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3.1. General rules.
3.5 If two wires of different diameters are close of each other, despite the fact that their segments are aligned, errors in the computation of the antenna gain and its input impedance may be obtained, especially in the part of the reactance [Ref.5,11]. In models of those characteristics it is advisable to perform the AGT test (see section 7.2) in order to check their validity.
7.2. Average gain test (AGT).
The average gain test is an useful tool to check the validity of a model and it is available in practically all the programs implementing NEC-2
The AGT consists in placing the model, without loads and transmission lines, in the free space (horizontal antennas) or over perfect ground (vertical antennas) and then to simulate the 3D radiation pattern.
In theory, the average gain of a lossless antenna, considering an adequate sampling in all the possible directions of radiation, must be equal to 1. That is, the antenna must radiate all the power provided by the generator [Ref.5,8]. If this rule is not observed, the model probably has defects in the specifications of the generator or maybe the generator is located in the wrong place.
The results of the AGT are interpreted in this way [Ref.7]
AGT < 0.80: the model is questionable and should be refined.
0.80 <= AGT < 0.90: the model may be useful, but can be improved.
0.90 <= AGT < 0.95: the model is usable for most purposes.
0.95 <= AGT < 1.05: the model is likely to be accurate.
1.05 <= AGT < 1.10: the model is usable for most purposes.
1.10 <= AGT <= 1.20: the model may be useful, but can be improved.
AGT > 1.20: the model is questionable and should be refined.
In the case of wideband or multiband antennas, repeat the convergency test in a representative set of frequencies within all the working band of the antenna.
3.1. General rules.
3.5 If two wires of different diameters are close of each other, despite the fact that their segments are aligned, errors in the computation of the antenna gain and its input impedance may be obtained, especially in the part of the reactance [Ref.5,11]. In models of those characteristics it is advisable to perform the AGT test (see section 7.2) in order to check their validity.
7.2. Average gain test (AGT).
The average gain test is an useful tool to check the validity of a model and it is available in practically all the programs implementing NEC-2
The AGT consists in placing the model, without loads and transmission lines, in the free space (horizontal antennas) or over perfect ground (vertical antennas) and then to simulate the 3D radiation pattern.
In theory, the average gain of a lossless antenna, considering an adequate sampling in all the possible directions of radiation, must be equal to 1. That is, the antenna must radiate all the power provided by the generator [Ref.5,8]. If this rule is not observed, the model probably has defects in the specifications of the generator or maybe the generator is located in the wrong place.
The results of the AGT are interpreted in this way [Ref.7]
AGT < 0.80: the model is questionable and should be refined.
0.80 <= AGT < 0.90: the model may be useful, but can be improved.
0.90 <= AGT < 0.95: the model is usable for most purposes.
0.95 <= AGT < 1.05: the model is likely to be accurate.
1.05 <= AGT < 1.10: the model is usable for most purposes.
1.10 <= AGT <= 1.20: the model may be useful, but can be improved.
AGT > 1.20: the model is questionable and should be refined.
In the case of wideband or multiband antennas, repeat the convergency test in a representative set of frequencies within all the working band of the antenna.
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