The brief signal transmitted by a repeater or Gateway transmitter after someone stops talking and before the courtesy tone that the repeater uses to signify that the timer has been reset.
A machine that can convert keystrokes (typing) into electrical impulses. The teleprinter can also convert the proper electrical impulses back into text. Computers have largely replaced teleprinters for amateur radioteletype work.
Television Interference (TVI).
Interruption of television reception caused by another signal.
Temperature Coefficient.
A number used to show whether a component will increase or decrease in value and by how much as it gets heats up in use.
Temperature Compensated Crystal Oscillator (TCXO).
A heated crystal oscillator. Keeping the oscillator at a constant temperature reduces drift and results in better frequency stability.
Temperature Inversion.
A condition in the atmosphere in which a region of cool air is trapped beneath warmer air.
Temporary State of Communications Emergency.
In the US, when a disaster disrupts normal communications in a particular area, the FCC can declare this type of emergency. Certain rules may apply for the duration of the emergency.
Terminal.
1. An inexpensive piece of equipment that can be used in place of a computer in a packet radio station.
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2. Old term for a computer.
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3. Shorting out a fuse holder on a piece of DC powered equipment, then applying voltage the wrong way round!
Thermal Effects of RF Energy.
Body tissue changes that are directly related to heat production when RF energy is absorbed. For example, in extreme cases at high levels of SAR, hyperthermia and tissue damage can occur. It has been demonstrated that in extreme cases, RF-induced heating in the eyes of laboratory animals can result in cataract formation.
Third-Party Communications.
Messages passed from one amateur to another on behalf of a third person.
Third-Party Communications Agreement.
An official understanding between the United Kingdom and another country that allows amateurs in both countries to participate in third-party communications.
Third-Party Participation.
The way an unlicensed person can participate in amateur communications. A control operator must ensure compliance with Ofcom rules.
Ticket.
A slang name for an Amateur Radio licence.
Time Averaging.
Transmitter power is averaged over times of six minutes for controlled RF environments or thirty minutes for uncontrolled RF environments for power density calculations to determine exposure levels.
Time-Out.
To cause the repeater to send the courtesy tone and revert to receive because an operator has transmitted too long.
Time-Out Timer (TOT).
A device programmed in some transceivers that gives an audible warning after a certain (set) time has been reached, aiding the operator to avoid repeater time outs. (Some models revert to receive if the transceiver is still transmitting after the audible warning).
TNC.
1, Terminal Node Controller, a device which interfaces a computer to a transceiver for digital communication and performs a function similar to a modem. See also: Digital Modes page.
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2, Threaded Niell-Concelman (named after its inventors) coaxial connector, the same as a BNC connector, but a threaded locking ring is used instead of a bayonet type. Not commonly found on Amateur Radio equipment.
Problems in an ssb transmitter can be detected by feeding two audio tones into the microphone input of the transmitter and observing the output on an oscilloscope.
TX.
Short hand for transmit, transmitter or transmitted.
