US3798647A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High frequency passive radio range finder
Assignee: United States Department of the Navy
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Filing: 1972-05-25
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Granted: 1974-03-19
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Expires: 1992-05-25
Abstract
Abstract The application discloses an invention for determining the direction and distance of a remotely located radio source based on the principle that the distance to a station is inversely proportional to the root mean square value or peak value of the received continuous bearing signal as a function of time which has first been passed through a twenty minute averaging or smoothing window.
Inventors
- 👤 A Bailey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:40
CPC Classifications
G; G01; G01S; G01S11/00; G01S11/02; G01S11/06
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
116 words
An improved passive type high frequency radio range finder comprising: a. A low pass filter having a pass band capable of receiving radio signals in the 3 to 30 mega hertz range that fluctuate about a 20 minute period; b. A root mean square or peak reading digital voltmeter coupled to said filter, to measure the strength 3 to to mega hertz signal over said period; c. Means coupled to said voltmeter for determining the root mean square or peak deviation, and; d. Means including a criteria testing device whereby a most probable range to a radio trasmitter estimate is obtained by comparing invErsely either the root mean square or peak deviation to the range chart.
Claim 2
Dependent Claim
116 words
An improved passive type high frequency radio range finder comprising: a. A low pass filter having a pass band capable of receiving radio signals in the 3 to 30 mega hertz range that fluctuate about a 20 minute period; b. A root mean square or peak reading digital voltmeter coupled to said filter, to measure the strength 3 to to mega hertz signal over said period; c. Means coupled to said voltmeter for determining the root mean square or peak deviation, and; d. Means including a criteria testing device whereby a most probable range to a radio trasmitter estimate is obtained by comparing invErsely either the root mean square or peak deviation to the range chart.
Claim 3
Dependent Claim
31 words
The improved passive type high frequency radio direction finder of claim 1 wherein the input to said filter is coupled to the radio frequency output of conventional radio direction finding equipment.
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) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |