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In article , richard.p.henry@saic
mentioned... "Tom Sevart" wrote in message ... "WB3FUP (Mike Hall)" wrote in message ... 10KV to fire magnetron in counter battery radar. Took six marines to stop me from burying my screw driver in the chest of the asshole that thought it would be cute to push the radiate button. I remember hearing the story of an Air Force tech working on a 30' radar dish. For some dumb reason, someone energized it and promptly microwaved him to death. Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... A Raytheon corporate legend is that one of the engineers discovered the microwave oven principle when a radar melted a chocolate bar in his shirt pocket. When I was in the army at Ft. Monmouth, NJ, we trained on a radar trainer, had a klystron that put out 1W to the horn on the top of the unit. We could put our finger over the horn and feel it get mildly warm from the RF. Big deal. The Real Thing put our 5 megawatts! -- @@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@ h@e@r@e@@ ###Got a Question about ELECTRONICS? Check HERE First:### http://users.pandora.be/educypedia/e...s/databank.htm My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 at hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half). http://www.everybookstore.com You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it: http://physics.nist.gov/cuu/Units/binary.html @@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@ u@e@n@t@@ |
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Watson A.Name - 'Watt Sun' wrote in message ...
In article , richard.p.henry@saic mentioned... "Tom Sevart" wrote in message ... "WB3FUP (Mike Hall)" wrote in message ... 10KV to fire magnetron in counter battery radar. Took six marines to stop me from burying my screw driver in the chest of the asshole that thought it would be cute to push the radiate button. I remember hearing the story of an Air Force tech working on a 30' radar dish. For some dumb reason, someone energized it and promptly microwaved him to death. Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... A Raytheon corporate legend is that one of the engineers discovered the microwave oven principle when a radar melted a chocolate bar in his shirt pocket. When I was in the army at Ft. Monmouth, NJ, we trained on a radar trainer, had a klystron that put out 1W to the horn on the top of the unit. We could put our finger over the horn and feel it get mildly warm from the RF. Big deal. The Real Thing put our 5 megawatts! -- Sure, but the pulse width is only a microsecond, so the average power is only 5 watts at one pulse per second. I forget the rep rate of the one I woked on but at 6uS per mile and 400 miles round trip, the rep rate would be about 400 Hz. So it's 400 times 5, or 2KW. -Bill |
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(Avery Fineman) wrote in message ...
In article , (Bill Bowden) writes: Watson A.Name - 'Watt Sun' wrote in message ... In article , richard.p.henry@saic mentioned... "Tom Sevart" wrote in message ... "WB3FUP (Mike Hall)" wrote in message ... 10KV to fire magnetron in counter battery radar. Took six marines to stop me from burying my screw driver in the chest of the asshole that thought it would be cute to push the radiate button. I remember hearing the story of an Air Force tech working on a 30' radar dish. For some dumb reason, someone energized it and promptly microwaved him to death. Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... A Raytheon corporate legend is that one of the engineers discovered the microwave oven principle when a radar melted a chocolate bar in his shirt pocket. When I was in the army at Ft. Monmouth, NJ, we trained on a radar trainer, had a klystron that put out 1W to the horn on the top of the unit. We could put our finger over the horn and feel it get mildly warm from the RF. Big deal. The Real Thing put our 5 megawatts! Sure, but the pulse width is only a microsecond, so the average power is only 5 watts at one pulse per second. I forget the rep rate of the one I woked on but at 6uS per mile and 400 miles round trip, the rep rate would be about 400 Hz. So it's 400 times 5, or 2KW. -Bill A very rough estimate of "radar range" (time out to return of echo) is 500 feet per microsecond. For a 200 mile search radar the time out to echo return is 2+ milliseconds, depending on whether it is calibrated for statute or nautical miles. Typical PRF for those 200 mile search radars was 400 Hz (PRT of about 2.5 mSec). Average power output is Peak x ((pulse width)/(repetition time)) or 5 MW divided by 2500 = 2 KW. 2 KW concentrated in a 2 to 5 degree cone can have a devastating heating effect on human tissue. One may or may not be "in" the cone of the beam right up close to the feedhorn but, with the construction of most search radars (maritime or ground) there isn't much walk-around space to get away from the feedhorn or the very close in-person effects of microwave radiation. When working on HIGH POWER RF at any frequency, believe in the inverse square law and put as much distance from the antenna as possible...or have a trusted person down on the power controls who keeps the thing OFF while up there doing whatever. I think it would be an interesting subject to compare peak power RF effects versus average power RF effects. I can't seem to find much on that in hundreds of pages of medical-biological reports on the effects of RF radiation on human tissue. Unfortunately, that has been pretty well shunted aside so that someone can get their pet "alternate universe" speculations going on in here. :-) All this gee-whizzy speculation stuff leaves me shocked. But not fatally so... Len Anderson retired (from regular hours) electronic engineer person There are a few refs and calculations in http://arXiv.org/pdf/physics/0102007 Lu, et al (referenced) found that peak power was responsible for spark-gap transmitter injury in rats. Microwave hearing (referenced somewhat; see a review Supplement to Radio Science in 1977) also seems to be because of peak, not average, power. John John Michael Williams |
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Watson A.Name - 'Watt Sun' wrote in message ...
In article , richard.p.henry@saic mentioned... "Tom Sevart" wrote in message ... "WB3FUP (Mike Hall)" wrote in message ... 10KV to fire magnetron in counter battery radar. Took six marines to stop me from burying my screw driver in the chest of the asshole that thought it would be cute to push the radiate button. I remember hearing the story of an Air Force tech working on a 30' radar dish. For some dumb reason, someone energized it and promptly microwaved him to death. Some of these stories are hair rasing... and I'm too much of a weenie to stick my tongue on a 9V battery... A Raytheon corporate legend is that one of the engineers discovered the microwave oven principle when a radar melted a chocolate bar in his shirt pocket. When I was in the army at Ft. Monmouth, NJ, we trained on a radar trainer, had a klystron that put out 1W to the horn on the top of the unit. We could put our finger over the horn and feel it get mildly warm from the RF. Big deal. The Real Thing put our 5 megawatts! -- Sure, but the pulse width is only a microsecond, so the average power is only 5 watts at one pulse per second. I forget the rep rate of the one I woked on but at 6uS per mile and 400 miles round trip, the rep rate would be about 400 Hz. So it's 400 times 5, or 2KW. -Bill |
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