ground reflection การใช้

• Additionally, the sets demonstrated a serious problem with ground reflections.
• The net quality of a ground reflection depends on the topography of the surface.
• This provided the important advantage of allowing the radar to avoid ground reflections simply by pointing the antenna upward.
• Their equation did not assume Gaussian distribution nor did it include the effect of ground reflection of the pollutant plume.
• This way the ground reflection would simply be ignored, although at the cost of requiring the transponder to have two antennas.
• For mobility, better range, and for overcoming obstructions and ground reflection, a vehicle mounted version of BFSR has been developed.
• The resulting beam was so sharply focussed, spanning about 10 degrees, that it easily avoided ground reflections at even low altitudes.
• This would also have the side-effect of allowing the radar to avoid ground reflections simply by pointing the antenna away from the ground.
• The ground reflection of an airborne lidar gives a measure of surface reflectivity ( assuming the atmospheric transmittance is well known ) at the lidar wavelength.
• The new radars eliminated problems with ground reflections, allowing the missile to be fired at any visible target, no matter how close to the ground.
• This had the enormous advantage of avoiding ground reflections by simply not pointing the antenna downwards, allowing the fighter to see any target at its altitude or above it.
• Clutter may also originate from multipath echoes from valid targets caused by ground reflection, atmospheric ducting or ionospheric reflection / refraction ( e . g ., anomalous propagation ).
• Clutter may also originate from multipath echoes from valid targets caused by ground reflection, atmospheric ducting or ionospheric reflection / refraction ( e . g ., Anomalous propagation ).
• First introduced in March 1941, it was found that the ground reflection created a sort of artificial horizon on the bottom of the display, a surprising side-effect which proved very useful.
• Instead of the transponder replying on the same frequency, and thus being lost in the ground reflections, it would receive the signal from the radar and then re-broadcast it on a second frequency.
• The ground reflection has an important effect on the net far field radiation pattern in the vertical plane, that is, as a function of elevation angle, which is thus different between a vertically and horizontally polarized antenna.
• Sir Graham Sutton derived an air pollutant plume dispersion equation in 1947 which did include the assumption of Gaussian distribution for the vertical and crosswind dispersion of the plume and also included the effect of ground reflection of the plume.
• Among these, it was found that the strobe would often stick to the ground reflection, and when it did not, would not stick until it had a strong signal at shorter ranges, or might stick to the wrong target.
• Because the antennas were so much more directional than the wide fan-shaped beams of the earlier systems, the entire problem with ground reflections could be avoided simply by ensuring the antennas were always pointed a few degrees above the horizon.
• The approximate impedance required to match a centre-fed dipole antenna in free space ( i . e ., a dipole without ground reflections ) is 73 ?, so 75 ? coax was commonly used for connecting shortwave antennas to receivers.