From: O'Reilly John E NORC >Has anyone ever tried transmitting from above water to underwater and vice >versa? No doubt billions of $$$ has been spent by the Navy. Don'cha know 8^) > I am thinking of using 2m amateur transceivers on either end, and >I'm wondering what kind of range I can get with a couple of watts. Inches? The conductivity of the water no doubt means induced opposing currents will shield and reflect. The relative dielectric constant for water is approx. 80. Severe mismatch. > Also, if >I put one half of the antenna (either ground or radiator) in the water, will >that make a difference? Probably a lot, if you match impedances from above water to below water. You can check out references for ground penetrating radar antenna. They launch waves into a large mismatch. Another interesting, far out possibility that occured to me after reading some books on ultrawide band (UWB) or impulse radar is that solitons may be generated, and have greatly reduced propagation losses (relative to non-solitons). Dielectrics and magnetic materials have a transient & steady state response. Unpolarized, a tensor is created at twice the exciting frequency. Just put a gap in a 60 Hz iron transformer core, and you feel a 120 Hz oscillation as both clockwise and counter clockwise currents' flux stress the magnetic core, in the same direction. In other words, power is transduced from magnetic flux into mechanical strain. And the compression resulting from the strain changes the permiability or the permittivity of the media, be it magnetic or dielectric. Such a nonlinear media may support solitons. Certainly differences in propagation have been noted due to the transient and steady state material characteristics, such as 'induced radio transparency' and 'tunneling'. Some papers and references are available from http://www.aetherwire.com . You must search around a bit to find the online CD Rom with them. Scott **************************************************************** Freedom is pursuing your carrot, not running from a stick. The mob only rules what its members are allowed to achieve. Physics - the manifold ways the odds always get even... **************************************************************** >TIA >John > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! >email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu