Readers Comment: Radar Beeps |
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Oops, I forgot to post the piece after posting back in September the "Radar Adds Beep to Home Sets" article from the February 28, 1964 issue of Electronics magazine. The April 20th issue published a reader response to the problem of the U.S. Air Force recently commissioned AN/FPS-24 long range "superpower radar" in some of the country's major seaboard and northern cities. Designed to watch for ICBM's and intruding long-range aircraft from the U.S.S.R., it operated in the 214 to 236 MHz band (VHF) at a 7.5 megawatt peak power output. Immediately there were massive reports from surrounding homeowners and businesses about the annoying beeps being heard on radio and television every time the rotating antenna pointed in their direction (12 second rotation period). The anonymous reader evidently had access to the installations and claimed the equipment was 1940s technology and wholly inadequate for modern needs. Its operational band was chosen because that is what the technology would support, and that modern systems with modern components could do the job better using microwave frequencies (i.e., S-band). Basically, he was accusing the project of being a DoD / contractor sweetheart deal. Readers Comment: Radar Beeps
The question of basic policy implied by the Air Force use of superpower radar near large cities may be just as horrendous as those raised by you concerning DOD on page 5 of the same issue - and, indeed, are very closely related. The rumors in Pittsburgh differ from your newsletter. The Federal Communications Commission at Buffalo is said to be much concerned about the Air Force radar interference and is not inclined to class 100 megawatts blanketing a city as equivalent to a ham radio next door. But where the military is in control what can they do? There is nothing secret about the radar parameters. The beam shape can be estimated from the time-duration of the beep and by inspecting the dish and feed from a couple of miles. But why bother - anyone can drive to within 300 feet of the open antenna. From a couple of miles at a suitable elevation one can estimate the power and wavelength with Lecher wires. The max range one gets by matching the beep with the living-room piano, and the pulse width is visible on the family tv by expanding the horizontal sweep. There are a lot of questions that an engineer would want to ask. Why are they using this long wavelength which is extremely difficult to shield against (as compared to microwaves) and which went out of radar use at the beginning of World War II? Probable answers: to reduce rain response, to avoid radial blind speeds, and to obtain high coherent power for moving target indication. But these are lazy reasons. There must be many other ways of solving these engineering problems. Why locate these sets next to big cities? Ostensibly, to control Nike missiles without video relaying. Probable real reason: this military net is being sold as a civilian air-traffic control system! ! When you take a close look at the military arguments, the future civilian use will be given as an excuse. But when you point out that this method of traffic control was obsolescent at the end of World War II, you will be told of the military need. The evident hope of the military is to get so much money tied up that it will be too late to blow the whistle. Do we really have to pay this kind of price for protection against sub-sonic bombers? It is one thing to jazz up the economy and allay the neurotic anxiety of the populace by building up a Maginot line named Distant Early Warning. It is something else to use taxpayers money to tie up the technological future of this country in little knots. I could be wrong, but my guess is that these decisions were made by military and civilian bureaucrats whose technological learning stopped at the end of World War II and who have been busy building a personal empire ever since. One reason why I think so: I visited the Pittsburgh radar set-up. Everything I saw was World War II vintage. This is a new installation costing over $20 million. Rooms filled with racks of smoking-hot vacuum tubes! Video displays that were inadequate for heavy traffic when designed at Massachusetts Institute of Technology in 1944. If a computer manufacturer tried to sell this stuff, he would be laughed into bankruptcy... Why is the Air Force getting away with this in Pittsburgh? The answer: Pittsburgh is a hilly town and less than five percent of the population is being hit - a feature well known in the siting of long-wave radar. I predict that when they set up such a search radar near a flat city so that 50 percent of the people are annoyed, the military will be hoist on their own petard - at the taxpayer's expense ... (Name Withheld) • More recently, Name Withheld told us that the situation is much worse than the fact that the Russians have 800 low-speed bombers; he believes it involves the "nth country problem." Right now, n equals four, because four countries possess atomic weapons capabilities. In the future, "some small nth country might hijack an ordinary commercial airliner and drop an atomic bomb where it pleases." The military would then have to be able to protect against "a devil of a problem," by identifying the airliner in a hurry and shooting it down. In this situation, our reader adds, Nike missile sites near cities do make sense.
Posted March 28, 2019 |
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