| 摘要 |
PURPOSE:To avoid the effect of the tide level and thus obtain the steady wave radiation characteristics, by varying the electric capacity of the top loading provided at the top area of the antenna in accordance with the change of the tide level. CONSTITUTION:Tide level signal S1 supplied from tide level detector 21 is sent momentarily to control device 22, and arithmetic circuit 23 obtains the degree of opening of umbrella-type substance 4, i.e. the position of moving component 7 by which the capacity of loading 20 may have the optimum value according to the tide level, and then delivers position signal S2. Signal S2 is then supplied to moving component driving device 25 via amplifying circuit 24 to give the positioning to component 7, and then obtains the optimum degree of opening for substance 4. On the other hand, transmitter 26 performs an operation through arithmetic circuit 28 for both the coupling and the tuning of the antenna based on the feed current value of the antenna detected by current detecting circuit 27. And an automatic adjustment is carried out for matching circuit 29 based on the arithmetic result. Thus the steady wave radiation characteristics can be obtained with no effect of the tide level. |
