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Jodrell Bank

Page history last edited by Alan Hartley-Smith 8 months ago

Charivaria

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Introduction

This all started with a posting to MOGS by Brian Partridge:

 

You might like to know that I spent a day at Jodrell bank helping to install a new transmitter. Apart from having to crawl through one of the cable ducts because I was the smallest one there I got the opportunity to go into the  bowl as it was in the parked upright position. We had to take a security token  to show that we were on the bowl and then wandered around this massive dish  observing the antenna mast (180ft) in the middle. We were told the story about  when some aerial parts were melted when the dish pointed at the sun for a short  while, well it was at the focus of the dish!!!. They were about to invert the  bowl when we came off and nearly did so with one of our party still there, he  had not taken the token. Whilst inverted it relied solely on the servo systems to stay in one place as there was no braking in that attitude, there was only  one man allowed to do this exercise (a senior man from the servo company). We  also met Prof Lovell who was a very eccentric chap !!!  This was a great experience for an apprentice and was also the first time I had ever been north of Rugby.

 

Followup

Bernard de Neumann

On the Radio Telescope front, when the company was the Marconi Wireless Telegraph Co, which it was when I joined in 1961, there was considerable involvement of Research Division (Gt Baddow) in the development of the Jodrell Bank Mark 1 (250 feet in diameter). My late uncle, Eric Dixon, often travelled to the site I remember, however I don't know what his involvement was.

 

Don Halstead picked up on this

While following up Bernard de Neumann's post about his uncle Eric Dixon he came across an article in the Royal Society's archives entitled "Diversions of a radio telescope" co-authored by Bernard Lovell, in which he describes the use of the 250-foot dish and a Marconi transmitter to create an ICBM early warning system capable of detecting a 10 cm square target at a range of 500 km. The following is a quote:

"On 16 May 1958 E. H. Truefitt, deputy scientific advisor to the Air Ministry, visited Jodrell Bank to discuss the possible use of the telescope to detect ballistic missiles in the event of an emergency. He felt, at first, that a serious interruption to our astronomical research would not be justified. However, he wrote on 16 October 1958 to report that at a meeting chaired by Air Vice Marshal D. S. Morris it was agreed that if the telescope were equipped with a powerful radar transmitter that was available from Marconi, valuable information could be obtained on the background of echoes from meteor trails and aurorae. This would be an extension of our existing meteor research programme but was not, as yet, a proposal to use the telescope as a defence radar. The Marconi transmitter that was installed on the telescope did indeed create a powerful radar system. The klystron transmitter produced 100 kW of peak power on frequencies of 300 or 500 MHz, using a pulse length of 170 μs and a repetition frequency of 50 Hz. With this system the 250-foot telescope could detect a 10 cm target at a range of 500 km. Reception was carried out with two orthogonal polarizations. The results were recorded by photographing cathode-ray tubes on continuously moving 35 mm film".

 

A posting (on 4th Oct 2017) on a blog celebrating that events related to this activity happened sixty years ago.

 

There are also a couple of relevant entries in the Jodrell Bank Heritage blog  1.  2.(scroll down to October entries)

 

There are also references to later use as an OTHR related to the Ballistic Missile Early Warning System (BMEWS) to be built in Britain. Work at RAF Fylingdales was proceeding slowly and  it was realised that the only way of detecting ballistic missiles in the short-term was to turn Jodrell Bank into a powerful over-the-horizon radar. The project was given the code-name Changi(later changed to Verify). Further details are being sought.

 

Further Details

Courtesy of David Emery

This is not a subject I have researched personally, but it does crop up in various books and theses - often in a similar context to OTHR. I believe that the activity to install a new transmitter described by Brian Partridge is in fact Project Verify, and the plan was to detect missile launches line-of-sight, not over the horizon. Agreement to proceed on the project was made in Dec 1960 (though had been under discussion and limited experimentation* for some years prior to this). The system would only have been used on "strategic alert", handover to the RAF supposedly taking less than 1 hour. The system was limited to pointing at an area of known launching sites.

 

Installation of the equipment was complete by April 1962, being designed by RAF West Ruislip. Transmitter may have been Type 1365 (wartime GEE Tx??). Project codename changed to Lothario (Sept 1962) but this was compromised so changed again to Changlin (Oct 1962). Testing limited to aircraft trials and satellite detection. Ceased to be used Sept 1963, and Fighter Command seemed only too happy to be rid of it, stating it was of limited operational value.

 

[* 1958 Ministry of Supply contract to make low power Tx modifications at Jodrell Bank]

 

So I think the OTHR element is a bit of a red herring - but a very interesting story nonetheless

 

Other references  1. 2.

 

I have dug up some more information of relevance. In his occasionally inaccurate book on the history of U.K. air defence, Jack Gough discusses some work undertaken in the late 50s on the defence against ballistic missiles. A five year research programme was approved in 1956, with 1/4 of a million pounds allocated to the research element via the Ministry of Supply. RRE did some initial analysis and then contracted work to Marconi for the development of a klystron transmitter and antenna design. In parallel a research contract was given to the University of Manchester to use Jodrell Bank to provide information on the occurrence of meteor trails and the Aurora Borealis on the radar false alarm rate (mentioned previously). This could explain Marconi liaison with Jodrell Bank around this time.

 

Late 1958 the U.K. was invited to cooperate with BMEWS, and this then led to the Marconi anti ballistic missile work being abandoned (though work on the klystron continued).

 

Details of the radar modifications to Jodrell Bank are slightly inconsistent across sources I have access to, but seem to be along the lines of:

 

1957 - radar tracking of Sputnik. 120 MHz, 500W mean (converted GL mark 2 Tx?).

1958 - ministry of supply contract for Anti-BM investigations. 500MHz, 1kW mean.

1962 - Project Verify/Lothario/Changlin - backup anti ballistic missile detection system (for emergency use only). Modified type 1365 (23cm/L-band) transmitter, modified type 61 console, Racal receivers. 

 

 

Charivaria

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Comments (1)

Ian Gillis said

at 5:27 pm on Feb 11, 2016

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