Radio

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General

See also Streaming, Electronics

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  • https://en.wikipedia.org/wiki/Radio_spectrum - the part of the electromagnetic spectrum from 3 Hz to 3000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves, are extremely widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU).

Different parts of the radio spectrum are appointed by the ITU for different radio transmission technologies and applications; some 40 radiocommunication services are defined in the ITU's Radio Regulations (RR). In some cases, parts of the radio spectrum are sold or licensed to operators of private radio transmission services (for example, cellular telephone operators or broadcast television stations). Ranges of allocated frequencies are often referred to by their provisioned use (for example, cellular spectrum or television spectrum).



  • https://en.wikipedia.org/wiki/Longwave - also written as long wave (in British and American parlance) or long-wave, and commonly abbreviated LW, refers to parts of the radio spectrum with relatively long wavelengths. The term is an historic one, dating from the early 20th century, when the radio spectrum was considered to consist of long (LW), medium (MW) and short (SW) radio wavelengths. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.

In contemporary usage, the term longwave is not defined precisely, and its meaning varies across the world. Most commonly, it refers to radio wavelengths longer than 1000 metres; frequencies less than 300 kilohertz (kHz), including the International Telecommunications Union's (ITU's) low frequency (LF) (30–300 kHz) and very low frequency (VLF) (3–30 kHz) bands. Sometimes, part of the medium frequency (MF) band (300–3000 kHz) is included.


  • https://en.wikipedia.org/wiki/Medium_wave - the part of the medium frequency (MF) radio band used mainly for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz, using channels spaced every 9 kHz, and in North America an extended MW broadcast band goes from 535 kHz to 1705 kHz, using 10 kHz spaced channels.


Radio waves in this band can be reflected or refracted from a layer of electrically charged atoms in the atmosphere called the ionosphere. Therefore short waves directed at an angle into the sky can be reflected back to Earth at great distances, beyond the horizon. This is called skywave or skip propagation. Thus shortwave radio can be used for very long distance communication, in contrast to radio waves of higher frequency which travel in straight lines (line-of-sight propagation) and are limited by the visual horizon, about 40 miles. Shortwave radio is used for broadcasting of voice and music to shortwave listeners over very large areas; sometimes entire continents or beyond. It is also used for military over-the-horizon radar, diplomatic communication, and two-way international communication by amateur radio enthusiasts for hobby, educational and emergency purposes.





  • https://en.wikipedia.org/wiki/Microwave - with wavelengths ranging from one meter to one millimeter; with frequencies between 300 MHz (100 cm) and 300 GHz (0.1 cm). This broad definition includes both UHF and EHF (millimeter waves), and various sources use different boundaries. In all cases, microwave includes the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum, with RF engineering often restricting the range between 1 and 100 GHz (300 and 3 mm).

The prefix micro- in microwave is not meant to suggest a wavelength in the micrometer range. It indicates that microwaves are "small", compared to waves used in typical radio broadcasting, in that they have shorter wavelengths. The boundaries between far infrared, terahertz radiation, microwaves, and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study.


  • http://www.sigidwiki.com/wiki/Signal_Identification_Guide - wiki intended to help identify radio signals through example sounds and waterfall images. Most signals are received and recorded using a software defined radio such as the RTL-SDR, Airspy, SDRPlay, HackRF, BladeRF, Funcube Dongle, USRP or others. [1]

Broadcasting









AM

AM radio ranges from 535 to 1705 kilohertz, stations are possible every 10 kHz.

FM

FM radio ranges in a higher spectrum from 88 to 108 megahertz, stations are possible every 200 kHz.

Radio stations


  • RadioReference.com - Scanner Frequencies and Radio Frequency Reference
    • http://wiki.radioreference.com/index.php/Main_Page - RadioReference.com is the world's largest radio communications data provider, featuring a complete frequency database, trunked radio system information, and FCC license data. RadioReference is also the largest broadcaster of public safety live audio communications feeds, hosting thousands of live audio broadcasts of Police, Fire, EMS, Railroad, and aircraft communications.
  • HFUnderground.com, aka the HFU. This site is dedicated to documenting longwave, mediumwave, and shortwave stations, including broadcasters, utility/military stations, pirate radio and spy numbers stations.


  • OTRR Library is to provide broad and free access to mid-20th century radio broadcasting as a critical component of cultural history and also as a remarkably absorbing and exciting hobby, with the hope of keeping our own fascination alive through future generations of listeners... and budding researchers. Premise: the more people we expose to this great listening and learning experience, the better we preserve interest in these recordings, the individuals and the times that created them, and the recordings themselves for posterity.


  • Public Radio International (PRI) is a global non-profit media company focused on the intersection of journalism and engagement to effect positive change in people’s lives. We create a more informed, empathetic and connected world by sharing powerful stories, encouraging exploration, connecting people and cultures, and creating opportunities to help people take informed action on stories that inspire them. Its mission is to serve audiences as a distinctive content source for information, insights and cultural experiences essential to living in our diverse, interconnected world. Founded in 1983, PRI audio, text and visual content is currently consumed by almost 19 million people each month.
  • Public Radio Exchange (PRX) is an online marketplace for distribution, review, and licensing of public radio programming. PRX is also a growing social network and community of listeners, producers, and stations collaborating to reshape public radio.


  • Guerrilla Radio - How some inmates hack, rewire, and retool their radios to create walkie-talkies. [3]


BBC

NPR

HAM

  • https://en.wikipedia.org/wiki/Amateur_radio - also called ham radio, describes the use of radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communication. The term "amateur" is used to specify "a duly authorised person interested in radioelectric practice with a purely personal aim and without pecuniary interest;" (either direct monetary or other similar reward) and to differentiate it from commercial broadcasting, public safety (such as police and fire), or professional two-way radio services (such as maritime, aviation, taxis, etc.).

The amateur radio service (amateur service and amateur-satellite service) is established by the International Telecommunication Union (ITU) through the International Telecommunication Regulations. National governments regulate technical and operational characteristics of transmissions and issue individual stations licenses with an identifying call sign. Prospective amateur operators are tested for their understanding of key concepts in electronics and the host government's radio regulations. Radio amateurs use a variety of voice, text, image, and data communications modes and have access to frequency allocations throughout the RF spectrum to enable communication across a city, region, country, continent, the world, or even into space.





Mobile phone






4G

5G

Radio control

  • https://en.wikipedia.org/wiki/Radio_control - the use of radio signals to remotely control a device. Radio control is used for control of model vehicles from a hand-held radio transmitter. Industrial, military, and scientific research organizations make use of radio-controlled vehicles as well.



  • OpenSesame is a device that can wirelessly open virtually any fixed-code garage door in seconds, exploiting a new attack I've discovered on wireless fixed-pin devices. Using a child's toy from Mattel.

Data

  • https://en.wikipedia.org/wiki/Datacasting - the broadcasting of data over a wide area via radio waves. It most often refers to supplemental information sent by television stations along with digital television, but may also be applied to digital signals on analog TV or radio. It generally does not apply to data which is inherent to the medium, such as PSIP data which defines virtual channels for DTV or direct broadcast satellite systems; or to things like cable modem or satellite modem, which use a completely separate channel for data.



Software-defined radio

Hardware



  • Myriad RF is a family of open source hardware and software projects for wireless communications, and a community that is working to make wireless innovation accessible to as many people as possible.




RTL chipset

  • http://sdr.osmocom.org/trac/wiki/rtl-sdr - RTL-SDR is a set of tools that enables DVB-T USB dongles based on the Realtek RTL2832U chipset to be used as cheap software defined radios, given that the chip allows transferring raw I/Q samples from the tuner straight to the host device.

The frequency range of the RTL2832U / E4000 is generally around 64MHZ to 1700MHz with a gap around 1100MHz to 1250MHz. The RTL2832U / R820T frequency range is 24MHZ to roughly 1850MHz with no gaps (found yet), and no DC offset spike.

RTL dongles have 2.4 MHz of useful bandwidth.





Software



running the "volk_profile" gnuradio utility will detect and enable processor specific optimisations and will in many cases give a significant performance boost.


  • LuaRadio is a lightweight, embeddable flow graph signal processing framework for software-defined radio. It provides a suite of source, sink, and processing blocks, with a simple API for defining flow graphs, running flow graphs, creating blocks, and creating data types. [13]


  • FreeDV - a Digital Voice mode for HF radio. You can run FreeDV using a free GUI application for Windows, Linux and OSX that allows any SSB radio to be used for low bit rate digital voice.



Other

  • Identification Guide - wiki intended to help identify radio signals through example sounds and waterfall images. Most signals are received and recorded using a software defined radio such as the RTL-SDR, Airspy, SDRPlay, HackRF, BladeRF, Funcube Dongle, USRP or others.



Telephony

  • http://openbts.org/
    • - OpenBTS is a Unix application that uses a software radio to present a GSM air interface to standard 2G GSM handset and uses a SIP softswitch or PBX to connect calls. (You might even say that OpenBTS is a simplified form of IMS that works with 2G feature-phone handsets.) The combination of the global-standard GSM air interface with low-cost VoIP backhaul forms the basis of a new type of cellular network that can be deployed and operated at substantially lower cost than existing technologies in many applications, including rural cellular deployments and private cellular networks in remote areas.


Web SDR

Podcasts




RFID

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