FMUSER INTERNATIONAL GROUP INC
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Equipment You’ll Need In A Radio Station
If you think of something missing from this list, please post it in the comments below.
Table of Contents
In the studio…
In the studio…
At the heart of any studio is the audio console (sometimes called a radio panel, sound panel, or sound desk). This is the interface the radio announcer (or panel operator) uses to control what’s heard on air. Every channel represents one “input”. The fader (slider) attenuates or amplifies the incoming signal.
Radio Audio Consoles are very different from a regular PA or Live Sound audio console, and are often more expensive than PA audio consoles as they are purpose-built for on-air talent ease of use. When you turn a microphone on or off, a radio console will mute any speakers and illuminate an “on air” light. When you turn a CD Player, Phone or Computer channel on, often it will “trigger” that input so it starts playing immediately.
While analog audio consoles have the physical audio flow directly through the console’s circuitry, many radio stations now use Digital Audio Consoles – these are actually a remote control for a Mix Engine (often located in the rack room).
A microphone captures sounds from the studio and turn it into electrical impulses. Broadcast microphones are designed a little differently to PA microphones, as issues such as feedback (the squealing sound that can come through speakers) isn’t an issue in a studio.
Experienced audio announcers will often have a favourite microphone. Common microphones include ElectroVoie RE20, Sennheiser MD421, and Rode Broadcaster.
Studio microphones are often mounted on a special arm that keeps the microphone at the correct height. These arms often extend over the audio console, computer monitors, and other equipment – leaving plenty of table space free for equipment and paper.
Playout & Automation Software
The computer system that plays back music, spots (ads, promos, etc.) and sweepers (the little voice-overs played between songs) is called a Playout System or Automation Software. These are specially designed computer programs that allow for continuous playback of audio, with a lot of granular control for Announcers and Programme Directors.
At the heart of any Automation System is the “log”. This is a sequential list of all audio files and commands that need to be played at certain times. All music played on a commercial radio station will be pre-programmed by the Music Director and loaded into the log. A separate person will often load all advertisements into the same log.
Most automation systems also contain a music database, hot keys (to play ad-hoc audio), an audio editor, segue editor (to change the mix between different elements), interfaces for website and RDS data, and a lot more.
Radio Equipment: Rack Computer
The most common piece of equipment in any radio station is by far the computer. These come in many shapes and sizes, and can perform a whole range of broadcast functions. They have become popular, in part, because they are commoditised (and thus much cheaper than broadcast-specific boxes). Here’s some things you can do on a computer in a radio station:
Dead air detection
Emergency audio playback
… and so much more!
Computers in a rack room will often be in rack-mounted server form factor, even for studios workstations. Due to heat and noise requirements in studios, it’s preferable to keep all studio computers physically located in the rack room and simply extend their control with KVM Extenders.
Power SWR Meters
To ensure output of a station is somewhat consistent, radio studios contain different Level Meters. These allow the announcer or panel operator to see if their audio is too loud or too quiet at any given time. Often, you’ll have multiple meters showing the levels at different points in the signal chain.
Some radio stations also provide phase meters along side level meters. This helps you detect mono content, and spot any problems in source material that are likely to cause issues with the stereo image.
Studio Monitor Speakers
Studio Monitor Speakers provide an easy way to hear what’s going to air without headphones. Often, these are very high quality speakers so any abnormalities in sound quality can be detected.
Studio Monitor Speakers are automatically muted whenever a microphone is turned on. As a result, anyone in a studio needs headphones to hear what is going to air. Headphone selection is often a very personal decision based on your preferences in comfort and frequency response.
On Air Light
How do you know a mic in the studio is live? There’s a light especially for that! This light is automatically turned on/off by the audio console whenever a microphone channel is turned on. Usually you’d have at least one light inside the studio, and one outside.
CD Players, DAT Machines, Mini Disk Players, and Turn Tables
Radio Equipment: CD Player
While most pre-recorded audio these days is played off a computer, it’s not uncommon to find these playback devices in a studio (even just as a backup, or a way to capture old archival material). Playback of these devices is usually triggered directly from a button on the audio console.
Digital DJ Controller Dish Machine
Some radio stations use a dedicated microphone audio processor for each microphone. This keeps the levels consistent, and helps tailor the sound.
A KVM (Keyboard/Video/Mouse) Extender allows remote access and control of a computer’s keyboard, mouse and video output. This is typically achieved by a pair of proprietary boxes communicating over a dedicated un-switched Cat6 cable. Sometimes you also see IP-enabled KVM Extenders, which are compatible with network switches and routers.
Broadcast Audio Processor
The Audio Processor is usually the last piece of equipment used before your audio is transmitted. Broadcast audio processors contain speciality multi band compressor/limiters, but also have a lot of “magic” features to give your station that competitive edge. Most stations want to be the loudest, and the big Audio Processor manufacturers all claim to be the loudest and clearest.
While traditionally you’d have a dedicated box for processing, some vendors are now selling software-based processors. If you’re on a budget, check out StereoTool. If you have a lot of money to spend and want a dedicated box, look at Orban and Omnia.
RDS (Radio Data System) is a way of sending ASCII text and other metadata to compatible radio receivers. It encodes a 1187.5Bps data stream onto the 57Khz subcarrier (third harmonic of the 19Khz FM Stereo Pilot signal). Stations use RDS to encode the station name, song data, program guide and traffic information.
RDS Encoders are sometimes built into your FM Audio Processor. If you have an external RDS Encoder, it needs to be connected into the SCA input on your Stereo Generator or Processor.
At the transmitter site…
Studio Transmitter Link
Radio Equipment: STL Antenna
Typically a station would have multiple links in different formats to ensure there is never a break in transmission.
FM Stereo Generator
Radio Equipment: FM Stereo Generator
A FM Stereo Generator takes a stereo audio signal, and converts it into the FM Baseband format. This contains the L+R (Mono), L-R, and 19Khz Stereo Pilot Tone. A Stereo Generator will have a BNC output, which can be connected directly into your Exciter.
Often the Stereo Generation will be done in the Audio Processor, and sometimes in smaller FM transmitters it can also be done directly in the transmitter.
The FM Exciter takes the FM Stereo Baseband signal (from your Stereo Generator, perhaps via the Composite Switcher), modulates it on your licensed frequency. FM Exciters generally output a few Watts of power, and can be used without a separate Power Amp on low power stations.
FM Transmitter Power Amplifier
The FM Power Amplifier (PA) takes the signal from the FM Exciter and amplifies it to your licensed power. These days, FM Power Amplifiers are usually built into the Exciter. However, it’s important to note the difference in function even if they do live in the same box.
If you have multiple FM Stations sharing one antenna array, you need an Antenna Combiner. This takes the high-power output from every station’s FM Power Amplifier and merges it together so it can connect into the one FM antenna array. They typically contain filters to ensure each transmitter isn’t spewing out RF outside of it’s expected frequency range.
Radio Equipment: FM Antenna Array
FM can be transmitted with just one antenna, but this isn’t always optimal. By adding more antennas to the FM system you’re actually adding additional gain. This means more power without buying a bigger transmitter (sort of). For example, a 3dB gain means the EIRP (actual measured output) is double what you TX PA can output by itself. There’s a lot more to it than this, but remember that extra antennas means more efficient transmission.
If you’re dealing with high-powered transmission systems, you need to keep the transmission line (coaxial cable up to the antennas) pressurised. This ensures impurities are kept out of the cable. The pressurisation can be done with an air compressor, or a bottle of nitrogen. Coaxial cable manufacturers (such as Andrew Helix) have specific recommendations based on the type of cable, power output and environmental factors. This isn’t usually necessary for low power FM stations.
An Uninterruptible Power Supply (UPS) provides constant power to all equipment. If you have inconsistent power from the grid, pick an Online UPS – these constantly run power through the battery and inverter ensuring equipment is always protected and power filtered. An offline UPS simply switches to battery power when there is an outage.
The tuner remotely controls two bands with time and timing, and outputs clear stereo audio, making the sound more beautiful.