2. A person whose job is to write official data about things that need to be available for current or future reference: Carol is the official recorder for the local housing advocacy committee meetings and in addition to taking hand written notes, she uses an electrically operated machine to be sure she accurately gets all the information from meetings.
2. A recorder in which a moving electron beam is used to record signals or data on to photographic or thermoplastic film in a vacuum chamber.
3. A device that transfers computer data onto microfilm using an electron beam.
2. A radio device for determining the distribution of virtual height with frequency, and the critical frequencies of the various "layers" of the ionosphere.
A pulse at a certain frequency is transmitted vertically, and the time for its return is recorded on an oscilloscope; another pulse at a different frequency is then transmitted and timed.
The process is repeated until the entire frequency range of interest, usually from about 1 to 25 MHz, has been explored.3. A radio device for determining the distribution of virtual height with frequency, and the critical frequencies of the various layers of the ionosphere.