christian hülsmeyer

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Christian HlsmeyerFrom Wikipedia, the free encyclopedia

Christian Hlsmeyer (Huelsmeyer) (25 December 1881 31 Januar 1957) was a

German inventor and entrepreneur. He is often credited with the invention of radar, but

his apparatus, called the "Telemobiloscope," could not directly measure distance to a

target and thus does not merit this full distinction. The Telemobiloscope was, however,

the first patented device using radio waves for detecting the presence of distant objects.

Contents

1 Background

2 The Telemobiloscope 3 Post-Telemobiloscope activities

4 References

5 Other references

Background

Hlsmeyer was born at Eydelstedt, a village in Lower Saxony, Germany. He was the

youngest of five children of Johann Heinrich Ernst Meyer and Elisabeth Wilhelmine

Brenning. His birth name was Johann Christel, but after early childhood the name

Christian was used. Following completion of the local Volksschule (elementary school),

he attended Grundschule (primary school) in nearby Donstorf. A teacher there recognized

his capabilities and, in 1896, assisted him in gaining admission to theLehrerseminare

(Teacher Training College) in Bremen. At the school, his major interest was in physics,

and, after classroom hours, he was allowed to use the physics laboratory for his own

experimenting. His interest was more with the potential applications of physics than with

the academic side.[1]

In June 1900, Hlsmeyer left college without completing his studies and obtained a job as

an electrical trainee in the Siemens & Halske factory in Bremen. There he learned how

concepts of devices were turned into commercial applications, intensifying his inventive

nature. In April 1902, he left employment with Siemens to live with his brother Wilhelm

in Dsseldorf and pursue his ideas for electrical and optical products. His brother initially

funded him in setting up a shop where, a number of ideas were quickly turned into

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working items. These included a device (called a Telephonogram) that telegraphed

sounds; an electro-optical system for turning a truck into a mobile, multi-faced billboard;

and a wireless apparatus for remotely igniting explosives. Within a year, he filed several

patent applications on these and other inventions.[2]

The Telemobiloscope

In developing the wireless apparatus, Hlsmeyer read of Heinrich Hertzs discovery that

electromagnetic waves were reflected from metallic surfaces. He then turned his full

attention to using the Hertz phenomenon in a system for preventing collisions between

ships. Giving the name Telemobiloskop (Telemobiloscope) to the system, he made a

patent application on 21 November 1903, and also advertised for a financial backer.

Henry Mannheim, a leather merchant in Cologne, responded, and in March 1904,

invested 2,000 Marks for 20 percent of future profits from the apparatus. The firm

TelemobiloskopGesellschaft Hlsmeyer & Mannheim was opened the following Mayand officially registered in Cologne on 7 July 1904.

Hlsmeyers initial patent application for the Telemobiloscope was rejected, but a

refiling, dated 30 April 1904, was accepted, resulting in Patent Publication DE 165546.

An article on the system was published in a British technical magazine.[3]

The Telemobiloscope was primarily a spark-gap transmitter connected to an array of

dipole antennas, and a coherer receiver with a cylindrical parabolic antenna that could

rotate 360 degrees. While the transmitted signal had a broad coverage, the receivingantenna was narrowly focused. When a reflected signal reached the receiver, a relay was

actuated and, in turn, rang an electric bell. The basic patent description is as follows:

Hertzian-wave Projecting and Receiving Apparatus Adapted to Indicate or Give Warning

of the Presence of a Metallic Body, such as Ships or Train, in the Line of Projecting of

such Waves.

The system included a mechanism synchronizing the aiming direction of the receiving

antenna with a compass-like indicator; it also included a means of rejecting false signals.

Although the Telemobiloscope could not directly indicate range, a separate patent (DE

169154) was granted 2 April 1906, showing a method of using two vertical

measurements and trigonometry to calculate approximate range. A relatively detailed

description of the Telemobiloscope system, including a copy of the patent, is contained in

a paper by Bauer.[4]




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The first public demonstration of the Telemobiloscope was in the courtyard of the Dom

Hotel in Cologne on 17 May 1904. The metal gate to the courtyard was the target, and the

transmission path was through a curtain showing that the apparatus could work when

the target could not be seen. The demonstration was reported widely in newspapers, one

giving a detailed description.[5]

A conference was held in June 1904, at Scheveningen, the Netherlands, involving the

major shipping firms of the region; ship safety was a major topic. After learning of the

demonstration at the Dom Hotel, the head of theHolland-Amerika Lijn (HAL) invited

Telemobiloskop-Gesellschaftto provide a demonstration of their apparatus during the

conference. This demonstration took place on 9 June during a tour through the harbor at

Rotterdam aboard the ship-tenderColumbus. The Minutes of the conference (contained in

the HAL Archives in the Municipal Archives of Rotterdam) include the following

description of the demonstration:[6]

The trial on board of the Columbus, though on very limited scale and with anunfinished apparatus, proved that the principle of the inventor is correct. Every timewhen, even at certain distance, a vessel passed, the apparatus operated immediately.

ewspapers carried articles about the demonstration, all giving praise to the new

maritime safety invention. One of these closed the article with the following: Because,

above and under water metal objects reflect waves, this invention might have significance

for future warfare.[7]

The building of the Telemobiloscope and its demonstrations had depleted the initial fundsof the TelemobiloskopGesellschaftfirm. On 12 August 1904, rights to the system were

sold to Trading CompanyZ.H. Gumpel daselbstof Hannover. The sales agreement, to

which Heinrich Mannheim was a signer, said that Hlsmeyer would be given up to 5,000

Marks for future research, and 45 percent of net profits from future sales. It noted that the

previous agreement with Mannheim was then obsolete, and after Hlsmeyer has provided

proof of the usefulness of his invention, the Gumpel Company would establish a

Consortium to commercialize the invention. It also noted that If the Telemobiloscope

rights were in turn sold by Gumpel, the sales price would have to exceed 1,000,000

Marks.[8]

Improvements were made on the equipment, particularly in extending the operational

distance. Patent applications on the Telemobiloscope were filed in a number of countries.

The application in Great Britain was granted in only 10 weeks, but most of the others

were either withdrawn, rejected, or not processed because fees were not paid.




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A request was made to Holland-America to allow a demonstration at sea; this was

apparently turned down but another demonstration was given near the Hook of Holland

in the autumn of 1904. A second conference of the shipping firms was held in London in

June 1905; the Conference Minutes include the following:[9]

The Telemobiloscope: A new trial at the Hook of Holland had been a failure. One ofthe delegates reported also that the principle on which the apparatus is based has

been proven to be in error, so that probably nothing more will be heard of it.

With the distribution of these Minutes in the European shipping community, the prospect

of the Telemobiloscope as a viable product ended. There have been many explanations as

to the failure; these mainly cite either poor equipment design or the competition of

Marconi. The Telemobiloscope design used wireless technology of the late 1890s, and

did not include tuning circuits for frequency selection. By 1904, there were many

wireless sets aboard ships and at shore stations, and, without tuning capability, these

could not be rejected and thus interfered with the Telemobiloscope operation. As tocompetition, Marconis Wireless Telegraph Company dominated Europe and had

agreements with essentially all shipping firms prohibiting their use of anything except

Marconi equipment.

The Official Registry in Cologne shows that the TelemobiloskopGesellschaft Hlsmeyer

& Mannheim firm was dissolved 5 October 1905.[10]

Also, the agreement with Gumpel to

establish a Consortium for commercializing the invention would no longer be applicable.

Post-Telemobiloscope activities

In 1904, while still heavily engaged with the Telemobiloscope, Hlsmeyer filed for a

patent (DE180009) on a machine for diameter reduction of metallic rods and tubes, and

in 1906, established a firm supplying equipment for producing incandescent lamps. This

was followed in 1907 by his forming the companyKessel-und Apparatebau Christian

lsmeyer(Boilers and Apparatus Construction) in Dsseldorf; in 1910, he bought a

factory site at Dsseldorf-Flingern for the firm. For many years, this company built steam

and water apparatus, high-pressure gauges, and anti-rust-filters (trade named Rostex).

The company continued to operate until 1953. Altogether in his career, Hlsmeyer

developed and patented some 180 inventions; these and his various businesses ultimately

brought him financial success.[11]




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Although there is controversy about his inventing radar, Christian Hlsmeyer is still held

in high esteem in Germany. In January 1982, Professor K. Mauel gave a lecture at the

Organization of German Engineers Center in Dsseldorf on Radar History, celebrating

the centenary of Hlsmeyers birth. At the 2002 EUSAR Conference in Cologne, the

keynote speech was "Hlsmeyer The Inventor of Radar."[12]

During a radar conference held in Frankfurt in 1953, Hlsmeyer and Robert Watson-Watt

were honored guests. (Watson-Watt had been a leader of radar technology development

in Great Britain, and received a patent on the system in 1935). In a discussion with

Hlsmeyer as to who was the rightful inventor of this technology, it is said that Watson-

Watt ended the discussion by remarking, I am the father of radar, whereas you are its

grandfather.[13]

On 29 October 1910, Christian Hlsmeyer married Luise Petersen of Bremen. Between

1911 and 1924, they had six children. One of these, a daughter named Annelise

Hlsmeyer-Hecker, maintained collection of documents related to her father, and was a

source of much that has been written concerning him. She was also instrumental in

collecting items, including components of the Telemobiloscope, that are now displayed in

theDeutsches Museum Munic. Upon his death in Ahrweiler on 31 Jan. 1957, Christian

Hlsmeyer was buried in the North Cemetery at Dsseldorf.[14]

References

1.^

Whos Who (Germany); Christian Hlsmeyer;http://www.whoswho.de/templ/te_bio.php?PID=2187&RID=1&PHPSESSID=e6abb67664f8ebfda2cb3136dd35f8a1

2. ^ Bauer, Arthur O.; Christian Hlsmeyer and about the early days of radar inventions,Foundation Centre for German Communications and Related Technologies;http://aobauer.home.xs4all.nl/Huelspart1def.pdf

3. ^ The Telemobiloscope,Electrical Magazine (London) Vol 2, 1904, p. 3884. ^ Bauer, op. cit., pp. 16-185. ^ Die Telemobiloskop,Klner Tageblatt, Cologne, 18 May 1904

6. ^ Bauer, op. cit., p. 357. ^ Ship collision avoidance instrument,De Telegraaf(evening edition), Amsterdam, 11

June 1904

8. ^ Bauer, op. cit., p. 399. ^ Bauer, op. cit., p. 47

10. ^ Bauer, op cit., pp. 60-61

11. ^ Bauer, op. cit., p. 7012. ^ Joachim Ender; 98 Years of the Radar Principle: The Inventor Christian Hlsmeyer;

http://www.design-

technology.info/resourcedocuments/Huelsmeyer_EUSAR2002_english.pdf13. ^ Bauer, op. cit.', p. 73




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