VLF AND ELF SPECTROMETER

• US 3,638,112 A
• Filed: 07/26/1963
• Issued: 01/25/1972
• Est. Priority Date: 07/26/1963
• Status: Expired due to Term

• Current Assignee: David D. Woodbridge, James A. Lasater
• Original Assignee: David D. Woodbridge, James A. Lasater
• Inventors: Lasater, James A., Woodbridge, David D.
• Primary Examiner(s): Farley, Richard A.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US04/297,803
• Time in Patent Office: 3,105 Days
• Field of Search: 343/787,788,199,113 324/34,43,47,8,7,77B 73/170 334/78-84,4
• US Class Current: 324/76.19
• CPC Class Codes: G01R 23/00 Arrangements for measuring frequencies; Arrangements for analysing frequency spectra

Abstract

Apparatus for detecting and recording an electromagnetic radiation spectrum in the VLF and ELF range including a ferromagnetic cored antenna in a variably tuned circuit, a drive motor for sweeping the tuning and actuating a sweep marker, a time reference, and a voice and data amplifier. The output signals of these devices are fed into a multichannel recorder. A plurality of such variably tuned circuits may be used.

Claims

1. An antenna for VLF and ELF electromagnetic waves comprising:

a first multiplicity of ferromagnetic rod sections parallel to each other and having equal overall lengths, a second multiplicity of ferromagnetic rods of equal overall lengths which are shorter than the lengths of the first multiplicity of rod sections, said second multiplicity of rods surrounding said first multiplicity of rod sections, a coil of wire wound around said multiplicities of rods, and a mounting means for supporting said rods and coil.

2. An antenna for extra low frequency and very low frequency electromagnetic waves comprising:

a first multiplicity of hOllow ferromagnetic rod sections parallel to each other and having equal overall lengths, a second multiplicity of hollow ferromagnetic rods of equal overall lengths which are shorter than the lengths of the first multiplicity of rod sections, said second multiplicity of rods surrounding said first multiplicity of rod sections, a coil of wire wound around said multiplicities of rods, and a mounting means for supporting said rods and coil.

3. A radiation spectrometer comprising:

an antenna, a tuner connected to said antenna to form a high Q tuned circuit whose resonance frequency is capable of being varied through a selected range of frequencies below 30 kilocycles, a drive means for sweeping said variable tuned circuit through said range of frequencies connected to said tuner, an amplifier connected to said antenna, a recorder connected to said amplifier, and a means for producing a signal actuated by said drive means and connected to said recorder.

4. In combination with the spectrometer specified in claim 3, a timing receiver connected to said recorder.

5. In combination with the spectrometer specified in claim 3, a data-receiving means connected to said recorder.

6. A radiation spectrometer comprising:

a plurality of antennas, a tuner connected to each said antenna to form a plurality of high Q tuned circuits whose respective resonance frequencies are capable of being varied through selected ranges of frequencies below 30 kilocycles, a drive means for sweeping said variable tuned circuits through said respective ranges of frequencies connected to said tuners, an amplifier connected to each said antenna, a recording means connected to each said amplifier, and a means for producing a signal actuated by said drive means and connected to said recording means.

7. A spectrometer as specified in claim 6, wherein the recording means is a single recorder which simultaneously records signals received from said amplifiers and said signal-producing means.

8. A radiation spectrometer comprising:

a ferromagnetic core, a wire coil wound around said core, a variable condenser connected across said coil, a drive means for sweeping said variable condenser through a selected range of capacitance values connected to said condenser, an amplifier connected to said coil and condenser, a recorder connected to said amplifier, and a means for producing a signal actuated by said drive means and connected to said recorder.

9. A radiation spectrometer comprising:

a plurality of ferromagnetic cores, a wire coil wound around each said core, a variable condenser connected across each said coil, a drive means for sweeping said variable condensers through respective selected ranges of capacitance values connected to the condenser, an amplifier connected to each connected coil and condenser, a recording means connected to said amplifiers, and a means for producing a signal actuated by said drive means and connected to said recording means.