General Information

Serial #

104

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

SYNTHETIC/ METAL

Dimensions

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

Length

34.7 cm

Width

34.3 cm

Height

N/A

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Space Technology

Category

Miscellaneous

Sub-Category

N/A

Manufacturer

AKA

Unknown

Country

Canada

State/Province

Unknown

City

Unknown

Context

Country

Canada

State/Province

Unknown

Period

1955

Canada

THIS SYSTEM FOR PREDICTING THE NUMBER OF FREQUENCIES WAS DEVELOPED WITHIN THE DEFENSE RESEARCH BOARD FOR USE BY DND PERSONNEL TO IMPROVE RADIO COMMUNICATIONS WITHIN CANADA & TO NATO BASES ABROAD.IT WAS LATER MADE AVAILABLE FOR CIVILIAN USE.

Function

USED TO DETERMINE THE LENGTH OF A RADIO CIRCUIT WHICH WAS THEN USED WITH THE TABLES TO CALCULATE THE MAXIMUM USEABLE FREQUENCY FOR THAT CIRCUIT AS A FUNCTION OF TIME OF DAY, MONTH, & FOR A GIVEN SUNSPOT NUMBER.

Technical

THIS SYSTEM COVERED HIGH LATITUDES WHICH WAS THE CANADIAN REQUIREMENT COMPARED WITH THE AMERICAN SYSTEM WHICH DID NOT PROVIDE COVERAGE OF THE NORTH.THE SYSTEM WAS BASED ON STATISTICAL AVERAGING OF DATA TAKEN BY IONOSPHERES AROUND THE WORLD. THE SYSTEM WAS LATER COMPUTERIZED & USED FOR MANY YEARS.

Area Notes

Unknown

Details

Markings

RED LETTERING READING 'GREAT CIRCLE DISTANCE COMPUTER/ DISTANCE IN KILOMETRES/ FOR USE WITH PREDICTION OPTIMUM TRAFFIC FREQUENCIES FOR NORTHERN LATITUDES', 'Defense Research Telecommunications Establishment/ Radio Physics Laboratory/ Ottawa, Canada', & 'PRODUCED BY THE CANADIAN HYGROGRAPHIC SERVICE 1956', & '5143'/ 'No. 104' STAMPED ON BACK/ RED SCALE PRINTED ON BASE.

Missing

N/A

Finish

WHITE BASE/ TRANSPARENT CIRCLE WITH BLACK LINES, PALE YELLOW LAND MASSES, BLACK LETTERING, & COLOURLESS OCEANS.

Decoration

N/A