Ramsey Electronics LEDS1 Manuel d'instructions télécharger pdf (Page 5)

DDF1  5

c = Speed of light

We can calculate how fast the antenna must rotate in order to produce a

given Doppler frequency shift with the following equation

fr = dF x 1879.8/R x f

where

fr = The frequency of the received signal in megahertz

dF= The Doppler shift in Hertz

R = Radius of antenna rotation in inches

= Carrier frequency of the received signal in megahertz

As an example, let's calculate how fast the antenna must rotate in order to

produce a Doppler shift of 500 Hz at 146 MHz, assuming the antenna is turn-

ing in a circle with radius 13.39 inches.

RF Signal (fo)

Rotation

f o

+ f

- f

(B)

(A)

Figure 1

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Ramsey Electronics LEDS1 Manuel d'instructions Page 5