Covert room transmitters are room transmitters that can send voice conversations from within a room to a recipient that needs to hear the conversation, or record the conversation with a recording device. Covert room transmitters are not easy to identify when placed discretely to send the conversation over the air to a radio receiver by means of an antenna. In addition, a covert room transmitter can also use the electrical wiring of a room to send its signal, over the mains lines, as observed in the operation of a mains transmitter.

A Covert Room Transmitter can operate for a long time, broadcasting conversations over a span of days. A Covert Room Transmitter can operate continually, or can be made to operate as a voice activation transmitter, in order to prolong the life of its operation. When using a Covert Room Transmitter, the user should understand the environment the covert room transmitter will be operating under, that way the user will be able to determine how well the transmitter will perform. For example, if a covert room transmitter is being used within an office building, the construction of the building may hinder some of the transmitter's abilities. When using a room transmitter where there are cell phone towers or radio towers within the vicinity, then the transmission abilities may be reduced.