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On Wed, 16 Jan 2008 10:42:32 -0500, "Jim"
wrote: I know how to measure amplitude or time with a scope. I just can't figure out how to measure distance. You don't measure distance on the scope, it measures time. Given the speed of the wave, typically 300,000,000 meters/sec, it is easy to calculate distance, e.g., a 1 microsecond wave equals 300 meters wavelength. |
#3
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posted to rec.boats
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Wayne.B wrote:
On Wed, 16 Jan 2008 10:42:32 -0500, "Jim" wrote: I know how to measure amplitude or time with a scope. I just can't figure out how to measure distance. You don't measure distance on the scope, it measures time. Given the speed of the wave, typically 300,000,000 meters/sec, it is easy to calculate distance, e.g., a 1 microsecond wave equals 300 meters wavelength. True, except when the dielectric constant (relative permittivity) of the medium is higher than free space, then the wavelength is reduced by 1/sqrt(Er). Common coax cable dielectrics usually have an Er ~ 2.2 and most PC board material is about 4.4 or so. |
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