Many thanks to SWLing Post contributor, Andrea Borgnino (IW0HK), who shares the following video–a 15 minute NSA documentary–about the FLR-9 “Elephant Cage” antenna in Anchorage, Alaska.
The SWLing Post
Shortwave listening and everything radio including reviews, broadcasting, ham radio, field operation, DXing, maker kits, travel, emergency gear, events, and more
I lived in Shefford in Bedfordshire, UK, in my childhood, and we all called the Chicksands, FLR-9 antenna the ‘elephant cage’ You can walk very close to the circle now. During the World War II the area around Shefford/Chicksands is able to pick radio signals from around the world, as the Radio signals bounce of the Ionosphere back down to earth in certain places, that where they placed the FLR-9 antenna because of this. The signals in the World War II were intercepted at Chicksands and passed to Bletchley Park for decoding.
I haven’t seen “The Last Elephant Cage” but I was in the USAF stationed at the NATO base in San Vito Dei Normanni, Brindisi, Italy from 1982-1984. It was a shared base both Air Force and Navy. I was a radio maintenance guy but everything we did interfaced with the antenna.
If you’ve been to Florida’s Panhandle west of Tallahassee, you will find nearly identical weather in Brindisi, Italy. Of the different postings I had in the USAF this was my most favorite, 2nd was Eglin AFB, FL near Ft Walton Beach and Niceville. In both places the weather and the people I was there with were both the best ever.
I Was it 202 communications analyst for 16 years in the Air Force was stationed at RAF chick sans three times. The elephant cage was a beautiful so now it’s all done by satellites.
From 82-84, my dad (Capt. Turnage) was stationed at Zweibrücken AFB, and was in charge of managing maintenance on at least one of the elephant cages in use at the time. Thinking you might have run into him at one time or another.
If you have enough time, go to https://www.cia.gov/readingroom/ and search for “krug”. You will find many reports of East Block Elephant Cages. You might try to find them through Google Maps or similar means.
Anyone know what the Soviets have done with theirs, which they called “krug,” (“circle”)? I’m an old USAF guy from the 60s who helped monitor them. They were similar to ours, of course, and were placed at a number of strategic sites around the Soviet Union.
The Imperial Beach (San Diego) FLR, 2007.
http://www.alcue.com/IBFLR-small.jpg
Thanks for posting the pic of the FLR-9 in Imperial Beach.
I saw it many years ago from Hwy5, but forgot to check it out later.
Glad to know I wasn’t “seeing things”.
We used one at RAF Chicksands, UK to monitor Russian aircraft & ground stations in ’66. ??
Does anyone know the type of SDR software that was shown in the video?
There are still two similar arrays in operation in Canada. There’s one in Gander, Newfoundland and another in Masset, British Columbia.
https://goo.gl/maps/am6SgEtFJ9XWr6N46
https://goo.gl/maps/DsSbcMWSWHQbRZm47
Pretty impressive, indeed !
on a “smaller” scale, check out the loop antenna field in switzerland
http://www.coastalradio.org.uk/worldcoastal/bernradio/bern.htm
believe it or not, it’s used for maritime signals… in a country w/o access to sea 🙂 !
I want to take one of these to visit:
https://phys.org/news/2021-02-quantum-entire-radio-frequency-spectrum.html
That is a big installation, but completely useless for civilians: They needed this type of equipment to not miss the direction to very sporadic transmissions. Another usage of such systems than shown in the video was the position finding of foreign submarines.
A submarine gets much more valuable if the other side has no idea where it is. But even submarines have to communicate with their command from time to time. When they had to do it by shortwave, they definitely tried to reduce the duration of their transmissions as far as possible.
The U-Boot swarms of the Nazis coordinated their attacks on allied convoys by single Morse code letters. On the long run it did not help them as the allies developed a direction finding system with two loop antennas at a 90° angle and a display on an oscilloscope.
As a civilian you use turnable antennas like yagis or receiving antennas like Beverages. Your primary concern is to suppress any signals from other directions so you can dig out what interests you.
I am sure the US today have satellite systems working like the the worldwide Kiwi SDR system: With knowing the exact location of the receiving station and having a very exact time base, you measure the relative transmission delays and derive the position of the transmitter from this information.
The last elephant cage is in Alaska not by chance: The shortwave propagation near the magnetic poles is very erratic. Perhaps most satellites that do this job today do not fly so far to the north or south: For quite some time they would fly over areas that are of hardly any interest.
Submarines all use VLF from 5 kHz to 50 kHz or so. It’s been a VERY long time since they had any HF on board.
Funny story. I was in San Diego on a job in 1980 and went down to Imperial Beach to take a look at the FLR-9 there. Weirdly you could get pretty close to it by walking along the beach. Once I got back to my hotel I looked in the phonebook and found the number for the Naval Radio Receiving Facility (NRRF) which was the listening post. I called the number and started to ask a question about the array. Before I could say much the guy on the other side of the line asked me how did I get that phone number. I said that it was in the phonebook and then quickly hung up.
I work in Italy where we had one at the San Vito Air Station.
I was born in Brindisi (about 10 km from that base) and I remember I used to go on top of my block of flat to look at the antenna array in San Vito dei Normanni. You could see the elephant cage from far away. It was really big.
I remember it. I used to look at it as a child from 10k away.
https://www.forgottenairfields.com/airfield-brindisi-san-vito-dei-normanni-586.html
Would there be another radio/RADAR system that used a similar antenna? There are two pronounced open circles at two former SAC bases in northern Michigan (Kinross, KI Sawyer) West of the runaway (Sawyer) and east (Kinross). These locations are not listed as FLR sites. Would there be another radio/RADAR system that used an open field antenna system? I’m curious how theses areas remain clear long after decommissioning. Thanks for any insight!
I think that those were for parachute landing practice.
My hay field is not quite big enough. I’m gonna need another 30 acres…
Here another look
https://web.archive.org/web/20170501061010/http://www.ktva.com/inside-a-classified-cold-war-era-antenna-site-now-shut-down-625/
Was stationed in Karamursel Turkey and Wakannai Japan 1966-1969. Morse code eavesdropping on adversaries communications. Amazing electronic intercept array back then
Lets make a swling.com survey: Who won’t like that cage in his back yard?
I was just trying to decide how many trees I would need to clear! 🙂
We could string a wire version right across the valley 🙂
Let’s get started!
I had one very close to my back yard, about 8 miles actually. There was one located Naval Security Group, Northwest in Chesapeake, VA. The state line runs through the property on which it was located.
We still have one near Augsburg.