[Lowfer] Free Energy/QST October 1999

John Davis [email protected]
Sun, 10 Mar 2002 17:15:16 -0500


>
>Say you have a one watt transmitter with a 100% efficient antenna so that
one
>watt is "transmitted". Furthermore, say that 1000 receivers in the far
field
>are tuned to that signal, each receiver's antenna input circuit "absorbing"
>one milliwatt of power (surely a receiver's antenna input circuit, even
>though decoupled from the transmitting antenna by distance, "sinks" a
finite
>amount of power, especially if it is tuned to resonance on the
transmitter's
>frequency). One milliwatt is probably outrageously high, but for the sake
of
>arguement let's say that this is the case. If 1000 additional identical
>receivers were added, would the signal strength to all receivers drop by 3
>db?
>


Yes and no.  Without enmeshing ourselves in conundrums of
action-at-a-distance and problems with causality, it is necessary to caution
right up front that full recovery of the radiated power with the 1000
receivers means enclosing the entire transmited signal in a spherical or
hemispherical (depending on whether a dipole or monopole transmitting
antenna is used) shield, consisting of all the receive antennas.  Otherwise,
power will escape the system, and the 1 milliwatt per receiver that you
postulate will simply be impossible by definition.

If you then double the number of receivers, you will have to double the
surface area of the shield to accomodate the number of antennas, and so you
will indeed decrease the power per receiver by 3 db.

But in a real world situation where the receivers are physically isolated,
this relationship does not exist.  The captured power per receiver will
simply be an insignificant fraction of the total.  Multiplying the number of
receivers will make no measurable difference at all until you begin to
physically enclose the volume of space in which the radiator resides.

73,
John