| 摘要 |
PURPOSE:To adjust the direction of a receiving antenna accurately and easily by knowing the electric field intensity of a radio wave received by the receiving antenna only by connecting a simple instrument to a terminal for testing provided to an outdoor unit. CONSTITUTION:An indoor unit 30 detects the reception level of the radio wave received by the outdoor unit 2 and sends out the detected reception level to the outdoor unit, which is provided with the testing terminal 13 which outputs the reception level supplied from the indoor unit. A low-frequency signal which varies in amplitude with the reception level of the radio wave appears at the testing terminal 13. For this purpose, the amplitude of the low-frequency signal led out to the testing terminal 13 is measured to know the reception level of the receiving antenna 1, i.e. electric field intensity of the received radio wave. Therefore, the direction of the receiving antenna 1 is so adjusted that the indicated value of an AC voltmeter is maximum, installing the receiving antenna 1 accurately in the arrival direction of the radio wave. |
