| 摘要 |
PURPOSE:To enable efficient operation by making equal the effective height of the antenna to the height of iron tower approximately, through the connection of coil to the base of the iron tower of umbrella antenna and connecting another end of the coil to the lower end of each conductor radially via the feeding line. CONSTITUTION:The coil L is connected in series to the base of the iron tower T, and the part between the other end of the coil L and the lower end of each conductor L. The reactance value of the coil L is set so that the electrical length of the electric path consisting of the coil L and the iron tower T is almost equal to the electrical length of the electric path consisting of the conductor K+feeding line Fk. When power from the oscillator S from the exciting point R of the junction between the coil L and the feeding line Fk is fed, the same directional current flows to the both electric paths, and the current node N appears at the top P of the iron tower T since the electrical length of the both electrical length is almost the same. Accordingly, the effective height of the antenna is almost equal to the height of the iron tower T, allowing to operate with much efficiency. |
