John Nall <jnall01@ALLTEL.NET> wrote:
> There would have to be a directional antenna, but since it would be
> receive-only the length would not be critical.

I don't see how "have to be directional" and "length would not be critical"
go together. For pretty much any transducer, directionality is a strong
function of size.

Furthermore, in underwater acoustics, multipath is going to be a major
issue that needs to be dealt with. The transmitter will need to send out
a narrow pulse (or other signal with high time resolution, such as SS),
and the receiver is going to have to process its input and show when the
*earliest* input signal is the strongest, which means that it's pointed
more or less directly at the source -- although in some circumstances, a
reflected signal could be stronger than the direct path, distorting the
results.

Not a trivial problem at all.

-- Dave Tweed

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