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#1
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Richard Harrison wrote:
We know that a monopole has half the resistance of a dipole. Example: 73 ohms and 36.5 ohms. 790 / 2 = 395. That`s not a resistance, it is only the value of a constant which must be multiplied by (L/lambda) squared to give the radiation resistance of a very short monopole. Does it matter that for a vertical that is 1/2 of the length of the dipole, (L/lamda)^2 is different by a factor of 4? -- 73, Cecil http://www.qsl.net/w5dxp |
#2
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Cecil, W5DXP wrote:
"Does it matter that for a vertical that the length of a dipole (L/lambda)squared is different by a factor of 4?" It doesn`t make a ratio different than two to one in the ratio of resistances of the 1/2-wave dipole to the 1/4-wave monopole. We are not comparing a monopole that is the the length of a dipole with the dipole. We are comparing a monopole that is 1//2 the length of a dipole to the dipole when we make the resistance ratio. The small dipole is working against a perfect ground in Reg`s specification. It would see its reflection in that perfect ground, so its equivalent length is doubled. Kraus` dipole is presumed to be in free space. Best regards, Richard Harrison, KB5WZI |
#3
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Richard Harrison wrote:
Cecil, W5DXP wrote: "Does it matter that for a vertical that the length of a dipole (L/lambda)squared is different by a factor of 4?" It doesn`t make a ratio different than two to one in the ratio of resistances of the 1/2-wave dipole to the 1/4-wave monopole. We are not comparing a monopole that is the the length of a dipole with the dipole. We are comparing a monopole that is 1//2 the length of a dipole to the dipole when we make the resistance ratio. Richard, Balanis doesn't say that the 'L' in the monopole formula is 1/2 the 'L' in the dipole formula. Does Kraus? -- 73, Cecil http://www.qsl.net/w5dxp |
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