NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Lu Abel
Date: 2012 Apr 11, 19:19 -0700
Anyone groping for DOD's ELF comm? See Wikipedia below:
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http://en.wikipedia.org/wiki/Communication_with_submarines#Extremely_low_frequencyElectromagnetic waves in the ELF frequency range (3?300 Hz) (see also SLF) can penetrate seawater to depths of hundreds of meters, allowing communication with submarines at their operating depths. Building an ELF transmitter is a formidable challenge, as they have to work at incredibly long wavelengths: The US Navy's system (called Seafarer) operated at 76 hertz,[1] the Soviet/Russian system (called ZEVS) at 82 hertz.[2] The latter corresponds to a wavelength of 3,658.5 kilometers. That is more than a quarter of the Earth's diameter. Obviously, the usual half-wavelength dipole antenna cannot be constructed, as it would spread across a large country.
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--Jared
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