On Fri, 18 Jul 2003 11:54:52 -0700, Roy Lewallen
wrote:

How about light bulbs, solar panels, thermocouples, batteries, fuel
cells, and fireflies?


A light bulb is a transducer? Amusing example of non mechanical
translation until you touch it, then the phonons exhibit that
mechanical transfer in the form of heat. Common experience as your
hand approached that opportunity would have revealed that fate through
radiation and that is neglecting another mechanical form of energy
transmission offered. That other form is convection.

You have not offered counter-examples, you simply ignore positive
examples. I've spent nearly 30 years in the field of Electro-Optics
with contracts as recent as this year. I've yet to see the trade
press or research commonly describe these items as "transducers."
That is not to say I would reject any such reference, but I would say
few are treading that path to attend a philosophical distinction that
is largely semantic.

Stick with antenna as transducer, it makes a fine metaphor.

73's
Richard Clark, KB7QHC

Roy Lewallen, W7EL

Tarmo Tammaru wrote:
Any transducer I can think of offhand converts between mechanical energy and
electrical energy, as for instance a loudspeaker, microphone, mechanical
filter, etc.

As for the impedance of free space, one way to build a stealth aircraft is
to cover it with material that has a resistivity of 377 Ohms/square. Then
there is no reflection

Tam/WB2TT