General Information

Serial #

1520

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

Wood casing with ebonite and metal elements.

Dimensions

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

Length

31.2 cm

Width

23.3 cm

Height

28.0 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Communications

Category

Radio

Sub-Category

N/A

Manufacturer

AKA

NATIONAL ELECTRIC

Country

United States of America

State/Province

Pennsylvania

City

Pittsburgh

Context

Country

Unknown

State/Province

Unknown

Period

Unknown

Canada

This wavemeter was manufactured by the National Electric Signaling Co. (NESCO), the radio company associated with Canadian physicist and engineer Reginald Fessenden. Born in Bolton East in what is now Quebec in 1866, Fessenden had become by the turn of the 20th century one of the world’s leading researchers in the new and growing field of radio. Working in the United States in the decade between 1900 and 1910, he would be responsible several critical technical advances. The most important of these were his successful demonstration of continuous wave transmission for radio telephony (impossible with the primitive spark gap technology promoted by Marconi) and his patent on the heterodyne principle. Though not fully perfected and commercialized by him, both were revolutionary and remain fundamental to radio technology today.

Function

To measure the frequency of signals emitted by a radio transmitter.

Technical

Because of the need to prevent interference between transmitters, radio operators must determine and adjust the frequency, or wavelength, at which their equipment is operating. The transmission and reception of radio waves depends on the concept of electrical “resonance” described by Oliver Lodge in 1888. In order for a receiver to be sensitive to waves emitted by a transmitter, it must resonate at the same frequency as the transmitter. To be resonant the ratio of inductance and capacitance in the transmitter circuit and the receiver circuit must be the same. This is achieved in a process called tuning. This wavemeter consists of a closed oscillatory circuit with a variable capacitor and a fixed inductance coil. The device features a crystal detector, which, when connected to headphones, allows the wavemeter to act as a “receiver” in order to test a transmitter. Adjusting the capacitor brings the receiving meter into resonance with the transmitter, and by comparing the reading on the capacitor’s scale to a table of calculated values, the frequency of the transmitter can be determined.

Area Notes

Unknown

Details

Markings

Text on the proper top pane: "PHONES/ DETECTOR/ SHORT/ MED/ LONG/ PROTECTIVE/ GAP"/ In recessed letters on the large knob: "CONDENSER"/ Stamped into the wood edge: "SERIAL NO. 1520"

Missing

Lid and leather handle are missing.

Finish

Dark brown finished wood box with a black panel on the top with white text and dark brass-coloured metal.

Decoration

N/A