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For those of you who may be unfamiliar with the mathematics of
transmission lines, download program TWOLINES and enter the following practical values - Line-1 represents the loading coil. Line-2 represents the whip to be pruned for 1/4-wave resonance. Enter Zo1 = 6000 ohms, a practical value. Enter electrical length L1 = 0.15 wavelengths. Enter attenuation = 0.1 dB for wire loss in coil. Enter Zo2 = 400 ohms, a practical value. Enter electrical length L2 = 0.0077 wavelengths. Enter attenuation = 0.001 dB Enter open-circuit load resistance = 100 Megohms and load reactance = 100 Megohms. To check that the circuit is in 1/4-wave resonance, vary plus or minus length of Line-2 for zero or minimum input reactance. The input resistance of the coil or Line-1 is about 16 ohms, a typical value. But L1 + L2 = 0.1577 wavelengths = only 57 degrees. The missing 90 - 57 = 33 degrees are just not needed for resonance. So why is everybody making such a fuss about it? ---- .................................................. .......... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp .................................................. .......... |
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