On Mon, 14 Jun 2004 14:33:22 -0500, jerry Wass
wrote:
/// I am wondering just how much energy the radio
system is being exposed to flying by the transmitting elements a mile
away laterally, and how prudent that is for the longevity of the
components. Lets use 50,000 watts if that is appropriate for the example.
Dave
///
If 50 kw were distributed through a spherical surface of 1 mile in
radius, what would the power intercepted by one square yard?
(arbitrary cross-section value for a 1/4 wave whip...)
power times Antenna cross-section / Extended surface area
[4/3 pi r squared] = 4 milliwatts
Into 50 ohms, that would amount to v^2/50 = 0.004
v^2 = 0.2 v^2 so V = 0.4 volts very roughly....
Brian W
And the sensitivity of most receivers is rated in MICRO volts ! ??
Compare with the ultimate sensitivity of the human eye: one quantum
in the visible (at low quantum efficiency), but it can stand a
fleeting exposure to 1400 watts/meter^2 i.e. direct sunlight
That is an extra ordinary range.
Brian W
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