Re: Longitudinal Waves

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Richard Wayne Wall by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rwall-at-ix-dot-netcom-dot-com>



Dave and List,

Dave T wrote:

What are you going to do to prevent normal EM pickup of the radio waves?
Two wires spaced 1/2 wavelength apart, oriented at right angles to the
source sounds like it'll pick up normal EM waves just fine.
 
The longitudinal wave has no voltage associated with it, so due to the
quarter wave construction (more or less) of a radio antenna, the zero
voltage will be near the level of ground.  Placing my long wires near the
ground should help eliminate the EM and RF waves

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Dave, different types of sensors and instruments have to be designed and
used 
for detection of these longitudinal waves.  Your sensor/detector must
totally 
reject any EM signal.  As such, it must only detect varying longitudinal E
signals.  Also, you must always be certain as to the reference point that 
you are measuring against and the exact geometry of the system.

A longitudinal wave in space will translate into voltage when it contacts 
a metallic sensing device.

Fortunately, there are very cheap extremely high impedance (teraohms)
mosfet 
op amps available with CMRRs in the 90 - 120 dB range.  With simple circuits
and these very high CMRR, you can literally null out any spurious EM
signals.

These capacitive sensor/detectors open up a whole new area of experiment
and 
exploration.

RWW