Tesla's ether is rather difficult to define. Indeed, after researching
and reading all of the data I could find on how Tesla viewed the ether,
I only came up confused and guessing (I find the man to have been
diabolically vague on this point.)

However, my best guess is that Tesla's ether is akin to a three
dimensional model of "Newton's Balls of Force." For those not
acquainted with physics labs and the balls of force, Google awaits you.

But, my guess is that Tesla pictured the ether as composed of particles,
indeed, logic dictates it must be composed of some sort of basic
building blocks (given you can muster the faith the size of a mustard
seed in the ether's existence.) These particles are either resting
against each other, or their "force fields" are (since we can't see
them, we must guess-anything is possible.) Now, if a force is created
which can act against these particles which the force contacts, the
force will be conducted into the next layer of particles, then those
particles will again influence the next layer of particles, and so-on
and so-on. the same way Newton's Balls of Force react to a force
applied to the ball at either end of the "string" of balls and conduct
the force through all of the balls and into the far ball. Now, the
force "flowing" though these layers of particles can be viewed as a
"wave" but, when the farthest layer of ether particles lays against
material of our universe (matter we can see, touch and which we consider
real) it will act as a force of the particles of the ether "striking" or
"impinging" the "real matter." Much like the far ball in the sting of
balls of force would do if "touched" by some other material object at
the far end from the applied force. Indeed, the force "flowing" though
the sting of the balls of force is much like the "ether wave" I am
attempting to describe here; when the "wave" has no more balls of force
to "travel" though, the end ball containing all the force from the
"wave" must move in an attempt to "dispose" or "convey" its' energy
into some form of matter.

Now, liken all the above to light. Light travels as a wave in the
ether, yet when striking a surface of some matter it behaves much as
particles would when striking such a surface. Strangely enough, we
still ponder this mystery to this very day. why light behaves both as a
wave and as a stream of particles?

The above is kludged together and is difficult, probably, for others to
grasp on a first reading, and I admit this reflects much of how my
thinking is going when attempting to grasp how Tesla was viewing things
when he wrote about "frequency", "vibrations" and such in his works and
notes. however, from the above, I believe one can imagine how Tesla
would see an antenna interacting with the universes ether and
"transmitting" its "wave".

Now, all of that said, how the "Einstein Antenna" would function would
even be more difficult to comprehend. sometimes leading one to come up
with "magic numbers" to describe it in mathematical terms.

But, if one ponders the above to terrible depths, one is left with the
expectation of finding the ether's particles to exhibit no mass
what-so-ever, and frankly, I find that impossible. go figure.

Or, consider I just made the above up! Or, I just dreamed it all! Or,
Tesla never said any of that at all! grin

JS