Ramsey Electronics LEDS1 Instrukcja Obsługi Pobierz pdf (Strona 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

1 2 3 4 5 6 7 8 9 10 ... 37 38

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Ramsey Electronics LEDS1 Instrukcja Obsługi Strona 5