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center ring covers the 6 to 18-MHz range (band B) and the inner ring covers the 18 to 30-MHz range (band C). Band A contains 48 sleeve monopole elements spaced 78.4 feet (23.9 m) apart (7.5 degrees). Band B contains 96 sleeve monopole elements spaced 37.5 feet (11.43 m) apart (3.75 degrees). Band C contains 48 antenna elements mounted on wooden structures placed in a circle around the central building. Bands A and B elements are vertically polarized. Band C elements consist of two horizontally polarized dipole antenna subelements electrically tied together, and positioned one above the other.
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The antenna array is composed of three concentric rings of antenna elements. Each ring of elements receives RF signals for an assigned portion of the 1.5 to 30-MHz radio spectrum. The outer ring normally covers the 2 to 6-MHz range (band A), but also provides reduced coverage down to 1.5 MHz. The
206:. In early May 2002, systematic dismantling of the FLR-9 at San Vito began, and it was totally deconstructed by the end of that month. Although the markings of where the array stood remain in the ground, the structure is completely gone.
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communications almost anywhere on Earth. Because of the exceptionally large size of its outer reflecting screen (1056 vertical steel wires supported by 96 120-foot (37 m) towers), the
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65:-9 was commonly referred to by the nickname "Elephant Cage." Constructed in the early to mid 1960s, in May 2016 the last operational FLR-9 at
202:
Advances in technology have made the FLR-9 obsolete. In 1997, the FLR-9 at the former Clark AB in the
Philippines was converted into a
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The array is centered on a ground screen 1,443 feet (439.8 m) in diameter. The arrangement permits accurate
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of high priority targets. The worldwide network, known collectively as "Iron Horse", could locate
383:
Extreme close-up hi-res aerial photo of FLR-9 at
Chicksands just before being dismantled in 1996
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333:"Former AN/FLR-9 site HFDF in Italy in San Vito dei Normanni, Italy (Google Maps)"
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260:"A look inside a classified Cold War-era antenna site, now shut down"
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in Alaska was decommissioned. It can be confused with the US Navy's
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of signals from up to 4000 nautical miles (7408 km) away.
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A decommissioning ceremony for the last active FLR-9, at
209:
Demolition of the FLR-9 at Misawa began in
October 2014.
418:
FLR-9 site at
Ramasun Station, Udon Thani, Thailand
184:, built 1963 to 1965, demolished beginning in 2014.
117:FLR-9s were constructed at the following places:
167:7th Radio Research Field Station/Ramasun Station,
236:List of military electronics of the United States
387:FLR-9 at Ramasun Station, Udon Thani, Thailand
315:"Misawa begins dismantling its 'Elephant Cage'"
27:United States circularly disposed antenna array
681:FLR-9 site at San Vito dei Normanni AS, Italy
253:
251:
712:FLR-9 site at San Vito dei Normanni AS, Italy
8:
155:, USA (formerly designated as Elmendorf AFB)
756:Military radio systems of the United States
555:FLR-9 site at Chicksands, Bedfordshire, UK
586:FLR-9 site at Chicksands, Bedfordshire, UK
292:. New York: Alfred A. Knopf. p. 161.
776:Military electronics of the United States
751:Automatic identification and data capture
73:, which also used a circularly disposed
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204:35,000-seat fabric-covered amphitheatre
513:FLR-9 at Misawa, Honshū Island, Japan
471:FLR-9 at Gablingen, Augsburg, Germany
46:, built at eight locations during the
597:FLR-9 site at Clark AFB, Philippines
544:FLR-9 at Misawa, Honshu Island, Japan
502:FLR-9 at Gablingen, Augsburg, Germany
372:AN/FLR-9 Operation and Service manual
277:AN/FLR-9 Operation and Service manual
87:AN/FLR-9 Operation and Service Manual
34:AN/FLR-9 in Elmendorf, Alaska c. 1964
7:
639:FLR-9 site at Karamursel AS, Turkey
628:FLR-9 site at Clark AFB, Philippines
670:FLR-9 site at Karamursel AS, Turkey
350:'Elephant Cage' antennas to be axed
729:FLR-9 photo collection on FTVA.org
25:
188:San Vito dei Normanni Air Station
44:circularly disposed antenna array
313:Slavin, Erik (15 October 2014).
231:High-frequency direction finding
89:describes the array as follows:
724:AN/FLR-9 information on FAS.org
429:FLR-9 at Elmendorf AFB, Alaska
214:Joint Base Elmendorf-Richardson
149:Joint Base Elmendorf-Richardson
67:Joint Base Elmendorf-Richardson
766:Radio-frequency identification
460:FLR-9 at Elmendorf AFB, Alaska
379:– history of the Augsburg site
258:Bowman, Bonney (25 May 2016).
1:
761:Radio frequency antenna types
377:USASA Field Station Augsburg
216:, was held on May 25, 2016.
122:USASA Field Station Augsburg
288:Budiansky, Stephen (2016).
797:
109:AN/FLR-9 antenna array at
407:17.2917333°N 102.868850°E
617:15.204687°N 120.528173°E
533:40.720053°N 141.326580°E
449:61.264486°N 149.851198°W
42:is a type of very large
701:40.645638°N 17.841368°E
659:40.709453°N 29.528074°E
491:48.449278°N 10.863161°E
575:52.042580°N 0.388298°W
454:61.264486; -149.851198
412:17.2917333; 102.868850
358:, 8 October 2012, p. 2
262:. KTVA. Archived from
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622:15.204687; 120.528173
538:40.720053; 141.326580
124:(Gablingen Kaserne),
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33:
706:40.645638; 17.841368
664:40.709453; 29.528074
580:52.042580; -0.388298
496:48.449278; 10.863161
226:Signals intelligence
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612: /
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528: /
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169:Udon Thani Province
734:2012-03-31 at the
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319:Stars and Stripes
100:direction finding
55:direction finding
16:(Redirected from
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335:. 4 August 2006.
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736:Wayback Machine
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366:External links
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266:on 1 May 2017.
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299:9780385352666
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290:Code Warriors
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771:Surveillance
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264:the original
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704: /
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607:120°31′41″E
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523:141°19′36″E
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439:149°51′04″W
410: /
397:102°52′08″E
144:Philippines
81:Description
745:Categories
710: (
691:17°50′29″E
688:40°38′44″N
668: (
649:29°31′41″E
646:40°42′34″N
626: (
604:15°12′17″N
584: (
562:52°02′33″N
542: (
520:40°43′12″N
500: (
481:10°51′47″E
478:48°26′57″N
458: (
436:61°15′52″N
416: (
394:17°17′30″N
346:Kyodo News
242:References
159:Karamursel
131:Chicksands
565:0°23′18″W
178:Misawa AB
71:AN/FRD-10
732:Archived
220:See also
198:, Italy)
196:Brindisi
173:Thailand
140:Clark AB
48:Cold War
40:AN/FLR-9
135:England
126:Germany
113:c. 1980
77:array.
75:antenna
296:
194:(near
163:Turkey
153:Alaska
192:Italy
182:Japan
52:HF/DF
18:FLR-9
294:ISBN
85:The
50:for
38:The
352:",
348:, "
63:FLR
747::
317:.
250:^
190:,
180:,
171:,
161:,
151:,
142:,
133:,
59:HF
714:)
672:)
630:)
588:)
546:)
504:)
462:)
420:)
321:.
302:.
20:)
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