Front-to-back ratio: Difference between revisions
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FBR is of course meaningless for omnidirectional antennas. | FBR is of course meaningless for omnidirectional antennas. | ||
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Latest revision as of 16:59, 8 April 2009
Related wiki pages: Antennas, Gain, Propagation, SWR
Front-to-back ratio (FBR) is a measure of how effectively a directional antennas, eg Yagi, Log Periodic (LPDA), Dish or Parabola projects RF energy in the desired direction.
It is calculated as the ratio of the maximum directivity of the antenna to the directivity in the opposite direction.
To quantify FBR, a radiation pattern plot is drawn.
FBR = maximum radiation (dB) in the forward direction - maximum radiation (dB) at <math> 180^0 </math>
FBR is of course meaningless for omnidirectional antennas.
| Antennas | |
| Design | Beam * Dipole * Dish or Parabola * DDRR * Log Periodic (LPDA) * Loop * Mobile and portable * Omnidirectional * Panel * Quad and Quagi * Screwdriver * Small tuned loop * Vertical * Yagi-Uda * Wire and random wire antennas |
| Installation | Antenna Tuners * Capacity hats and loading coils * Cavity filters * Coaxial Cable * Feedlines * Rotators * Towers and Masts * VK2ACY - G5RV coupler |
| Theory | Front-to-back ratio * Impedance matching * SWR * Tower design * Vertical Antenna efficiency * Wire comparison tables |