| 摘要 |
Apparatus for detecting and recording an electromagnetic radiation spectrum in the VLF and ELF range including a ferromagnetic cored antenna in a variably tuned circuit, a drive motor for sweeping the tuning and actuating a sweep marker, a time reference, and a voice and data amplifier. The output signals of these devices are fed into a multichannel recorder. A plurality of such variably tuned circuits may be used.
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