General Information

Serial #

N/A

Part Number

1

Total Parts

6

AKA

N/A

Patents

N/A

General Description

Hydrophone No. 20 manufactured by Chester Beachell. Hydrophone No. 20 produit par Chester Beachell.

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

20.0 cm

Width

N/A

Height

N/A

Thickness

N/A

Weight

N/A

Diameter

4.5 cm

Volume

N/A

Lexicon

Group

Communications

Category

Sound

Sub-Category

N/A

Manufacturer

AKA

Beachell

Country

Canada

State/Province

Ontario

City

Ottawa

Context

Country

Canada

State/Province

Quebec

Period

Hydrophone was designed and built between 1970 and 1980. It was subsequently given by Chester Beachell to his niece as a gift in 1994. L'hydrophone a été conçu et construit entre 1970 et 1980. Il a ensuite été donné par Chester Beachell à sa nièce comme cadeau en 1994.

Canada

The hydrophone No. 20 is one of several hydrophones designed and built by Canadian Chester Beachell, at the NFB in Montreal, between 1970 and 1980. No. 20 is one of the two known surviving examples of Beachell hydrophones. Hydrophone No. 20 is believed to be the last hydrophone Beachell built and represents the culmination of his work developing improved technology for underwater listening and recording. Chester Beachell was a Senior Research Officer, Technical Research Division at the National Film Board from 1951 to 1980. He participated in many projects documenting research expeditions for the NFB. Beachell wrote that “the presence of all this sound in the ‘silent world’ convinced him that he should design and build high quality hydrophones, and a recorder, which could be carried by a diver”. He designed his first experimental hydrophone in November 1970 following a request from Bané Jovanovic, the director of NFB film The Sea. He continued to develop improved hydrophone technology, resulting in underwater recordings that were used in a number of films produced by the National Film Board of Canada.

Function

Underwater microphone designed to pick up acoustic energy, or sound waves, by detecting changes in pressure in the surrounding environment and converting them into changes in electrical voltage. This hydrophone would have been powered by a 9-volt power supply and attached to a tape recorder. It may have been used with a second hydrophone in order to record in stereo.

Technical

Early hydrophones were improved for military use, primarily for the purpose of locating submarines and icebergs. Hydrophone arrays, or large groups of hydrophones positioned thousands of miles apart, were also used for navigational purposes and in military tracking and contained pre-amplifiers to limit noise contamination. In addition to military purposes, hydrophones today are used to study marine life and assist in undersea conservation efforts. The ordinary elastic bands, bimorph crystal, and protective grill are indicative of Beachell’s early work and can be seen when looking at Hydrophone No. 20. It is likely made out of “hard duraluminum” which allowed Beachell’s hydrophones to withstand pressures of at least 45atm, a depth of 1500ft and was likely coated in Verithane to protect the silver coating from the salt water.

Area Notes

Unknown

Details

Markings

Text on the flat extremity of the hydrophone: " HYDROPHONE /. NO. 20 /. CHES BEACHELL "

Missing

Appears complete.

Finish

A cylindrical shaped hydrophone made primarily from metal with a black body. The head of hydrophone has a silver coloured protective metal grilling. The interior of the hydrophone consists of various metals, electronics and elastic bands which are visible through the grilling. The flat extremity of the hydrophone has white / cream coloured text. The bottom extremity of the hydrophone has a circular adapter fitted to connect with the power supply unit. Un hydrophone en forme cylindrique fabriquée principalement en métal avec un corps de couleur noire. La tête de l'hydrophone a un grillage protectif argenté en métal. L'intérieur de l'hydrophone consiste de différents métaux, composantes électroniques et des bandes élastiques qui sont visibles à travers le grillage. L'extrémité plate de l'hydrophone a du texte en couleur blanche / crème. L'extrémité du bas de l'hydrophone a un adapteur circulaire conçu pour se lier avec le bloc d'alimentation.

Decoration

N/A