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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