Crystal controlled Listening bugs Note

To be able to listen in on the transmitter's audio surveillance transmission, the receiver need to be tuned to the same frequency as the transmitter.

A crystal controlled transmitter will stay tuned to the same frequency it was meant to.

Non crystal-controlled transmitters will eventually drift in frequencies and once that happened,you will not be able to pick up the transmission with your receiver.

You can re-tune it to the original frequency but you will need to take it outof its "hidden location".

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