Glossary

Learn RF terms and their definitions.

Term
Description
Transmitter (Tx) Takes and audio input, encodes it onto an RF carrier signal and transmits it.
Receiver (Rx) Receives RF signals, decodes the audio signal and routes it to an output.
Antenna Maximizes reception of RF signals. Normally tuned to a work with a particular frequency range.
Whip Antenna Omni directional, single polarization antenna.
LPDA (aka Fin) Directional, single polarization antenna.
Helical Very directional antenna with circular polarization to minimize dropouts.
IEM In Ear Monitor. A system that uses a Tx and Rx unit to send audio to a performer. IEM systems are typically non-diversity and mono.
Wireless Mic A handheld or belt pack Tx unit which embeds audio from an integrated mic capsule or plug in mic.
Fiber RF over Fiber allows RF signals to be sent down a fiber cable dramatically increasing range and eliminating signal loss.
Co-Ax Copper cable with a 50 Ohm impedance used to connect RF components together. All Co-Ax cables exhibit signal loss over distance. Signal loss is higher at higher frequencies. For example, a cable that exhibits an 8db loss over 100ft at 400Mhz would exhibit a 16db loss over the same distance at 800Mhz. Co-Ax cable is specified in RG numbers. The higher the number the lower the signal loss over distance.
BNC Bayonet Neill-Concelman the standard connector for RF system components. The BNC connector features two locating pins and requires a 90dg turn to fully seat or undo.
Diversity The use of 2 antennas to maximize RF signal to an Rx unit. There are two basic types Diversity and True Diversity. Diversity places the signal detection circuit after the antenna and before the receiver and sends the strongest antenna signal to the receiver. True Diversity uses two antenna and receiver sets and the detection circuit chooses the best audio signal rather than the best RF signal.
Multi-Zone Diversity Sums multiple sets of diversity antennas to one set of outputs. This allows RF signal to be picked up across many zones.
Quadversity Diversity antenna system but with four antenna/receiver sets instead of two.
Dropout When the RF signal fails to reach the Rx unit with sufficient strength.
DTV Digital Television
UHF Ultra High Frequency, typically 470-698 MHz
VHF Very High Frequency, typically 169-217 MHz
STL Licensed frequency band, typically 940-960 MHz
AM Amplitude modulation
FM Frequency Modulation
White Spaces Gaps in between DTV signals
Scan Captures all the RF signals in an environment. Provides a baseline for frequency coordination.
dBi Decibles in relation to Isotropic antennas
dBd Decibels in relation to Dipole antennas
VSWR (Voltage Standing Wave Ratio) A measure of how efficiently radio-frequency power is transmitted from a power source, through a transmission line, into a load(Antenna). Values go from 1 to infinity. The lower the number the better.
Return Loss The loss of energy reflected back from the load(Antenna). Higher loss indicates that the load is absorbing the energy and not reflecting it back. Higher loss is good.
LPDA (aka Fin) Log-Periodic Dipole Array
AM Amplitude Modulation
FM Frequency Modulation
Interruptible Foldback Interruptible Foldback
IMD Intermodulation
IAS Intermodulation Analysis System
SDR Software Defined Radio
LMS License and Management System
STA Special Temporary Authority
STL Studio Transmission Link - (944 - 952MHz)
SBE Society of Broadcast Engineers
CDBS Consolidated Database System
ULS Universal Licensing System
LMR Land Mobile Radio
T-Band Downlink and Uplink Blocks A-G in Spectrum (Includes Duplex Gap)
DECT Digital Enhanced Cordless Telecommunications (US DECT 1.92 GHz - 1.93 GHz)
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