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Old April 9th 07, 09:39 PM posted to rec.radio.amateur.antenna
Jim Kelley Jim Kelley is offline
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First recorded activity by RadioBanter: Jul 2006
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Default Constructive interference in radiowave propagation



Cecil Moore wrote:

Jim Kelley wrote:

The quote from Born and Wolf that Cecil cites supports the 'profound'
notion that (E1 + E2)^2 / (E1 + E2) = 4.



There sure appears to be something wrong with that
equation, Jim. If E1 = E2 = 1 volt, then you have
4 / 2 = 4 which seems a bit wrong, if you don't
mind me saying so. What dimensions does your '4'
above have? Seems it would have to be 4 volts.

Assuming E1 = E2, I think what you meant to say was:

(E1 + E2)^2 / E1^2 = 4 (dimensionless)

which is what Born and Wolf say in equation (17)
chapter 7. Please note that is total constructive
interference as defined by Hecht in "Optics"

Also please note that if those signals are the opposite
phase:

(E1 - E2)^2 / E1^2 = 0

That's total destructive interference as defined
by Hecht.


Right. So do you get the point, or not?

73, ac6xg