1955 年 24 巻 7 号 p. 272-275
The authors have constructed a recording apparatus of atmospherics wave-forms specially designed for the purpose to analyse the lightning mechanism as a generator of atmospherics. As for the principles on which the present apparatus is constructed, they are just the same as those on which a sensitive apparatus to record distant atmospherics wave-forms is constructed. It is, however, essential in the former case to limit the over-all gain of the apparatus in order that the wave-form can be recorded faithfully even in the case of the st-rongest electromagnetic field change caused by a lightning discharge in the vicinity of the station.
In the present apparatus the over-all gain can be varied from +40 to -50 db, hence it can records faithfully the wave-form with the field intensity from 0.3 to 5×104 V/m, using a vertical antenna of about 2m in effective height.
Two cathode ray tubes of the sweep time length of 2 and 20ms are provided, with which the fine structure and the whole aspect of a wave-form can be recorded simultaneously on respective photographic films. The apparatus is equipped with an atmospheric intensity meter to know the occurrence of thunder, and several other devices to collate the records from other arrangements corresponding to the same discharge.