Bob -
I apoligize for the tardinesss of reply to your query. December is a busy time for me with projects finishing and planning for 2011 projects. I would suggest the University of Alaska's work with Red Sprites and Blue Jets. http://elf.gi.alaska.edu/ What are Red Sprites and Blue Jets? Red sprites and blue jets are upper atmospheric optical phenomena associated with thunderstorms that have only recently been documented using low light level television technology. The first images of a sprite were accidently obtained in 1989 (Franz et al. , 1990). Beginning in 1990, about twenty images have been obtained from the space shuttle (Vaughan et al. , 1992; Boeck et al. , 1994). Since then, video sequences of well over a thousand sprites have been captured. These include measurements from the ground ( Lyons, 1994; Winckler, 1995) and from aircraft (Sentman and Wescott, 1993; Sentman et al. , 1995 ). Numerous images have also been obtained from aircraft of blue jets ( Wescott et al. , 1995 ), also a previously unrecorded form of optical activity above thunderstorms. Blue jets appear to emerge directly from the tops of clouds and shoot upward in narrow cones through the stratosphere. Their upward speed has been measured to be about 100 km per second. Anecdotal reports of "rocket-like" and other optical emissions above thunderstorms go back more than a century (Lyons, 1994), and there have been several pilot reports of similar phenomena (Vaughan and Vonnegut, 1989). Possibly associated gamma ray bursts and TIPPS have also recently reported. Together, these phenomena suggest that thunderstorms exert a much greater influence on the middle and upper atmospheres than was previously suspected. ==== Specific to your VLF capabilities on this satellite ...... Look at the 1997 PhD disseration by Steve Cummer submitted to the Department of Electrical Engineering at Stanford University: Lightning and Ionospheric Remote Sensing Using VLF/ELF Radio Atmospherics http://www-star.stanford.edu/~vlf/publications/theses/cummerthesis.pdf at Stanford University: Lightning and Ionospheric Remote Sensing Using VLF/ELF Radio Atmospherics http://www-star.stanford.edu/~vlf/publications/theses/cummerthesis.pdf This research was supported by the Office of Naval Research through grants N00014-93-1-1201 and N00014-95-1-1095, by the Air Force Office of Scientific Research through grant F49620-97-1-0468, and by the Air Force Phillips Laboratory through grant F19628-96-C-0149. ==== That should get you started Bob. Greg w9gb ------------------------------ Message: 16 Date: Sat, 11 Dec 2010 14:13:33 -0500 (EST) From: "Bob Bruninga " <bruni...@usna.edu> Subject: [amsat-bb] LF Satellite ideas? To: amsat-bb@amsat.org Message-ID: <20101211141333.agv57...@msan1.usna.edu> Content-Type: text/plain; charset=us-ascii Is 137 KHz possible from space? Our next Cubesat will have a 1100 meter long antenna (think tether satellite). It will ultimatelly be an electrodynamic tether but the first one will have NO ACTIVE ELECTRONICS connected to the tether. So I have asked them to make it 1100m long instead of a generic 1km tether to try to make it resonant in an amateur band. THe path loss at 137 KHz is 60 dB LESS than it is at 2 meters, so it shouldn't take much to communicate with an 1100m long antenna. I'm sorry I didnt think of this sooner, but I need a real SCIENCE justification for this. Maybe LF that low will never punch through the ionosphere, or maybe it will be completely absorbed. Can give good science on this idea? Bob, WB4APR ------------------------------ Message: 16 Date: Sat, 11 Dec 2010 14:13:33 -0500 (EST) From: "Bob Bruninga " <bruni...@usna.edu> Subject: [amsat-bb] LF Satellite ideas? To: amsat-bb@amsat.org Message-ID: <20101211141333.agv57...@msan1.usna.edu> Content-Type: text/plain; charset=us-ascii Is 137 KHz possible from space? Our next Cubesat will have a 1100 meter long antenna (think tether satellite). It will ultimatelly be an electrodynamic tether but the first one will have NO ACTIVE ELECTRONICS connected to the tether. So I have asked them to make it 1100m long instead of a generic 1km tether to try to make it resonant in an amateur band. THe path loss at 137 KHz is 60 dB LESS than it is at 2 meters, so it shouldn't take much to communicate with an 1100m long antenna. I'm sorry I didnt think of this sooner, but I need a real SCIENCE justification for this. Maybe LF that low will never punch through the ionosphere, or maybe it will be completely absorbed. Can give good science on this idea? Bob, WB4APR _______________________________________________ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
