Military-Grade Awesome

Expand Your Radar Horizons (Part 1)

Upon the conclusion of WWII, the US, and her allies that became NATO, quickly found themselves in an accelerating arms race with the evil superpower nemesis that was the USSR. In the beginning of what became the Cold War, much of the tactics and strategy revolved around expanding the lessons and technology that won the war for the forces of truth, justice, and the American way1. Ballistic missile technology was much in its infancy, as was the atomic bomb. In the interim as these new ideas were being developed, the long-range strategic bomber was the national defense asset of choice.

Building on the lessons learned conducting long range, high altitude campaigns against Japan and Germany, both the US and the Russians began investing heavily in bomber fleets that could reach the other superpower from bases at home. The problem then became knowing that the other guy was coming, so that opposing fleets could be quickly rallied and sent out in response, and so that defense fighters could be scrambled to try and stop the threat. Given the geography of the problem, and the nature of our spherical world, the likely shortest distance attacks would come from the north, and so much effort was made to create and early warning radar picket line, and then quickly expand that line farther and farther as the technologies became available. One such development the increase the capability of the Distant Early Warning (DEW) line was the Texas Towers–large search and height finding radars mounted on oil drilling platforms out along the northeastern Atlantic seaboard.

In the early 1950’s, MIT’s Lincoln Laboratory began studying the feasibility of such radar platforms. They were looking for a way to expand on the capability of the lighter, medium range radars in use on Navy picket ships, currently providing the primary early warning capability. The fact that a great number of American high priority targets were located in the northeastern US, within relatively close striking distance to the Atlantic coastline made the need for better warning capability that much greater. MIT’s analysis was that being able to mount heavy duty, ‘land-based’ type radars out along the continental shelf at a distance of about 100 miles, would expand the radar horizon of the DEW some 300-500 miles, especially when used in conjunction with the picket ships and Airborne Early Warning aircraft.

The Air Defense Command (ADC) supported the Lincoln Lab’s recommendation that 5 towers be built, and MIT was kind enough to provide optimal locations for these towers. In 1952 the ADC pushed the US Air Force to consider the proposal, and after soliciting Judge Advocate guidance as to the legality of permanent military platforms out on the sea, the USAF became convinced of the need to have this capability, and in 1953 the authorized construction to begin. Additionally, the considerations for manning and supporting 24 hour operations began in earnest, with initial estimate of a 22 man crew quickly growing to a 72 man support team. The final count settled out to be around 54 crew–6 officers and 48 airmen, with some of the airmen actually fulfilling jobs that were so maritime specific that the ADC considered turning the operation over to the Navy. The ADC also imposed upon the Air Force a requirement for the towers to be manned by two full crew rotations, so that no one would spend more than one month out on the platform without then being given a full month back onshore.

The radars themselves were sourced from the ground based radars currently in use–the FPS-3A long range search set (later upgraded to FPS-20A) and two FPS-6 long range height finders. Each was enclosed in arctic tower radomes, 55 ft diameter rubberized domes, to protect the radars from the North Atlantic weather. Normal installation for these types of radars involved setting them with a minimum of 150 foot antenna separation, to prevent electronic interference from disrupting the system operation. Since this was not possible on with the platforms size then available, specific layout designs were implemented. The FPS-3A search set was sandwiched between the height finders, and elevated above them. The FPS-6’s were set to point in opposite directions, one facing the land and one the sea, with all three antennas slaved together for synchronized movement.

Ground based radar systems simply tapped into the existing telephone network for communications with the rest of the defense network. Initially, underwater cables were planned to connect each platform to the mainland, but when the cost quickly rose to a projected 2 million dollars per platform, the idea was dropped. Instead multiple channel tropospheric scatter radio was used. The FRC-56 system consisted of three 28 foot diameter parabolic disk antennas, mounted side by side along the platform deck edge. Two at a time were used for message transmission, and all three combined for reception. The signals for this radio were deflected off the tropospheric layer of the atmosphere (between 30-60,000 ft), and worked well over a range of 200 miles, relatively unaffected by atmospheric disturbances. This system was backed up by conventional radios, and the entire operational platform was powered by 250 KW diesel generators. 11 of these generators were onboard, but the system was designed so that less than half would be running at any given time, with the rest in reserve.

In 1954, architecture-engineering firms in New York and Boston were contracted to formulate the design and engineering work for the tower; they were designed to withstand 125 mile per hour winds and 35 foot high waves. There were 5 towers to be built, each know by the designator TT, to be set on the approves sites: Cashes Ledge, TT-1; Georges Shoal, TT-2; Nantucket Shoal, TT-3; Unnamed Shoal, TT-4; and Brown’s Bank, TT-5. The numbering sequence did not reflect the construction priority order, and TT-2 was chosen to be installed first. Built by Bethlehem Steel in Massachusetts, the first platform was completed in spring of 1955. It was an equilateral triangle, measuring 210 feet along the sides, which provided nearly 1/2 acre of deck space.

Tune in next week, and see how the Texas Towers fared during installation and activation!2

Images via texastower.com and wikipedia.org.

 

1. Not everyone is an American, of course, there were also Canadians and such who took a vested interest in many of these endeavors.

2. Don’t cheat and wiki it, you’ll spoil the surprise!

  • The Professor

    Nice article. A lot of effort on both sides was invested in constructing early warning systems in the 50s and 60s, and you couldn't swing a cat in the Arctic regions without hitting a radar installation.
    When you're bored and have some time, take Google Earth and cruise along the Arctic coast of the old USSR (I guess that's mostly Russia now). You can find all sorts of old Soviet radar installations, most of which look abandoned, but not all of them. Duty in those places must have been (and probably still is) absolute hell.

  • CaptianNemo2001

    How many hours did you say you spent cruising the coast of Russia in Google Earth?

    That said, nice article on the TT's. I once read the Wiki (IT BURNS!!) article on the subject. I am firm believer Wikipedia is an index for research. Seen some real shoddy stuff there which is why I do some clean up and original research for it from time to time.

    • skitter

      I worry that I'm enabling citogenesis every time I don't track down two sources for something in an article. And thirded on the excellent series of articles this weekend.

    • The Professor

      Hmph, I waste far too much time farting around with Google Earth. I lose track of time looking at places in Russia, especially Siberia because it's so damned big. It's just an amazing place to go wander around in.

  • Pingback: Expand Your Radar Horizons (Part Duex) : Atomic Toasters()

  • Pingback: Good Use of Government Resources : Atomic Toasters()

-->