83:
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.
95:
20:
82:
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
195:. 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.
379:
50:
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
673:
547:
505:
463:
589:
744:
631:
421:
764:
739:
224:
248:
51:
754:
749:
54:-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
191:
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
286:
176:
32:
303:
219:
202:
137:
55:
720:
321:
110:
252:
769:
87:
The array is centered on a ground screen 1,443 feet (439.8 m) in diameter. The arrangement permits accurate
759:
63:
214:
365:
157:
371:
46:
of high priority targets. The worldwide network, known collectively as "Iron Horse", could locate
372:
Extreme close-up hi-res aerial photo of FLR-9 at
Chicksands just before being dismantled in 1996
282:
88:
43:
724:
343:
99:
119:
47:
712:
94:
733:
338:
192:
322:"Former AN/FLR-9 site HFDF in Italy in San Vito dei Normanni, Italy (Google Maps)"
19:
717:
360:
265:
132:
334:
147:
689:
675:
647:
633:
605:
591:
563:
549:
521:
507:
479:
465:
437:
423:
395:
381:
166:
59:
184:
161:
128:
36:
123:
114:
249:"A look inside a classified Cold War-era antenna site, now shut down"
151:
141:
58:
in Alaska was decommissioned. It can be confused with the US Navy's
180:
170:
93:
40:
18:
91:
of signals from up to 4000 nautical miles (7408 km) away.
201:
A decommissioning ceremony for the last active FLR-9, at
198:
Demolition of the FLR-9 at Misawa began in
October 2014.
407:
FLR-9 site at
Ramasun Station, Udon Thani, Thailand
173:, built 1963 to 1965, demolished beginning in 2014.
106:FLR-9s were constructed at the following places:
156:7th Radio Research Field Station/Ramasun Station,
225:List of military electronics of the United States
376:FLR-9 at Ramasun Station, Udon Thani, Thailand
304:"Misawa begins dismantling its 'Elephant Cage'"
16:United States circularly disposed antenna array
670:FLR-9 site at San Vito dei Normanni AS, Italy
242:
240:
701:FLR-9 site at San Vito dei Normanni AS, Italy
8:
144:, USA (formerly designated as Elmendorf AFB)
745:Military radio systems of the United States
544:FLR-9 site at Chicksands, Bedfordshire, UK
575:FLR-9 site at Chicksands, Bedfordshire, UK
281:. New York: Alfred A. Knopf. p. 161.
765:Military electronics of the United States
740:Automatic identification and data capture
62:, which also used a circularly disposed
236:
193:35,000-seat fabric-covered amphitheatre
502:FLR-9 at Misawa, Honshū Island, Japan
460:FLR-9 at Gablingen, Augsburg, Germany
35:, built at eight locations during the
586:FLR-9 site at Clark AFB, Philippines
533:FLR-9 at Misawa, Honshu Island, Japan
491:FLR-9 at Gablingen, Augsburg, Germany
361:AN/FLR-9 Operation and Service manual
266:AN/FLR-9 Operation and Service manual
76:AN/FLR-9 Operation and Service Manual
23:AN/FLR-9 in Elmendorf, Alaska c. 1964
7:
628:FLR-9 site at Karamursel AS, Turkey
617:FLR-9 site at Clark AFB, Philippines
659:FLR-9 site at Karamursel AS, Turkey
339:'Elephant Cage' antennas to be axed
718:FLR-9 photo collection on FTVA.org
14:
177:San Vito dei Normanni Air Station
33:circularly disposed antenna array
302:Slavin, Erik (15 October 2014).
220:High-frequency direction finding
78:describes the array as follows:
713:AN/FLR-9 information on FAS.org
418:FLR-9 at Elmendorf AFB, Alaska
203:Joint Base Elmendorf-Richardson
138:Joint Base Elmendorf-Richardson
56:Joint Base Elmendorf-Richardson
755:Radio-frequency identification
449:FLR-9 at Elmendorf AFB, Alaska
368:– history of the Augsburg site
247:Bowman, Bonney (25 May 2016).
1:
750:Radio frequency antenna types
366:USASA Field Station Augsburg
205:, was held on May 25, 2016.
111:USASA Field Station Augsburg
277:Budiansky, Stephen (2016).
786:
98:AN/FLR-9 antenna array at
396:17.2917333°N 102.868850°E
606:15.204687°N 120.528173°E
522:40.720053°N 141.326580°E
438:61.264486°N 149.851198°W
31:is a type of very large
690:40.645638°N 17.841368°E
648:40.709453°N 29.528074°E
480:48.449278°N 10.863161°E
564:52.042580°N 0.388298°W
443:61.264486; -149.851198
401:17.2917333; 102.868850
347:, 8 October 2012, p. 2
251:. KTVA. Archived from
103:
85:
24:
611:15.204687; 120.528173
527:40.720053; 141.326580
113:(Gablingen Kaserne),
97:
80:
22:
695:40.645638; 17.841368
653:40.709453; 29.528074
569:52.042580; -0.388298
485:48.449278; 10.863161
215:Signals intelligence
685: /
643: /
601: /
559: /
517: /
475: /
433: /
391: /
158:Udon Thani Province
723:2012-03-31 at the
104:
25:
308:Stars and Stripes
89:direction finding
44:direction finding
777:
770:Antennas (radio)
709:
708:
706:
705:
704:
702:
697:
696:
691:
686:
683:
682:
681:
678:
667:
666:
664:
663:
662:
660:
655:
654:
649:
644:
641:
640:
639:
636:
625:
624:
622:
621:
620:
618:
613:
612:
607:
602:
599:
598:
597:
594:
583:
582:
580:
579:
578:
576:
571:
570:
565:
560:
557:
556:
555:
552:
541:
540:
538:
537:
536:
534:
529:
528:
523:
518:
515:
514:
513:
510:
499:
498:
496:
495:
494:
492:
487:
486:
481:
476:
473:
472:
471:
468:
457:
456:
454:
453:
452:
450:
445:
444:
439:
434:
431:
430:
429:
426:
415:
414:
412:
411:
410:
408:
403:
402:
397:
392:
389:
388:
387:
384:
348:
332:
326:
325:
324:. 4 August 2006.
318:
312:
311:
299:
293:
292:
274:
268:
263:
257:
256:
244:
785:
784:
780:
779:
778:
776:
775:
774:
730:
729:
725:Wayback Machine
700:
698:
694:
692:
688:
687:
684:
679:
676:
674:
672:
671:
658:
656:
652:
650:
646:
645:
642:
637:
634:
632:
630:
629:
616:
614:
610:
608:
604:
603:
600:
595:
592:
590:
588:
587:
574:
572:
568:
566:
562:
561:
558:
553:
550:
548:
546:
545:
532:
530:
526:
524:
520:
519:
516:
511:
508:
506:
504:
503:
490:
488:
484:
482:
478:
477:
474:
469:
466:
464:
462:
461:
448:
446:
442:
440:
436:
435:
432:
427:
424:
422:
420:
419:
406:
404:
400:
398:
394:
393:
390:
385:
382:
380:
378:
377:
357:
352:
351:
344:The Japan Times
333:
329:
320:
319:
315:
301:
300:
296:
289:
276:
275:
271:
264:
260:
246:
245:
238:
233:
211:
100:Misawa Air Base
72:
17:
12:
11:
5:
783:
781:
773:
772:
767:
762:
757:
752:
747:
742:
732:
731:
728:
727:
715:
710:
668:
626:
584:
542:
500:
458:
416:
374:
369:
363:
356:
355:External links
353:
350:
349:
327:
313:
294:
287:
269:
258:
255:on 1 May 2017.
235:
234:
232:
229:
228:
227:
222:
217:
210:
207:
189:
188:
174:
164:
154:
145:
135:
126:
117:
71:
68:
15:
13:
10:
9:
6:
4:
3:
2:
782:
771:
768:
766:
763:
761:
758:
756:
753:
751:
748:
746:
743:
741:
738:
737:
735:
726:
722:
719:
716:
714:
711:
707:
669:
665:
627:
623:
585:
581:
543:
539:
501:
497:
459:
455:
417:
413:
375:
373:
370:
367:
364:
362:
359:
358:
354:
346:
345:
340:
336:
331:
328:
323:
317:
314:
309:
305:
298:
295:
290:
288:9780385352666
284:
280:
279:Code Warriors
273:
270:
267:
262:
259:
254:
250:
243:
241:
237:
230:
226:
223:
221:
218:
216:
213:
212:
208:
206:
204:
199:
196:
194:
186:
182:
178:
175:
172:
168:
165:
163:
159:
155:
153:
149:
146:
143:
139:
136:
134:
130:
127:
125:
121:
118:
116:
112:
109:
108:
107:
101:
96:
92:
90:
84:
79:
77:
69:
67:
65:
61:
57:
53:
49:
45:
42:
38:
34:
30:
21:
760:Surveillance
342:
330:
316:
307:
297:
278:
272:
261:
253:the original
200:
197:
190:
105:
86:
81:
75:
73:
28:
26:
693: /
651: /
609: /
596:120°31′41″E
567: /
525: /
512:141°19′36″E
483: /
441: /
428:149°51′04″W
399: /
386:102°52′08″E
133:Philippines
70:Description
734:Categories
699: (
680:17°50′29″E
677:40°38′44″N
657: (
638:29°31′41″E
635:40°42′34″N
615: (
593:15°12′17″N
573: (
551:52°02′33″N
531: (
509:40°43′12″N
489: (
470:10°51′47″E
467:48°26′57″N
447: (
425:61°15′52″N
405: (
383:17°17′30″N
335:Kyodo News
231:References
148:Karamursel
120:Chicksands
554:0°23′18″W
167:Misawa AB
60:AN/FRD-10
721:Archived
209:See also
187:, Italy)
185:Brindisi
162:Thailand
129:Clark AB
37:Cold War
29:AN/FLR-9
124:England
115:Germany
102:c. 1980
66:array.
64:antenna
285:
183:(near
152:Turkey
142:Alaska
181:Italy
171:Japan
41:HF/DF
283:ISBN
74:The
39:for
27:The
341:",
337:, "
52:FLR
736::
306:.
239:^
179:,
169:,
160:,
150:,
140:,
131:,
122:,
48:HF
703:)
661:)
619:)
577:)
535:)
493:)
451:)
409:)
310:.
291:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
