Patent US2213874A successfully refreshed from Google Patents.
US2213874A
Expired / Lapsed
US
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Wireless direction finding system
Assignee: International Standard Electric Corp
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Filing: 1938-05-21
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Granted: 1940-09-03
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Expires: 1958-05-21
Abstract
No abstract record available.
Inventors
- 👤 Wagstaffe Charles Freder Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:43
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/14; G01S3/143
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1943-09-03 | 1944-03-04 | 1944-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-09-03 | 1948-03-04 | 1948-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-09-03 | 1952-03-04 | 1952-09-03 | $7700.00 | Window Closed / Lapsed |