Low-current devices were used as signal detectors, first used in radio by Fleming in 1904.

Multiple matches per set serve as independent signal detectors and provide a possibility to capture statistical uncertainties.

We need a working force to build an S-wave signal detector, but the intelligence of this planet has never worked in space.

You know what is needed for the creation of an S-wave signal detector.

Build the signal detector, and use it.

Should no space-faring intelligence be located, within this galaxy, build a superluminal signal detector.

She had seen ads for the type of cellular signal detector Ken had mentioned.

And I think he probably does have a cellular signal detector up there.

Both vehicles would be equipped with high-frequency signal detectors to trace the direction of the source of any instructions an enemy might send the crow.