Patent US3977004A successfully refreshed from Google Patents.
US3977004A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aircraft VLF/LF/MF window antenna receiving system
Assignee: United States Department of the Navy
•
Filing: 1975-06-16
•
Granted: 1976-08-24
•
Expires: 1995-06-16
Abstract
Abstract Apparatus for receiving the horizontal and vertical electric field compons of incoming VLF, LF, and MF (10 KHz to 3000 kHz) signals that is easily portable and installed within minutes aboard aircraft with windows. A sheet of metal or matrix of interconnecting wires is placed against the inside surface of non-conducting windows on each side of the aircraft fuselage and used as the receiving antennas. The voltage sum of the two window antennas is proportional to the vertical electric field. The voltage difference of the two window antennas is proportional to the horizontal electric field particularly when the antennas are forward or to the rear of the wings extending from the fuselage.
Inventors
- 👤 John E. Bickel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:46
CPC Classifications
H; H01; H01Q; H01Q1/00; H01Q1/12; H01Q1/1271; H01Q1/27; H01Q1/28; H01Q9/00; H01Q9/04; H01Q9/30; H01Q9/40
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
107 words
An antenna receiving system for detecting VLF/LF electric field variation aboard in flight aircraft comprising: first and second antenna means each being adapted for quick and easy mounting on the surface of an aircraft window; signal combiner means connected to said first and second antenna means for selectively providing the sum and the difference of the signal outputs from said first and second antenna means, said first and second antenna means being symmetrically oriented such that said sum and said difference of the signal outputs are proportional, respectively, to the vertical and horizontal electric fields associated with the signals received by said first and second antenna means.
Claim 2
Dependent Claim
107 words
An antenna receiving system for detecting VLF/LF electric field variation aboard in flight aircraft comprising: first and second antenna means each being adapted for quick and easy mounting on the surface of an aircraft window; signal combiner means connected to said first and second antenna means for selectively providing the sum and the difference of the signal outputs from said first and second antenna means, said first and second antenna means being symmetrically oriented such that said sum and said difference of the signal outputs are proportional, respectively, to the vertical and horizontal electric fields associated with the signals received by said first and second antenna means.
Claim 3
Dependent Claim
18 words
The system of claim 1 wherein said first and second antenna means each comprise a wire mesh antenna.
Claim 4
Dependent Claim
95 words
The system of claim 1 wherein said signal combiner means comprises: first and second transformers each having an output winding; switch means connected to said first and second transformer output windings and being actuable between first and second positions; whereby the voltage from said first transformer output winding is added to the voltage from said second transformer output winding when said switch means is in said first position and the voltage from said first transformer output winding is subtracted from the voltage from said second transformer winding when said switch is in said second position.
Claim 5
Dependent Claim
26 words
The system of claim 3 further including means connected to said signal combiner means for measuring and recording the voltage output of said signal combiner means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |