Drats. Bad news.. Good news!
Bad news: I was thinking that maybe 137KHz would leak through the ionosphere straight up, but then just realized that this is a tether satellite, so the antenna is VERTICAL! Thus, a null straight down.
So maybe the only application then is to use it as a receive antenna and LISTEN to the aliens (galactic noise on 137 Khz).
But still with a path loss that is a million times less than on 2 meters, it would seem that something terrestrial could be easily heard.
GOOD NEWS? Woaha? How about this. Use the 1.1km vertical long wire as a 10 wavelength end fed on the 160m band and the lobes point more downward!? The gain there would about 10 dB and the path loss is still 40 dB better than on 2m.
So if we can hear a 1W amsat on 2m, then we should be able to hear a 1 milliwatt transmitter on 160m with 20 dB stronger signal! (Of course noise level can easily be 20 dB stronger?)
I really don't know enough about 160m to go further. Gotta start reading...
Bob, WB4APR
---- Original message ----
Date: Sun, 12 Dec 2010 08:52:26 +0000 (GMT) From: [email protected] (on behalf of GRAHAM SHIRVILLE [email protected]) Subject: [amsat-bb] Re: LF Satellite ideas? To: [email protected],John Magliacane [email protected]
Hi Bob, If the ionosphere screens all the terrestrial signals at that height then maybe your 136kHz RX could be used to listen to radiation received from outer space at that frequency which normally we cannot listen to on earth. Sound like fundamental research to me but maybe it has already been done and redone. 73 GrahamG3VZV
--- On Sun, 12/12/10, John Magliacane [email protected] wrote:
From: John Magliacane [email protected] Subject: [amsat-bb] Re: LF Satellite ideas? To: [email protected] Date: Sunday, 12 December, 2010, 2:13
--- On Sat, 12/11/10, Bob Bruninga [email protected] wrote:
Is 137 KHz possible from space?
Bob,
My understanding is that LF and VLF emissions of terrestrial origin don't get beyond the 'D' layer, even at night. In fact, the 'D' layer acts as a reflector, rather than an attenuator at these frequencies. Cosmic background radiation maintains sufficient 'D' layer ionization at night.
However, your post reminded me of project INSPIRE, which was a plan to transmit VLF signals from the Space Shuttle back in 1992 using a pulsed electron gun in the payload bay. Details on project INSPIRE can be found here:
http://theinspireproject.org/index.php?page=faq
I'm not sure how this would penetrate the ionosphere except through brute force.
Nevertheless, compatible receivers are simple to build and readily available.
73, de John, KD2BD
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_______________________________________________ Sent via [email protected]. 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 _______________________________________________ Sent via [email protected]. 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