From: Peter Davenport <director.nul> Date: Fri, 13 May 2011 06:37:06 -0700 Archived: Fri, 13 May 2011 13:28:57 -0400 Subject: Re: Radar Detection Of UFOs >From: Martin Shough <parcellular.nul> >To: <post.nul> >Date: Thu, 12 May 2011 18:37:21 +0100 >Subject: Re: Radar Detection Of UFOs >>From: Ralph Howard <rhjr.nul> >>To: post.nul >>Date: Thu, 12 May 2011 08:55:27 -0700 (PDT) >>Subject: Radar Detection Of UFOs [was: SETI Summary] >><snip> >>Concerning radar detection, just an FYI for everyone's use... In >>looking into the potential for use of NEXRAD weather radar data >>in UFO sighting investigations, I recently found that there is a >>"scientist and meteorite hobbyist", a Ph.D. fellow at the >>Planetary Science Institute in Tucson AZ, who runs a >>blog/website devoted to providing NEXRAD weather radar data as >>a resource for finding meteorites. Additional quotes from Dr. >>Marc Fries' blog: >>http://radarmeteorites.wordpress.com/ >>"It turns out that Doppler weather radars are a valuable resource >>for not only finding meteorites from fresh falls but also for >>studying the dynamics of the fall itself. In the US, the NEXRAD >>radar network operated by NOAA provides continuous coverage of >>most of the US landmass. Any meteorites that fall here have to >>fall through airspace that is monitored by NEXRAD, and when the >>conditions are right we can spot them on the way down." >Thanks, Ralph, very interesting. I'm surprised that NEXRAD is >thought to have much of a role here, though, because coverage is >so restricted. >The NEXRAD uses a narrow 1-degree pencil beam and a selection of >different scan algorithms to build up coverage in a series of 1- >degree slices at a ponderously slow rate, between about 5 and 10 >_minutes_ depending on mode. This compares with a typical >surveillance radar that fills the same scan volume in as many >_seconds_. (Of course they aren't looking for primary targets >like meteors, but you get the point). The most sensitive (clear >air) NEXRAD mode only covers the sky up about 4 or 5 degrees >elevation anyway, and the less-sensitive precip[itation modes >still only go up to about 19 degrees and take 5 or 6 minutes to >do it. >So I should have thought that even with overlapping coverages the >chances are very small of spotlighting a useful number of >1-degree pieces of meteor trail so as to build up a track - when >a typical trail is gone in seconds . And the wavelength is short >, too - 10cm S-band - not ideal for ionisation returns, which are >favoured at very long wavelengths. ><snip> >>... keeping up with this website makes a lot of >>sense, because of the potential for NEXRAD recording something >>anomalous. >It is intriguing. I want to take a closer look. Thanks for the >tip. >Martin Shough Ralph and Martin, Thank you both for your informed and edifying comments about the NEXRAD radar system. I learned a great deal about that system from what the two of you have written above. The principal shortcoming of that type of "active" radar for detecting short-lived, and high-velocity, targets is as Martin describes... the system might not detect them at all. Therein lies the advantage of using a "passive" radar system, which detects targets in all directions simultaneously, and does so on a virtually continuous basis. An "active" radar radiates a thin "pencil" of electromagnetic radiation, which "sweeps" a target intermittently, which can be defeated easily; a "passive" system radiates in all directions, and does so as long as the signal of choice is being transmitted. For details of such a system, I would recommend a search of the web for the "Naval Space Surveillance System," which uses a 742,000 watt "passive" system, based in Lake Kickapoo, Texas. I believe that the "passive" system I describe in my paper proposes a system that sidesteps the shortcomings of an "active" system, for reasons that Martin correctly identifies in his comments above. I am just leaving for the McMinnville, Oregon, conference, but will respond to any comments, upon my return. Peter NUFORC Listen to 'Strange Days... Indeed' - The PodCast At: http://www.virtuallystrange.net/ufo/sdi/program/ These contents above are copyright of the author and UFO UpDates - Toronto. They may not be reproduced without the express permission of both parties and are intended for educational use only.
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