science

Radio beacon

Radio beacon is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Radio beacon rather than just read about it. In short: In navigation, a radio beacon or radiobeacon is a kind of beacon, a device that marks a fixed location and allows direction-finding equipment to find relative bearing. It is a fixed-position radio transmitter which radiates radio waves which are received by navigation instruments on ships, aircraft or vehicles.

Key takeaways

Radio beacon belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Radio beacon to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Radio beacon from memory before moving on to harder problems.

Reference excerpt

In navigation, a radio beacon or radiobeacon is a kind of beacon, a device that marks a fixed location and allows direction-finding equipment to find relative bearing. It is a fixed-position radio transmitter which radiates radio waves which are received by navigation instruments on ships, aircraft or vehicles. The beacon transmits a continuous or periodic radio signal on a specified radio frequency containing limited information (for example, its identification or location). Occasionally, the beacon's transmission includes other information, such as telemetric or meteorological data. Radio beacons have many applications, including air and sea navigation, propagation research, robotic mapping, radio-frequency identification (RFID), and indoor navigation, as with real-time locating systems (RTLS) like Syledis or simultaneous localization and mapping (SLAM).

Types

Radio-navigation beacons The most basic radio-navigational aid used in aviation is the non-directional beacon or NDB. It is a simple low- and medium-frequency transmitter used to locate airway intersections and airports and to conduct instrument approaches, with the use of a radio direction finder located on the aircraft. The aviation NDBs, especially the ones marking airway intersections, are gradually being decommissioned and replaced with other navigational aids based on newer technologies. Due to relatively low purchase, maintenance and calibration cost, NDBs are still used to mark locations of smaller aerodromes and important helicopter landing sites. Marine beacons, based on the same technology and installed in coastal areas, have also been used by ships at sea. Most of them, especially in the Western world, are no longer in service, while some have been converted to telemetry transmitters for differential GPS. Other than dedicated radio beacons, any AM, VHF, or UHF radio station at a known location can be used as a beacon with direction-finding equipment. However stations, which are part of a single-frequency network should not be used as in this case the direction of the minimum or the maximum can be different from the direction to the transmitter site.

ILS marker beacons

A marker beacon is a specialized beacon used in aviation, in conjunction with an instrument landing system (ILS), to give pilots a means to determine distance to the runway. Marker beacons transmit on the dedicated frequency of 75 MHz. This type of beacon is slowly being phased out, and most new ILS installations have no marker beacons.

Amateur radio propagation beacons

An amateur radio propagation beacon is specifically used to study the propagation of radio signals. Nearly all of them are part of the amateur radio service.

Single-letter high-frequency beacons

A group of radio beacons with single-letter identifiers ("C", "D", "M", "S", "P", etc.) transmitting in Morse code have been regularly reported on various high frequencies. There is no official information available about these transmitters, and they are not registered with the International Telecommunication Union. Some investigators suggest that some of these so-called "cluster beacons" are actually radio propagation beacons for naval use.

Space and satellite radio beacons Beacons are also used in both geostationary and inclined-orbit satellites. Any satellite will emit one or more beacons (normally on a fixed frequency) whose purpose is twofold; as well as containing modulated station-keeping information (telemetry), the beacon locates the satellite (determines its azimuth and elevation) in the sky. A beacon was left on the Moon by crew of Apollo 17, the last Apollo mission, transmitting FSK telemetry on 2276.0 MHz

Driftnet buoy radio beacons

Driftnet radio buoys are extensively used by fishing boats operating in open seas and oceans. They are useful for collecting long fishing lines or fishing nets, with the assistance of a radio direction finder. According to product information released by manufacturer Kato Electronics Co, Ltd., these buoys transmit on 1600–2850 kHz with a power of 4-15 W. Some types of driftnet buoys, called "SelCall buoys", answer only when they are called by their own ships. Using this technique the buoy prevents nets and fishing gears from being carried away by other ships, while the battery power consumption remains low.

Distress radio beacons

Distress radio beacons, also collectively known as distress beacons, emergency beacons, or simply beacons, are portable, battery-powered radio transmitters carried by ships, aircraft, hikers or cross-country skiers, used in emergencies to locate people in need of immediate rescue. In the event of an emergency, such as an aircraft crashing, ship sinking, or a hiker or skier becoming injured or lost, the transmitter is activated and begins transmitting a continuous distress radio signal, which is used by search-and-rescue teams to quickly locate the emergency and render aid. The basic purpose of distress radio beacons is to rescue people within the so-called "golden day" (the first 24 hours following a traumatic event), when the majority of survivors can still be saved. There are three kinds of distress radio beacons:

EPIRBs (emergency position-indicating radio beacons) signal maritime distress ELTs (emergency locator transmitters) signal aircraft distress PLBs (personal locator beacons) are for personal use and are intended to indicate a person in distress who is away from normal emergency response capabilities (i.e. 911) The largest distress beacon system is the international Cospas-Sarsat search and rescue satellite system. Consisting of about 67 Earth-orbiting satellites carrying transponders and signal processors operated by 45 member nations, it can determine the location anywhere on Earth of a distress beacon transmitting on the Cospas-Sarsat distress frequency of 406 MHz. When it detects a beacon, the Cospas-Sarsat system calculates its location and quickly forwards the information to the local search and rescue (SAR) authorities, who find the emergency and perform the rescue. Cospas beacons also radiate a 121.5 MHz homing signal used by SAR teams with direction finding equipment to home in on the location. With first generation beacons, the satellites are able to locate the beacon with an accuracy of about 2 km (1.2 mi). However the latest generation of beacons, called emergency position-indicating radiobeacons (EPIRB or GPIRB) carry GPS and transmit their location to within about 100 meters.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Radio beacon

Start with the simplest possible case. Write down what Radio beacon claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Radio beacon before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Radio beacon ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Radio beacon

In research: Radio beacon appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Radio beacon in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Radio beacon is common in secondary-school and first-year university syllabi. It links to neighbouring topics Beacons, Navigation, Radio frequency propagation, so understanding it makes those chapters shorter.
In everyday life: Look for Radio beacon outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Radio beacon in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Radio beacon means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Radio beacon out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Radio beacon in simple terms?

Why does Radio beacon matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Radio beacon?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Radio beacon.