarters of Marconi radar, was the perfect site. A large, 75 feet wide antenna was installed, and used to develop a range of transmitters and signal processing systems which were sold all over the world.

Bushy Hill has a Type 80 aerial mount, which had revolutionised radar in 1953. Developed under an RAF programme with the curious title GREEN GARLIC, this system dealt with both early warning and controlling interceptions. These extra seconds of advance notice acquired greater significance with the 1955 development of the Soviet H-bomb and the existence of new supersonic bomber planes. In 1959, the Marconi Company was awarded a government development contract for a passive detection system known as WINKLE, and a high speed receiving aerial was also installed. Despite the cutting edge technology, in the early days activities at Bushy Hill were restricted to daytime-only working because of complaints that the radars interfered with television reception, as both operated on Band 1 at the time.

This military-industrial site conducting work driven by Cold War concerns would also provide unexpected research legacies for a field far removed from supersonic jets and hydrogen bombs. Clutter caused by the ground had been effectively eliminated by the development of a Moving Target Indicator (MTI), but there were still small echoes appearing, moving slowly and randomly. Due to lack of explanation for these mysterious echoes, they were dubbed “Angels”. There were two possible explanations. During the early years of World War Two, large flocks of birds had been picked up on radar, and even individual large sea birds detected – the Angels could therefore be birds. However, the behaviour of these Angels wasn’t consistent with any known bird behaviour, so it was assumed that they must be pockets of warm air generated by factory chimneys or warm roofs.

Dr Sir Eric Eastwood and a small team had a great many very early mornings at Bushy, recording the flow lines which the Angels followed using a method similar to time-lapse photography. Rings which expanded outwards at dawn, like the ripples on the surface of water when a stone is thrown in, were at first assumed to be caused by the stoking of factory furnace, but an expedition to the site showed that there were not only no factories, and no buildings at all – the location of the rings was in the middle of open countryside! A copse of trees covered with starlings revealed the cause of the strange rings of Angels: successions of waves of birds, separated by three minute intervals, took off from the roost moving in expanding circles to feeding grounds. The Bushy Hill radars also confirmed the suspected “vesper” (evening) flights of swifts, and provided information on the migration of birds.

During subsequent years, Bushy Hill has been used for the development and testing of many systems, as well as being used as a showroom to demonstrate the performance of systems to potential customers. The large radar was also used as a source of radar signals to a number of users, such as the Radar Establishment at Great Malvern, the Marconi Research Centre at Great Baddow, and the RAF at Bawdsey. The RAF used this service to monitor some of its exercises. The site is still operated by BAe Systems as a trials site, so the site itself is not open to visitors, though the surrounding hills are often used for tobogganing.

Thanks to Roy W. Simons, OBE, C. Eng., FIEE, F.I.Mgt., Chris Gardiner of the Marconi Veterans Association, and the MOGS forum for their kind assistance with this article.

*One unexplained effect of clutter was that the Dutch coast appeared to be travelling slowly towards the UK!


Further information

Dr Eric Eastwood, ‘Radar’s Contribution to Studies of Birds’, New Scientist No.282 (1962)

Jack Gough, Watching the Skies: The History of Ground Radar in the Air Defence of the United Kingdom (HMSO, 1993)

R. W. Simons & J. W. Sutherland, ‘Forty Years of Marconi Radar from 1946 to 1986’ GEC Review, Vol. 13, No.3, (1998)


Bologna, Italy

By Charles Tanford & Jacqueline Reynolds

Piazza Maggiore, Bologna

Bologna itself is an impressive city, with broad arcaded streets, many closed to private cars. It is the site of the first real university in Europe, which, politics and pestilence notwithstanding, has flourished more or less uninterruptedly to the present day. The university began as a community of professors and scholars without a permanent home (despite the presence of as many as 10,000 students), but a regular building was eventually constructed in 1563. The university remained there until 1803, when the move to its present site outside the city center was made.

The old university is in the Palazzo Archiginnasio, located on the Piazza Galvani behind the Basilica San Petronio. Escutcheons of former rectors and professors densely cover the courtyard, surrounding vestibules and staircases. Most of the building is now occupied by a modern library, but the historical parts have been restored to their original state and are open to the public. The most interesting part is the anatomical theatre, originally built in 1637, leading off a gallery overlooking the courtyard. It is a spacious rectangular room, built entirely of wood, with only three tiers of seats. Statues of Hippocrates, Galen, and other doctors/anatomists of antiquity line the wall, and there are busts of prominent local physicians. A centerpiece of the room is the lecture podium with an impressive canopy supported by statues of skinless human bodies in which the musculature is clearly exposed to view. The visitor should apply to the Porter’s lodge for admission.

Luigi Galvani and Guglielmo Marconi are well-remembered Bolognesi. There is a statue of Galvani in the piazza named after him.

Porthcurno Telegraph Museum, Cornwall

By Richard Noakes

Porthcurno telegraph cable station, April 2011

Anyone interested in the history of communication is truly spoilt for places to visit in the Cornwall. It’s got sites covering a wide range of technologies from semaphores (Lloyd’s Signal Station) and cable telegraphy (Porthcurno Telegraph Museum) to wireless (the Marconi Centre and Lizard Wireless Station) and satellite communication (Goonhilly). Most are relatively straightforward to access by public transport but do take into account long journey times: buses are not as frequent as you might expect and they often take very circuitous routes!

If you have to visit just one place, make it Porthcurno, three miles from Land’s End. It’s the only working submarine cable station in the world and also holds an enormous collection of instruments, artefacts and archival materials relating to the history of submarine cable telegraphy from the 1850s to the present day. Visit the museum and you’ll be able to see electromechanical and electronic apparatus whirring and clicking as smoothly as they did in the 1920s and ‘30s. Most are operated and lovingly maintained by former engineers of Cable and Wireless – the firm that for much of the twentieth century used the museum buildings as a cable station and training college. You should also wander round the museum’s ‘Nerve Centre of Empire’ exhibition to explore the lives and places of the men and women who helped keep Britain’s imperial telegraphic system running. And don’t forget the underground tunnels built in the Second World War to safeguard the crucial British imperial telegraphic network against enemy attack. The museum is open seven days a week, 10am-5pm. For directions and further details see http://www.porthcurno.org.uk/index.php.

Porthcurno Telegraph Museum

You can’t understand the development of cable telegraphy in the twentieth century without wireless. Maybe after visiting Porthcurno, take a trip around the coast to the Marconi Centre, on the Lizard. Run by the National Trust and the Poldhu Amateur Radio Club, it’s located on the site where Marconi’s first transatlantic wireless messages were transmitted in December 1901. The museum boasts a splendid collection of early wireless equipment, some excellent audio-visual material, and a hugely knowledgeable staff. Don’t forget to take a look at the nearby remains of the transmitting station and the memorial marking Marconi’s transatlantic achievement. The museum has rather restricted opening hours: during July it’s open on Wednesdays, Thursdays and Sundays 1.30-4.30pm, and Fridays 7-9pm. It’s best to ring 01326-241656 to arrange a visit. For directions and further details see http://marconi-centre-poldhu.org.uk.

Not far from the Marconi Centre is another Marconi site owned by the National Trust: the Lizard Wireless Station. This is the original wooden building in which Marconi and his colleagues conducted experiments. The museum displays replicas of the induction coil, spark-gap, Morse key and other equipment used by Marconi, and also houses an amateur radio station. For opening hours ring 01326-561407, and for further details see http://www.lizardwireless.org/.

Further information:

John Moyle, Cornwall’s Communications (Truro, 2009)
Wendy Gagen and David Dawson, Nerve Centre of Empire: Connecting Cornwall, Expanding Frontiers 1870-1918 (Porthcurno, 2010)