The telepathic signal transmitter, which Tifflor carried around with him as a sort of parapsychological beacon, was working at normal power.

Stan had three airtight miniature signal transmitters.

Stan has already left a signal transmitter on the block itself.

They were on the alert for the three small signal transmitters which Stan had left at strategic locations during their first trip through the branching tunnel.

And Agarves had led the kidnappers to the djedida without knowing it, a secret signal transmitter hidden in the new boots she'd given him.

If he were traveling with just one, they would have to use the complete signal transmitter and he might be able to grab it.

But I'll bet I could fashion a simple signal transmitter.

Line of sight obstruction - Anything that blocks the space between the signal transmitter and receiver can interrupt communication.

The device in his hand might not be a simple signal transmitter.

He was a signal transmitter in a known position.