Absolute Converter

Convert between Antenna Factor and Gain in dBi

Antenna Factor

Frequency

dBm-1 for MHz
 

GaindBi

=
\( 20\cdot Log(MHz)-AF-29.79 \)
 

GaindBi

Frequency

dB for MHz
 

AF

=
\( 20\cdot Log(MHz)-Gain_{dBi}-29.79 \)
 

Far-Field Distance

Dipole, Log-Periodic ,or Yagi Antennas

MHz
 

Distancemeters

=
\( 300/(MHz*2*pi) \)
 

Horn Antennas

MHz
Dmeters
 

λ

=
\( 300/MHz \)

Distancemeters

=
\( 2*{D}^{2}/λ \)
 

Find Spot Size

Test Distance

3dB Beam Width

m for °Deg
 

Spotmeters

=
\( 2\cdot Distance_{meters}tan[\frac{Angle_{3dB}}{2}] \)
 

Find Test distance

Spot Size

3dB Beam Width

m for °Deg
 

Distancemeters

=
\( \frac{Spot_{meters}}{2\cdot tan[\frac{Angle_{3dB}}{2}]} \)
 

Find 3dB Beam Width

Spot Size

Distance

m for m
 

°Deg

=
\( 2\cdot tan^{-1}[\frac{Spot_{meters}}{2\cdot Distance}] \)
 
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