How does a load coil work?
The coil is built to have an inductive reactance equal and opposite to the capacitive reactance of the short antenna, so the combination of reactances cancels. When so loaded the antenna presents a pure resistance to the transmission line, preventing energy from being reflected.
Does a loading coil radiate?
Speculation is only the first few turns of the loading coil carry significant current because the coil “leaks” magnetic fields and radiates, and this is why the coil Q has little effect.
What is total coil load?
The total amount of heat, in British thermal units per hour, that must be removed from the air by the cooling coils.
How do you calculate coil?
To obtain the coil length we have to divide the result by the section of the coil determined by coil width and thickness. The coefficient 1000 is used to compensate the dimensions in [mm] with the length in [m]. For example, a coil with OD = 1600mm, ID = 508mm and T = 0,6mm results in a length of 3010 meters.
What is antenna loading?
[an′ten·ə ‚lōd·iŋ] (electronics) The amount of inductance or capacitance in series with an antenna, which determines the antenna’s electrical length. The practice of loading an antenna in order to increase its electrical length.
How a loading coil is used to change the electrical length of an antenna?
Loading coil in a cellphone antenna mounted on the roof of a car. The coil allows the antenna to be shorter than a quarter wavelength and still be resonant. An antenna’s effective electrical length can be changed without changing its physical length by adding reactance, (inductance or capacitance) in series with it.
Why is loading coil used in HF mobile antennas?
What is the function of a loading coil used as part of an HF mobile antenna? The coil (inductor) is added to cancel out the capacitance already present in the circuit to try to achieve resonance.
Can a coil be an antenna?
There are at several kinds of antennas which could be described as “coils of wire”, with very different principles. small loop antennas are actual coils (often with ferrite rods), though they are woven differently from power inductors or actuator coils, as self-capacitance must be reduced.
How is HVAC load calculated?
Calculate the HVAC load (House surface in square feet) x (height of the ceiling) (Number of occupants) x 100 BTU. (Number of exterior doors) x 1,000 BTU. (Number of windows) x 1,000 BTU.
What is a latent load?
Latent cooling load is a measure of the amount of energy that is necessary to dehumidify the air in a building, for example, regardless of the outdoor humidity. Cooling load needs to be considered when a cooling system is being dimensioned. Latent cooling load refers to the wet bulb temperature.
What is loaded cable?
To summarize, loading a circuit reduces the energy loss, but also further improves transmission by eliminating distortion effects. Loading coils are designed to increase the impedance or self- inductance of a circuit, and in so doing, balance the capacitance of the cable pair.
How do I calculate coil wire length?
To calculate spring wire length per coil, you must subtract the wire diameter from the outer diameter in order to get mean diameter. Once you have calculated mean diameter, multiply it by pi (3.14); this will give you the length of wire per coil.
Why loading is used with an antenna?
ANTENNA LOADING is the method used to change the electrical length of an antenna. This keeps the antenna in resonance with the applied frequency. It is accomplished by inserting a variable inductor or capacitor in series with the antenna.
What is an antenna coil?
Antenna coils are self-supporting coils that often have a high number of turns. These coils not only provide coupling to any other circuit, but can also be used for increasing inductance of the circuit after insertion. The target resonance of an antenna can be met with the help of an antenna coil.
What is a loading coil?
A loading coil in a small cell phone antenna on a car roof. A loading coil or load coil is an inductor that is inserted into an electronic circuit to increase its inductance.
Where is the loading coil located on an antenna?
The loading coil is often placed at the base of the antenna, between it and the transmission line ( base loading ), but for more efficient radiation, it is sometimes inserted in the center of the antenna element itself ( center loading ).
How do Load loading coils reduce attenuation?
Loading coils inserted periodically in series with a pair of wires reduce the attenuation at the higher voice frequencies up to the cutoff frequency of the low-pass filter formed by the inductance of the coils (plus the distributed inductance of the wires) and the distributed capacitance between the wires.
What is the voltage drop across the loading coil?
The current through the loading coil is not the same at both ends of the coil: it tapers off considerably along the coil. Note that this is consistent with a large voltage drop across the coil (which, if high enough, can be made visible with a fluorescent light). The “Q” of the coil has little or no effect on the voltage drop.