What is a frequency converter in satellite communication?

 

Frequency converters form the backbone of all satellite communication. Without them the amount of useable spectrum would be very limited or the cost of infrastructure required to access satellites would be prohibitive. But what are these small devices, and how do they work?

Frequency converter definition

Simply put, a frequency converter is an electronic device that changes the frequency of a signal for satellite transmission. They are typically mounted on the feed arm of a satellite dish – and are used both on Earth and in space to ensure communications can be successfully sent and received.

 

Why are frequency converters so important? 

Because satellites have such wide views of the earth and because other spectrum users had staked claims to lower frequencies satellite communications have been traditionally pushed in to higher and higher frequencies bands. This has given satellites access to a large amount of the public airwaves, but at the cost of being at high frequencies that are expensive to access directly. To make it more cost effective signals are generated at lower intermediate frequency (IF) and then upconverted to a higher radio frequency (RF). Then, when the signal reaches the satellite, if it’s a simple relay satellite, it’s changed again to avoid interference with itself. And finally, when it reaches its destination, the signal is “down converted” back from RF to IF. 

Here’s a simple example:

Say you want to communicate from one computer to another via satellite. The message, represented by 1s and 0s, hits the modem, where it is first “modulated” onto a low intermediate frequency (1 GHz, for example) – and then it is up converted using a “block upconverter (BUC)” to its desired radio frequency (20 GHz, for example).

The signal is also amplified by the BUC and transmitted to the satellite, which changes it a little bit again for its return journey to Earth (19 GHz, for example) – just to ensure it doesn’t interfere with the incoming 20 GHz transmission. When the signal reaches the satellite dish at its ultimate destination, it is amplified again and down converted using a “low noise block downconverter (LNB)” from RF back to IF. And finally, another modem “demodulates” the signal back to usable 1s and 0s. Message received!

 

3 types of frequency converter

1. Up converter – converts a low frequency IF (intermediate frequency) input signal into a high frequency RF (radio frequency) output signal for signal transmission. When an up converter is combined with an amplifier it’s called a “block upconverter” or “BUC”.
2. Down converter – converts a higher frequency RF input signal to a lower frequency IF output signal. When a down converter is combined with an amplifier it’s called a “block downconverter (BDC)” or “low noise block downconverter (LNB)”.
3. Up-down converter – also called a transceiver, an up-down converter combines an upconverter and a downconverter into a single package. Up-down converters are becoming increasingly popular due to their very small size – and are used for applications such as Starlink antennas mounted on cabins and remote properties.

Note: These types of frequency converters are specific to satellite communication. There are other types of frequency converters that convert electrical power – which are not the same thing.

What is RF (radio frequency)? 

Radio frequency is the oscillation rate of electromagnetic radio waves. RF is measured in hertz (Hz), which represent the number of cycles per second when a radio wave is transmitted. The RF spectrum includes frequencies ranging from 30 Hz to 300 gigahertz (GHz) and is divided into bands for easier identification – such as C-band, X-band, Ku-band and Ka-band. Each band is used for different applications. X-band, for example, is used by the military.

What is IF (intermediate frequency)? 

An intermediate frequency is a “stepping stone” in radio transmission or reception. A signal is converted to an intermediate frequency to allow for easier filtering and amplification before final transmission.

 

Frequency converter applications in different industries 

Satellite frequency converters are used in many different industries. Here are some of the most common:

• Aerospace and aviation. Frequency converters are mounted on planes to provide passengers with in-flight WiFi and entertainment. They are also used to provide back-up satellite communication if radio systems go down.
• Military. Key applications include communications in the field and SATCOM-on-the-Move (SOTM) – which can send live, high-definition video and audio from fast-moving vehicles back to base or anywhere in the world. Frequency converters are also used in the remote operation and control of unmanned aerial vehicles (UAVs) and combat drones. 
• Marine. Frequency converters are used by coast guard organizations and search and rescue teams to communicate in open water. They are also used by cruise ship companies to provide passengers with reliable WiFi while at sea.
• Telecommunications. When fibre is not an option, mobile 5G communications and internet can be provided via satellite. Remote villages in northern Canada, for example, use powerful antennas (and frequency converters) on their base stations to connect to 5G over satellite.
• Satellite news gathering. News trucks equipped with large satellite dishes and frequency converters serve as mobile earth stations, allowing journalists to broadcast from any location the truck can reach – live.
• Earth observation (EO). EO satellites use frequency converters to provide data on fires, floods, drought, shrinking glaciers, weather systems and other changes in the environment. They are also used for commercial applications – such as monitoring moisture levels in fields so farmers know where to water first during times of water scarcity.
• Oil & gas. Frequency converters help oil and gas companies monitor pipelines for pressure, leaks, maintenance needs and more in real time – transmitting live data from Internet of Things (IoT) sensors via satellite. They are used to provide backup communication in case of emergency.
• Disaster response. Satellite communication is essential in disaster response management as terrestrial communication is often the first thing to do down. Frequency converters support effective coordination and support for first response teams in the event of disaster – such as earthquakes, hurricanes and war zones.

 

Satellite frequency converters in space 

Frequency converters aren’t just used to transmit communications from Earth to Earth via space. They are used for space-based applications as well – such as monitoring space junk, debris, other satellites and even asteroids – transmitting data and images from space to Earth. They also enable communication between Earth and the International Space Station (ISS) and spaceships. These frequency converters are “hardened” for space, able to withstand extreme temperatures as well as radiation from the sun without faltering.

 

Why choose Orbital Research frequency converters? 

Orbital Research makes frequency converters for the toughest conditions on Earth and in space. Our low noise block downconverters (LNBs) and block downconverters (BDCs) are trusted by military and commercial organizations around the world because they provide reliable, high quality satellite communication with very low phase noise – and because they do not fail. Talk to us about your frequency conversion needs today.