[amsat-bb] Re: LF Satellite ideas?

GRAHAM SHIRVILLE g.shirville at btinternet.com
Sun Dec 12 00:52:26 PST 2010

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.

--- On Sun, 12/12/10, John Magliacane <kd2bd at yahoo.com> wrote:

From: John Magliacane <kd2bd at yahoo.com>
Subject: [amsat-bb] Re: LF Satellite ideas?
To: amsat-bb at amsat.org
Date: Sunday, 12 December, 2010, 2:13

--- On Sat, 12/11/10, Bob Bruninga <bruninga at usna.edu> wrote:

> Is 137 KHz possible from space?


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:


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

Visit John on the Web at:


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