the channel spacing currently used in europe for aircraft vhf voice communication is
Airband
4465419
Airband Airband or aircraft band is the name for a group of frequencies in the VHF radio spectrum allocated to radio communication in civil aviation, sometimes also referred to as "VHF", or phonetically as ""Victor"". Different sections of the band are used for radionavigational aids and air traffic control. In most countries a license to operate airband equipment is required and the operator is tested on competency in procedures, language and the use of the phonetic alphabet. The VHF airband uses the frequencies between 108 and 137 MHz. The lowest 10 MHz of the band, from 108–117.95 MHz, is split
Airband
21414
system works on the airband of 118.000 MHz to 136.975 MHz. Each channel is spaced from the adjacent ones by 8.33 kHz in Europe, 25 kHz elsewhere. VHF is also used for line of sight communication such as aircraft-to-aircraft and aircraft-to-ATC. Amplitude modulation (AM) is used, and the conversation is performed in simplex mode. Aircraft communication can also take place using HF (especially for trans-oceanic flights) or satellite communication. Air navigation is the determination of position and direction on or above the surface of the Earth. Avionics can use satellite navigation systems (such as GPS and WAAS), INS( inertial navigation
Avionics
5611508
ACARS In aviation, ACARS (; an acronym for aircraft communications addressing and reporting system) is a digital datalink system for transmission of short messages between aircraft and ground stations via airband radio or satellite. The protocol was designed by ARINC and deployed in 1978, using the Telex format. More ACARS radio stations were added subsequently by SITA. Prior to the introduction of datalink in aviation, all communication between the aircraft and ground personnel was performed by the flight crew using voice communication, using either VHF or HF voice radios. In many cases, the voice-relayed information involved dedicated radio operators and
ACARS
3075722
communications systems. Even within the allocation still dedicated to television, TV-band devices use channels without local broadcasters. The Apex band in the United States was a pre-WWII allocation for VHF audio broadcasting; it was made obsolete after the introduction of FM broadcasting. Airband refers to VHF frequencies 118 to 137 MHz, used for navigation and voice communication with aircraft. Trans-oceanic aircraft also carry HF radio and satellite transceivers. The greatest incentive for development of radio was the need to communicate with ships out of visual range of shore. From the very early days of radio, large oceangoing vessels carried powerful
Radio spectrum
4465419
Airband Airband or aircraft band is the name for a group of frequencies in the VHF radio spectrum allocated to radio communication in civil aviation, sometimes also referred to as "VHF", or phonetically as ""Victor"". Different sections of the band are used for radionavigational aids and air traffic control. In most countries a license to operate airband equipment is required and the operator is tested on competency in procedures, language and the use of the phonetic alphabet. The VHF airband uses the frequencies between 108 and 137 MHz. The lowest 10 MHz of the band, from 108–117.95 MHz, is split
Airband
780157
and interference (RFI) from electrical equipment is less of a problem in the band than at lower frequencies. The VHF band is the first band at which efficient transmitting antennas are small enough that they can be mounted on vehicles and portable devices, so the band is used for two-way land mobile radio systems, such as walkie-talkies, and two way radio communication with aircraft (Airband) and ships (marine radio). Occasionally, when conditions are right, VHF waves can travel long distances by tropospheric ducting due to refraction by temperature gradients in the atmosphere. For analog TV, VHF transmission range is a
Very high frequency
4465426
scheme, the largest bandwidth of an airband channel is limited to 8.33 kHz, so the highest possible audio frequency is 4.166 kHz. In the 25 kHz channel spacing scheme, an upper audio frequency of 12.5 kHz would be theoretically possible. However, most airband voice transmissions never actually reach these limits. Usually, the whole transmission is contained within a 6 kHz to 8 kHz bandwidth, corresponding to an upper audio frequency of 3 kHz to 4 kHz. This frequency, while low compared to the top of the human hearing range, is sufficient to convey speech. Different aircraft, control towers and other
Airband
4465422
243.0 MHz. Radio aeronautical navigation aids (navaids) use other frequencies. Non-directional beacons (NDB)s operate on low frequency and medium frequency bands between 190–415 kHz and 510–535 kHz. The instrument landing system (ILS) glide path operates in the UHF frequency range of 329.3–335.0 MHz with marker beacons at 75 MHZ. Distance measuring equipment (DME) also uses UHF from 962–1150 MHz. Channel spacing for voice communication on the airband was originally 200 kHz until 1947, providing 70 channels from 118 to 132 MHz. Some radios of that time provided receive-only coverage below 118 MHz for a total of 90 channels. From 1947–1958
Airband
19242300
10 Watts. This equipment provided for 125 radio channels at 50 kHz channel spacing. It was usually used with a 2-metre antenna. Was present in almost all German tanks and some other vehicles. Was the standard kit for tank-to-tank communication within platoons and companies. Range was approx 2–3 km when using AM voice and 3–4 km when using CW. FuG 6: A high-band HF/low-band VHF transceiver. It operated in the 27,000 to 33,3000 kHz (27-33.3 MHz) frequency range with a transmit power of 20 Watts. It was usually used with a 2-metre antenna. It was used by armoured observation posts.
Wireless Communications of the German Army in World War II
4465424
of 2012. The emergency communication channel 121.5 MHz is the only channel that retains 100 kHz channel spacing in the US; there are no channel allocations between 121.4 and 121.5 or between 121.5 and 121.6 Aircraft communications radio operations worldwide use amplitude modulation, predominantly A3E double sideband with full carrier on VHF and UHF, and J3E single sideband with suppressed carrier on HF. Besides being simple, power-efficient and compatible with legacy equipment, AM and SSB permit stronger stations to override weaker or interfering stations. Additionally, this method does not suffer from the capture effect found in FM. Even if a
Airband
518878
25 kHz channel spacing, for a total of 69 channels. In some countries, LPD devices may only be used with an integral and non-removable antenna with a maximum legal power output of 10 mW. Voice communication in the LPD band was introduced to reduce the burden on the eight (now sixteen) PMR446 channels over shorter ranges (less than 1 km) . In some EU countries voice is not allowed over LPD. LPD is also used by wireless instruments and digital devices such as car keylocks. ITU Region 1 (Europe) United Kingdom In the UK, LPD433 equipment that meets the respective
LPD433
11471474
themselves to the same channel in a different district by using sub-bands. Aviation voice radios use Aircraft band VHF AM. AM is used so that multiple stations on the same channel can be received. (Use of FM would result in stronger stations blocking out reception of weaker stations due to FM's capture effect). Aircraft fly high enough that their transmitters can be received hundreds of miles away, even though they are using VHF. Marine voice radios can use single sideband voice (SSB) in the shortwave High Frequency (HF—3 MHz to 30 MHz) radio spectrum for very long ranges or Marine
Radio
2756981
region, the ship MMSI prefixed with "9". The requirement to use ATIS in Europe, and which VHF channels may be used, are strongly regulated, most recently by the Basel agreements. Half-duplex channels here are listed with the A and B frequencies the same. The frequencies, channels, and some of their purposes are governed by the ITU. For an authoritative list see. The original allocation of channels consisted of only channels 1 to 28 with 50 kHz spacing between channels, and the second frequency for full-duplex operation 4.6 MHz higher. Improvements in radio technology later meant that the channel spacing could
Marine VHF radio
11658967
certified for Part 25 aircraft. Universal offers a Terrain Awareness and Warning System (TAWS) with a 3D perspective mode. Universal offers Flat Panel Integrated Displays. Universal offers the 1 MCU UniLink CMU (Communication Management Unit) with or without a built-in VDR (VHF Data Radio). The UniLink CMU is capable of operating in 25 kHz and 8.333 kHz channel spacing environments and operating as part of the ACARS data network. Universal Avionics Universal Avionics Systems Corporation is an international company headquartered in Tucson, Arizona in the United States. It primarily focuses on Flight Management Systems (FMS) and cockpit instrument displays for
Universal Avionics
4465423
the spacing became 100 kHz; from 1954 split once again to 50 kHz and the upper limit extended to 135.95 MHz (360 channels), and then to 25 kHz in 1972 to provide 720 usable channels. On 1 January 1990 the frequencies between 136.000 and 136.975 MHz were added, resulting in 760 channels. Increasing air traffic congestion has led to further subdivision into narrow-band 8.33 kHz channels in the ICAO European region; all aircraft flying are required to have communication equipment for this channel spacing. Outside of Europe, 8.33 kHz channels are permitted in many countries but not widely used as
Airband
3706972
band). This required a reassignment of the VHF channels to the plan currently in use. Notes: Note: Basically, the frequency spacing for each channel is 6 MHz as the countries above, except between channels 7 and 8 (which overlap). Channels A through H are indicated in many European TVs as Channels 13-20. Channels B through H2 are identical to Channel E4 and up. Channel A video carrier is the same as Channel E2 video carrier and thus it used to be common that the audio from a distant TV station on channel E2 received via Sporadic E interferes with Channel
Television channel frequencies
12244649
channel number associated, etc. It is possible that the older 44/33 channel list is obsolete, as no radios are produced that offer the offset frequency plan. However, it is probable that both channel plans are currently in use in India, and this will likely continue into the foreseeable future. The 27-channel plan offers wider channel spacing to reduce interference, compatibility with internationally agreed channel plans, and provision for five dedicated and one shared remote control (R/C) for toys, aircraft, boats, telemetry, paging and other non-voice communications. Channels 1–27 are the same as the channels 1–27 for the USA, Australian, and
Citizens band radio in India
10569939
Channel 16 VHF Channel 16 VHF (156.8 MHz) is a marine VHF radio frequency designated as an international distress frequency. Primarily intended for distress, urgency and safety priority calls, the frequency may also carry routine calls used to establish communication before switching to another working channel. The International Telecommunications Union (ITU) has established VHF channel 16 (156.8 MHz) as a distress, safety and calling channel, and it is monitored 24 hours a day by many coast guards around the world. Radio watchkeeping regulations advise all sea bound vessels to monitor channel 16 VHF when sailing, except when communicating on other
Channel 16 VHF
8991539
Band III Band III is the name of the range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum from 174 to 240 megahertz (MHz). It is primarily used for radio and television broadcasting. It is also called high-band VHF, in contrast to Bands I and II. The band is subdivided into seven channels for television broadcasting, each occupying 6 MHz. European Band III allocations vary from country to country, with channel widths of 7 or 8 MHz. The standard channel allocations for European countries that use System B with 7 MHz channel spacing are
Band III
1397816
GPS Receiver (PLGR) devices providing radio level situational awareness capability. In 1992, the U.S. Air Force awarded a contract to replace the AN/ARC-188 for communications between Air Force aircraft and Army units. SINCGARS Single Channel Ground and Airborne Radio System (SINCGARS) is a Combat Net Radio (CNR) currently used by U.S. and allied military forces. The radios, which handle voice and data communications, are designed to be reliable, secure, and easily maintained. Vehicle-mount, backpack, airborne, and handheld form factors are available. SINCGARS uses 25 kHz channels in the very high frequency (VHF) FM band, from 30.000 to 87.975 megahertz (MHz).
SINCGARS
1397801
the French MRCC on 1696 kHz and 2677 kHz, Stornoway Coastguard on 1743 kHz, the US Coastguard on 2670 kHz and Madeira on 2843 kHz. RN Northwood in England broadcasts Weather Fax data on 2618.5 kHz. Non-directional navigational radio beacons (NDBs) for maritime and aircraft navigation occupy a band from 190 to 435 kHz, which overlaps from the LF into the bottom part of the MF band. 2182 kHz is the international calling and distress frequency for SSB maritime voice communication (radiotelephony). It is analogous to Channel 16 on the marine VHF band. 500 kHz was for many years the
Medium frequency
7438275
controls are present. The C-38 also has controls for the R-4A homing receiver. A common AN/ARC-5 transmitter control box C-30A/ARC-5 has controls for selecting the MF/HF transmitter or the VHF transmitter, and a switch to select the channel for both the VHF transmitter and receiver. Mode controls are normally set for voice and covered. The typical AN/ARC-5 three-receiver, two-transmitter installation reflects system capabilities that are quite sophisticated compared to the earlier systems, allowing VHF homing, four channel VHF-AM communications, and one channel MF/HF-AM communications. All unnecessary controls have been eliminated to simplify operation of this more capable system. Aircraft Radio
AN/ARC-5
5611518
this role to suit its needs. ACARS messages may be sent using a choice of communication methods, such as VHF or HF, either direct to ground or via satellite, using minimum-shift keying (MSK) modulation. ACARS can send messages over VHF if a VHF ground station network exists in the current area of the aircraft. VHF communication is line-of-sight propagation and the typical range is up to 200 nautical miles at high altitudes. Where VHF is absent, an HF network or satellite communication may be used if available. Satellite coverage may be limited at high latitudes (trans-polar flights). In the wake
ACARS
4465421
ballooning air-to-ground, flight test and national aviation authority use. A typical transmission range of an aircraft flying at cruise altitude (), is about in good weather conditions. Aeronautical voice communication is also conducted in other frequency bands, including satellite voice on Inmarsat or Iridium, and high frequency voice. Usually these other frequency bands are only used in oceanic and remote areas, though they work over wider areas or even globally. Military aircraft also use a dedicated UHF-AM band from 225.0–399.95 MHz for air-to-air and air-to-ground, including air traffic control communication. This band has a designated emergency and guard channel of
Airband
12559942
Mode 2 Physical Layer specifies the use in a 25 kHz wide VHF channel of a modulation scheme called Differential 8-Phase-shift keying with a symbol rate of 10,500 symbols per second. The raw (uncoded) physical layer bit rate is thus 31.5 kilobit/second. This required the implementation of VHF digital radios. The ICAO standard for VDL Mode 3 defines a protocol providing aircraft with both data and digitized voice communications that was defined by the US FAA with support from Mitre. The digitized voice support made the Mode 3 protocol much more complex than VDL Mode 2. The data and digitized
VHF Data Link
2756977
on the set or microphone which turns the transmitter on and the receiver off. Some channels, however, are "full duplex" transmission channels where communication can take place in both directions simultaneously when the equipment on both ends allow it. Each full-duplex channel has two frequency assignments. Duplex channels can be used to place calls over the public telephone network for a fee via a marine operator. When full-duplex is used, the call is similar to one using a mobile phone or landline. When half-duplex is used, voice is only carried one way at a time and the party on the
Marine VHF radio
4236938
One-way voice link A one-way voice link (OWVL) is typically a radio based communication method used by spy networks to communicate with agents in the field typically (but not exclusively) using shortwave radio frequencies. Shortwave frequencies were and are generally highly preferred for their long range, as a communications link of 1200 km is easily possible. VHF and UHF frequencies can be used for one-way voice circuits, but are generally not preferred as their range is at best 300 km (on flat terrain). Since the 1970s infrared point-to-point communication systems have been used that offer OWVLs, but the number of
One-way voice link
4236941
really use it during this conflict. One-way voice link A one-way voice link (OWVL) is typically a radio based communication method used by spy networks to communicate with agents in the field typically (but not exclusively) using shortwave radio frequencies. Shortwave frequencies were and are generally highly preferred for their long range, as a communications link of 1200 km is easily possible. VHF and UHF frequencies can be used for one-way voice circuits, but are generally not preferred as their range is at best 300 km (on flat terrain). Since the 1970s infrared point-to-point communication systems have been used that
One-way voice link
4465420
into 200 narrow-band channels of 50 kHz. These are reserved for navigational aids such as VOR beacons, and precision approach systems such as ILS localizers. , most countries divide the upper 19 MHz into 760 channels for amplitude modulation voice transmissions, on frequencies from 118–136.975 MHz, in steps of 25 kHz. In Europe, it is becoming common to further divide those channels into three (8.33 kHz channel spacing), potentially permitting 2,280 channels. Some channels between 123.100 and 135.950 are available in the US to other users such as government agencies, commercial company advisory, search and rescue, military aircraft, glider and
Airband
1402
the earliest modulation method used to transmit voice by radio. It was developed during the first quarter of the 20th century beginning with Landell de Moura and Reginald Fessenden's radiotelephone experiments in 1900. It remains in use today in many forms of communication; for example it is used in portable two-way radios, VHF aircraft radio, citizens band radio, and in computer modems in the form of QAM. "AM" is often used to refer to mediumwave AM radio broadcasting. In electronics and telecommunications, modulation means varying some aspect of a continuous wave carrier signal with an information-bearing modulation waveform, such as
Amplitude modulation
20295756
Communication, navigation and surveillance Communication, navigation and surveillance (CNS) are the main functions that form the infrastructure for air traffic management, <ref name="CNS/ATM"></ref> and ensure that air traffic is safe and efficient. The CNS has the following three main functions. Communication, i.e. aviation communication, refers to radio communication between two or more aircraft, or the exchange of data or verbal information between aircraft and air traffic control. For continental airspace, VHF (civil) and UHF (military) systems are used whereas for oceanic areas, high frequency systems and SATCOMs are used. Navigation, i.e. air navigation, refers to the process of planning, recording,
Communication, navigation and surveillance
3706973
A video and vice versa. In it is very early days DFF made some test transmissions using the D/K standard (6.5 MHz audio) before reverting (around 1957) to System B/G (5.5 MHz audio) but using some unique frequencies # . From 1960 onwards (West) European standard channels were adopted. Note VHF analog TV ceased in New Zealand on the 1st of December 2013. See North American broadcast television frequencies for frequencies used in North America. Note: Channels 13-62 are used for analog and digital TV broadcasting. Frequency spacing for each channel in Japan is the same as in the countries
Television channel frequencies
16354746
5 watts. The channel plan follows channels 1–27 from the standard 40 channel CB plan originally adopted by the United States (and most other countries worldwide). Channel 1 is 26.965 and channel 27 is 27.275 MHz. Use of frequencies below 26.965 or above 27.275 is not permitted in India. Multi-norm mobile CB radios are now being shipped with the 27 channel India CB frequency plan programmed in them. Two frequency bands available: VHF-FM (142–143 MHz VHF CB) and UHF-FM (476–477 MHz UHF CB). Indonesia allows 40 channels from 476.425 MHz to 477.400 MHz at 25 kHz channel spacing. It is
Personal radio service
5288627
nm with approximately a 0.8 nm channel spacing. For practical purposes, the grid has been extended to cover 186 THz to 201 THz and subdivided to provide 50 GHz and 25 GHz spaced grids. Frequency grid A frequency grid is a table of all the central frequencies (and corresponding wavelengths) of channels allowed in a communications system. The most common frequency grid used for fiber-optic communication is that used for channel spacing in Dense Wavelength Division Multiplexing (DWDM) at wavelengths around 1550 nm and defined by ITU-T G.694.1. The grid is defined relative to 193.1 THz and extends from 191.7
Frequency grid
5578542
aircraft. The IAR-99 is also equipped with video and debriefing systems. The communication systems include VHF and UHF communications, voice-activated intercom and an IFF transponder. The flight systems include a VOR/ILS, linked VHF omnidirectional antenna radio ranger linked to the instrument landing system. Other navigation tools include distance measuring equipment (DME), an automatic direction finder (ADF), a Northrop Grumman inertial navigation system and a Trimble GPS system. One of the best features of the aircraft avionics is a virtual training system which allows, based on a data link system, inflight simulations of firing and air combat capabilities using two or
IAR 99
1780079
change which frequencies work best. Single-sideband (SSB) is used because the short wave bands are crowded with many users, and SSB permits a single voice channel to use a narrower range of radio frequencies (bandwidth), about 3.5 kHz. In comparison, AM radio uses about 8 kHz, and narrowband (voice or communication-quality) FM uses 9 kHz. Marine radiotelephony first became common in the 1930s, and was used extensively for communications to ships and aircraft over water. In that time, most long-range aircraft had long-wire antennas that would be let out during a call, and reeled-in afterward. Marine radiotelephony originally used AM
Radiotelephone
11961529
the airport's listed frequency ( 121.725 or 135.075 ). The system is activated with four “key clicks” on the VHF radio to contact the appropriate ATC facility or six “key strokes” to contact the FSS. There is a timer on the modem connection. If no voice is heard for a preset interval, the system disconnects. The VHF transceiver is very low power, 2 - 5 watts, which sometimes limits access. The GCO system is intended to be used only on the ground. GCO availability is noted in the text portion of the airport diagram. Ground communication outlet Ground Communications Outlets
Ground communication outlet
7438257
AN/ARC-5 The AN/ARC-5 Command Radio Set is a series of radio receivers, transmitters, and accessories carried aboard U.S. Navy aircraft during World War II and for some years afterward. It is described as ""a complete multi-channel radio transmitting and receiving set providing communication and navigation facilities for aircraft. The LF-MF-HF components are designed to transmit and receive voice, tone-modulated, and continuous wave (cw) signals."" Its flexible design provided AM radiotelephone voice communication and MCW and CW Morse code modes, all of which are typical capabilities in other Navy aircraft communication sets of the period. It was an improvement of the
AN/ARC-5
4539556
of models. The transmitter radio broadcasts using AM or FM using PPM or PCM. Each aircraft needs a way to determine which transmitter to receive communications from, so a specific channel within the frequency band is used for each aircraft (except for 2.4 GHz band, and amateur radio-only 70cm systems; which use spread spectrum modulation, described below). Most radio control systems - traditionally on low-VHF-band frequencies, before the 21st century - have traditionally used crystals to set the operating channel in the receiver and transmitter. It is important that each aircraft uses a different channel, otherwise interference could result. For
Radio-controlled aircraft
16442126
1971, only about 170 full-service UHF stations operated. In the United States, the UHF stations gained a reputation for local ownership, nonprofessional operations, small audiences and weaker signal propagation. While UHF-TV has been available to American TV broadcasters since 1952, affiliates of the four major American TV networks (NBC, CBS, ABC, and DuMont) continued to transmit primarily on VHF wherever they were available. With the availability of the twelve VHF television channels limited by FCC spacing rules to avoid co-channel and adjacent channel interference between TV stations in the same or nearby cities, all available VHF-TV allocations were already in
UHF television broadcasting
16354739
as low as 25 MHz and as high as 30 MHz) and the 43 MHz area (as 43 MHz CB equipment is often modified to cover down to 34 MHz and up to 47 MHz, using 12.5 kHz steps). There is evidence of these frequencies being used outside of Italy for illegal "CB-like" operations. Italian 43 MHz "VHF CB" or "43 MHz CB" allocation. 24 channels, FM mode, 12.5 kHz channel spacing. Each channel has a "recommended use" associated with it. Portable handheld (walkie-talkie), in-vehicle mobile and base station transceivers are available for this band. Channels are numbered in straight
Personal radio service
9116249
Controller–pilot data link communications Controller–pilot data link communications (CPDLC), also referred to as controller pilot data link (CPDL), is a method by which air traffic controllers can communicate with pilots over a datalink system. The standard method of communication between an air traffic controller and a pilot is voice radio, using either VHF bands for line-of-sight communication or HF bands for long-distance communication (such as that provided by Shanwick Oceanic Control). One of the major problems with voice radio communications used in this manner is that all pilots being handled by a particular controller are tuned to the same frequency.
Controller–pilot data link communications
8517039
systems. It is also equipped with six passenger lifts, one freight lift, three escalators and a baggage handling system. Three out of the six passenger boarding bridges can handle modern Boeing 747-400 aircraft. There is sufficient space for ten aircraft to anchor, and at a rate of 8 minutes per plane, aircraft of any size and make can touch down or take off to any destination abroad. MAGS (Mandalay Airport Ground Services) provides both passenger and cargo aircraft ground services. Systems incorporated into the airport include VHF and HF SSB transmitters and receivers, a voice communication control system, an automatic
Mandalay International Airport
1780070
and receive on two separate channels, which both wastes bandwidth and presents some technical challenges. It is, however, the most comfortable method of voice communication for users, and it is currently used in cell phones and was used in the former IMTS. The most common method of working for radiotelephones is half-duplex, operation, which allows one person to talk and the other to listen alternately. If a single channel is used, both ends take turns to transmit on it. Dual-frequency working splits the communication into two separate channels, but only one is used to transmit at a time. The user
Radiotelephone
4532866
to give the Hampton Roads area a third VHF station; WVEC-TV moved there from channel 15 shortly afterward. To alleviate concerns about short-spacing, the channel 13 allocation for New Bern was moved to channel 12. Almost immediately, WRVA-TV in Richmond, Virginia (now WWBT) raised concerns of its own about short-spacing. All objections were eventually overcome by 1961, and the station went on the air on September 7, 1963, as WNBE-TV (for "New B Ern"). The call letters were changed to the current WCTI-TV in 1970. The station has been an ABC affiliate since its inception. When it signed on, the
WCTI-TV
7466550
in the control area and uses VHF voice to provide instructions to the flight crews to ensure separation. Because the position of the aircraft is updated frequently and VHF voice contact timely, separation standards (the distance by which one aircraft must be separated from another) are less. This is because the air traffic controller can recognize problems and issue corrective directions to multiple airplanes in a timely fashion. Separation standards are what determine the number of airplanes which can occupy a certain volume of airspace. Procedural control is used in areas (oceanic or land) which do not have radar. The
Future Air Navigation System
13647861
CCIR System M CCIR (or FCC) System M, sometimes called 525 line, is the analog broadcast television system used in the United States since July 1, 1941, and also in most of the Americas and Caribbean, South Korea, and Taiwan. Japan uses System J, which is nearly identical to System M. The systems were given their letter designations in the ITU identification scheme adopted in Stockholm in 1961. Both System M and System J display 525 lines of video at 30 frames per second using 6 MHz spacing between channel numbers, and is used for both VHF and UHF channels.
CCIR System M
16825775
low band (Band I) between 54 and 88 MHz, containing channels 2 through 6, and VHF high band (Band III) between 174 and 216 MHz, containing channels 7 through 13. The wide spacing between these frequency bands is responsible for the complicated design of rooftop TV antennas. The UHF band has higher noise and greater attenuation, so higher gain antennas are often required for UHF. The VHF band plan was modified several times before 1948. The last of these changes was the deletion of channel 1, originally intended as a community channel. This allocation of the spectrum was given to
Pan-American television frequencies
11471475
VHF radio / "narrowband FM" in the VHF spectrum for much shorter ranges. Narrowband FM sacrifices fidelity to make more channels available within the radio spectrum, by using a smaller range of radio frequencies, usually with five kHz of deviation, versus the 75 kHz used by commercial FM broadcasts, and 25 kHz used for TV sound. Government, police, fire and commercial voice services also use narrowband FM on special frequencies. Early police radios used AM receivers to receive one-way dispatches. Civil and military HF (high frequency) voice services use shortwave radio to contact ships at sea, aircraft and isolated settlements.
Radio
5288626
Frequency grid A frequency grid is a table of all the central frequencies (and corresponding wavelengths) of channels allowed in a communications system. The most common frequency grid used for fiber-optic communication is that used for channel spacing in Dense Wavelength Division Multiplexing (DWDM) at wavelengths around 1550 nm and defined by ITU-T G.694.1. The grid is defined relative to 193.1 THz and extends from 191.7 THz to 196.1 THz with 100 GHz spacing. While defined in frequency, the grid is often expressed in terms of wavelength, in which case it covers the wavelength range of 1528.77 nm to 1563.86
Frequency grid
4303897
as an intermediate frequency within television receivers became commonplace after UHF reception became an option in 1953. Channel 1's signal on this frequency (over the air, or on analogue cable) could create interference internally within TV's. Most cable systems use frequencies below 54 MHz (VHF TV 2) for communication back to the cable provider from cable modems and digital apparatus, so any "Cable 1" channel needs to avoid operation on the original VHF Channel 1 frequencies from the pre-1948 bandplans. As such, "cable 1" is not related to the original 44–50 MHz VHF channel except in name. It operates always
Channel 1 (North American TV)
2246921
a VHF radio composite signal including the navigation signal, station's identifier and voice, if so equipped. The navigation signal allows the airborne receiving equipment to determine a bearing from the station to the aircraft (direction from the VOR station in relation to Magnetic North). The station's identifier is typically a three-letter string in Morse code. The voice signal, if used, is usually the station name, in-flight recorded advisories, or live flight service broadcasts. At some locations, this voice signal is a continuous recorded broadcast of Hazardous Inflight Weather Advisory Service or HIWAS. Developed from earlier Visual Aural Radio Range (VAR)
VHF omnidirectional range
3075723
long-wave and medium-wave transmitters. High-frequency allocations are still designated for ships, although satellite systems have taken over some of the safety applications previously served by 500 kHz and other frequencies. 2182 kHz is a medium-wave frequency still used for marine emergency communication. Marine VHF radio is used in coastal waters and relatively short-range communication between vessels and to shore stations. Radios are channelized, with different channels used for different purposes; marine Channel 16 is used for calling and emergencies. Amateur radio frequency allocations vary around the world. Several bands are common for amateurs worldwide, usually in the HF part of
Radio spectrum
4925569
spacing on UHF CB was changed, allowing the band to expand from 40 channels to 80 channels. Due to data channels 22 and 23 occupying 25 kHz bandwidth, the expansion effectively allows the use of 77 channels, as channels 61, 62 and 63 are reserved. General chat channels are used in simplex mode, repeater channels must be used in duplex mode. If you are not using a repeater it is recommended to choose a "general chat" channel. Currently, older 40 channel radios may still use 25 kHz spacing after ACMA Review 25kHz will be allowed for the immediate future with
UHF CB
12996550
crew reported five trains of bombs burning in the river. Another crew saw a string of bombs north of the course near Koromo. While radio discipline appeared to be good overall, communication with the weather ship on the VHF channel appeared to leave room for improvement. Only four sightings were made of enemy aircraft and no heavy anti-aircraft fire was experienced and meager, inaccurate automatic weapon fire at lower altitude was observed. But with three BGs, totaling 94 aircraft, in the area and apparently scheduled fairly close together, mistakes were made. The 330th BG lost one aircraft. This was the
330th Bombardment Group (VH)
19787019
as well as a concise manual in German and a CE mark. The user is not permitted to modify the device. The Federal Network Agency has laid out strict parameters for modulation, bandwidth and channel spacing in its ordinance. In practice, relatively high prices for Freenet devices have kept away domestic users from the service. Oftentimes, modified amateur radio transceivers are used, violating the restrictions for the Freenet service. With the maximum permitted ERP of 500 mW, a range of 1 km can be assumed. Due to the lower frequencies in the VHF band, signal attenuation from objects, such as
Freenet (radio)
11210687
North America, F2 is most likely to only affect VHF TV channel 2, in Europe and middle east channel E2 and E3 (and the now deprecated channel itA) and in eastern Europe channel R1. Television pictures propagated via F2 tend to suffer from characteristic ghosting and smearing. Picture degradation and signal strength attenuation increases with each subsequent F2 hop. F2 propagation The E layer of the ionosphere is not the only layer that can reflect VHF television signals. Less frequently, the higher F2 layer can also propagate VHF signals several thousand miles beyond their intended area of reception. Solar activity
F2 propagation
1397656
compatible with the SINCGARS frequency hopping mode. During the Vietnam War, the PRC-77 used the earlier TSEC/KY-38 NESTOR voice encryption system. Major components: Minor components - CES (Complete Equipment Schedule): AN/PRC-77 Portable Transceiver AN/PRC 77 Radio Set is a manpack, portable VHF FM combat-net radio transceiver manufactured by Associated Industries and used to provide short-range, two-way radiotelephone voice communication. In the Joint Electronics Type Designation System (JETDS), AN/PRC translates to "Army/Navy, Portable, Radio, Communication." The AN/PRC-77 entered service in 1968 during the Vietnam War as an upgrade to the earlier AN/PRC-25. It differs from its predecessor mainly in that its
AN/PRC-77 Portable Transceiver
2757081
alert by any means to land. Class A devices, used on commercial ships, have the ability to send distress, distress relay, all ships urgency, all ships safety, individual, group, geographic area and telephone alerts. Class D devices, used for most leisure vessels, can send distress, all ships urgency, all ships safety and individual on VHF channels 06, 08, 72 and 77. The latter is only required to have one antenna and is thus not required to watch Channel 70 when in use. For routine alerts, which are used to establish communication with another station on a working channel, the receiver
Digital selective calling
2307327
are scrambled and require a Sky Television H.264 set-top box such as MySky, which costs the price of a basic subscription plus addition MySky rental fee. TVNZ's functions are subject to "lifeline utility requirements" under NZ civil defence legislation. In practice, this status as a lifeline utility requires TVNZ to be able to function at least to a reduced level after an emergency, and to provide advice to civil defence authorities when requested. New Zealand uses PAL B (7 MHz channel spacing) on VHF, and PAL G (8 MHz channel spacing) on UHF. New Zealand has a near nationwide implementation
TVNZ
4431260
military airborne and air defense radars, however, operate in VHF, UHF, and microwave band, which have frequencies higher than the characteristic plasma frequency of ionosphere, therefore microwave can penetrate the ionosphere and communication between the ground and communication satellites demonstrates is possible. ("Some" frequencies can penetrate the ionosphere). Plasma surrounding an aircraft might be able to absorb incoming radiation, and therefore reduces signal reflection from the metal parts of the aircraft: the aircraft would then be effectively invisible to radar at long range due to weak signals received. A plasma might also be used to modify the reflected waves to
Plasma stealth
8382278
Aircraft Meteorological Data Relay Aircraft Meteorological Data Relay (AMDAR) is a program initiated by the World Meteorological Organization. AMDAR is used to collect meteorological data worldwide by using commercial aircraft. Data is collected by the aircraft navigation systems and the onboard standard temperature and static pressure probes. The data is then preprocessed before linking them down to the ground either via VHF communication (ACARS) or via satellite link ASDAR. A detailed description is given in the AMDAR Reference Manual (WMO-No 958) available from the World Meteorological Organization, Geneva, Switzerland. AMDAR transmissions are most commonly used in forecast models as a
Aircraft Meteorological Data Relay
17128676
AN/ARC-210 The ARC-210 is a family of radios for military aircraft that provides two-way, multi-mode voice and data communications over a 30 to 512+ MHz frequency range. It covers both Ultra High Frequency (UHF) and Very High Frequency (VHF) bands with AM, FM and SATCOM capabilities. The ARC-210 radio also includes embedded anti-jam waveforms, including Havequick and SINCGARS, and other data link and secure communications features, providing total battlefield interoperability and high-performance capabilities in the transfer of data, voice and imagery. It features a separate guard receiver for monitoring 121.5 and 243 MHz while simultaneously monitoring the active channel selected.
AN/ARC-210
5170097
guide missiles towards the pilot's visual target. An externally carried day/night laser designator targeting pod may be integrated with the avionics to guide laser-guided bombs (LGBs). An extra hardpoint may be added under the starboard air intake, opposite the cannon, for such pods. To reduce the numbers of targeting pods required, the aircraft's tactical data link can transmit target data to other aircraft not equipped with targeting pods. The communication systems comprise two VHF/UHF radios; the VHF radio has the capacity for data linking for communication with ground control centers, airborne early warning and control aircraft and combat aircraft with
CAC/PAC JF-17 Thunder
6323251
service, this technically is not a request for a DTx (distributed transmission system). The transmitters may not be synchronized and therefore could interfere with each other in certain narrow geographical areas. The affected locations are all currently unpopulated. The station's digital channel is multiplexed: Since 2016, KYES airs programming in high definition. KYES-TV shut down its analog signal, over VHF channel 5, on June 13, 2009, one day later. The station's digital signal relocated from its pre-transition VHF channel 6 to channel 5. KYES-TV KYES-TV, virtual channel 5 (VHF digital channel 7), is a MyNetworkTV-affiliated television station licensed to Anchorage,
KYES-TV
13551262
interface is defined by the following ETSI standards: The DMR standard operates within the existing 12.5 kHz channel spacing used in land mobile frequency bands globally, but achieves two voice channels through two-slot TDMA technology built around a 30 ms structure. The modulation is 4-state FSK, which creates four possible symbols over the air at a rate of 4,800 symbols/s, corresponding to 9,600 bit/s. After overhead, forward error correction, and splitting into two channels, there is 2,450 bit/s left for a single voice channel using DMR, compared to 4,400 bit/s using P25 and 64,000 bit/s with traditional telephone circuits. The
Digital mobile radio
20101096
late 1970s, the ARC-182s were manufactured by Rockwell Collins and are installed in a range of U.S. Navy, Marines and Coast Guard aircraft. Its frequency range includes the following bands: Channel spacing is 25 kHz in all bands. The transceiver weights about 10 lb (4.54 kg). Available accessories include remote controls, transmit power amplifiers, antennas, and ground support equipment. It has been largely replaced by the AN/ARC-210 series. AN/ARC-182 The AN/ARC-182 is a family of military aircraft radio transceivers designed for two-way, multi-mode voice communications over a 30 to 400 MHz frequency range. It covers both Ultra High Frequency (UHF)
AN/ARC-182
3682554
it suitable for all stages of advanced flight training and thus reducing the use of combat aircraft for training purposes. A modular avionics architecture is employed, allowing for new equipment and systems to be incorporated and increasing the type's growth potential. The M-346's glass cockpit is representative of the latest generation cockpit and is compatible with night vision goggles; it has three color LCD multifunctional displays, a head-up display, and an optional helmet-mounted display. A voice command system is also present, which is integrated with functions such as the navigation system. The communication systems include VHF/UHF transceivers, IFF transponder, and
Alenia Aermacchi M-346 Master
1397654
AN/PRC-77 Portable Transceiver AN/PRC 77 Radio Set is a manpack, portable VHF FM combat-net radio transceiver manufactured by Associated Industries and used to provide short-range, two-way radiotelephone voice communication. In the Joint Electronics Type Designation System (JETDS), AN/PRC translates to "Army/Navy, Portable, Radio, Communication." The AN/PRC-77 entered service in 1968 during the Vietnam War as an upgrade to the earlier AN/PRC-25. It differs from its predecessor mainly in that its final power amplifier stage is made up of solid state components and not vacuum tubes like the PRC-25. Also the PRC-77 has the ability to use voice encryption devices, while
AN/PRC-77 Portable Transceiver
1397814
SINCGARS Single Channel Ground and Airborne Radio System (SINCGARS) is a Combat Net Radio (CNR) currently used by U.S. and allied military forces. The radios, which handle voice and data communications, are designed to be reliable, secure, and easily maintained. Vehicle-mount, backpack, airborne, and handheld form factors are available. SINCGARS uses 25 kHz channels in the very high frequency (VHF) FM band, from 30.000 to 87.975 megahertz (MHz). It has single-frequency and frequency hopping modes. The frequency-hopping mode hops 111 times a second. The SINCGARS family has mostly replaced the Vietnam War-era synthesized single frequency radios (AN/PRC-77 and AN/VRC-12), although
SINCGARS
517772
Digital Signal 0 Digital Signal 0 (DS0) is a basic digital signaling rate of 64 kilobits per second (kbit/s), corresponding to the capacity of one analog voice-frequency-equivalent communication channel. The DS0 rate, and its equivalents E0 in the E-carrier system and T0 in the T-carrier system, form the basis for the digital multiplex transmission hierarchy in telecommunications systems used in North America, Europe, Japan, and the rest of the world, for both the early plesiochronous systems such as T-carrier and for modern synchronous systems such as SDH/SONET. The DS0 rate was introduced to carry a single digitized voice call. For
Digital Signal 0
3199196
transponder load. DME frequencies are paired to VHF omnidirectional range (VOR) frequencies and a DME interrogator is designed to automatically tune to the corresponding DME frequency when the associated VOR frequency is selected. An airplane’s DME interrogator uses frequencies from 1025 to 1150 MHz. DME transponders transmit on a channel in the 962 to 1213 MHz range and receive on a corresponding channel between 1025 and 1150 MHz. The band is divided into 126 channels for interrogation and 126 channels for reply. The interrogation and reply frequencies always differ by 63 MHz. The spacing of all channels is 1 MHz
Distance measuring equipment
13897367
truck, and consists of the following. AN/MRN-2 The AN/MRN-2 was a Radio Range set used by the Army Air Force during and after World War II, it replaced in part the SCR-277. The set is a ground mobile, two course, VHF aural Radio Range with station identification, periodic sector identification and simultaneous voice transmission. it is a crystal controlled set and operates in the frequency range of 100 to 156 Mc. for use in guiding aircraft equipped with VHF radio receivers, such as SCR-522, to a landing field, or for use along ferry routes. effective range is 100 Miles. The
AN/MRN-2
8382279
supplement to radiosonde data, to aid in the plotting of upper-air data between the standard radiosonde soundings at 00Z and 12Z. Aircraft Meteorological Data Relay Aircraft Meteorological Data Relay (AMDAR) is a program initiated by the World Meteorological Organization. AMDAR is used to collect meteorological data worldwide by using commercial aircraft. Data is collected by the aircraft navigation systems and the onboard standard temperature and static pressure probes. The data is then preprocessed before linking them down to the ground either via VHF communication (ACARS) or via satellite link ASDAR. A detailed description is given in the AMDAR Reference Manual
Aircraft Meteorological Data Relay
16354741
and Sweden have high-band VHF FM hunting allocations (see section on Sweden below), many hunting radios are marketed with both the 6 Nordic channels and 7 Swedish channels in one unit. Similar to Norway, Sweden also has Jaktradio (Hunting Radio) allocations, 6 channels in the 155.400–155.525 MHz band and 40 channels in the 30–31 MHz band. In addition to these, the general purpose channel 156.000 MHz is available. 156.000 MHz is sometimes included as Marine VHF radio "channel 0" or "M1" (private) channel, allowing communication between portables and radios mounted in boats. Modulation is FM, maximal power 4 watts for
Personal radio service
16354733
for 16 channels from 446.00625 MHz to 446.19375 MHz with 12.5 kHz channel spacing steps has been complimented with two digital channel plans (sometimes called "DMR446" or "DPMR446"). Digital FDMA offers another 16 channels from 446.103125 MHz to 446.196875 MHz with 6.25 kHz channel spacing steps. 4-level FSK modulation at 3.6 kbit/s is used. Digital DMR Tier I TDMA PMR446 channels are also available, eight channels from 446.10625 MHz to 446.19375 MHz with 12.5 kHz channel spacing steps. 4-level FSK modulation at 3.6 kbit/s is used. All three of the PMR446 channel plans occupy the same European-harmonized 446.0 MHz to
Personal radio service
4431102
3 to the current, post-transition VHF channel 12. Through the use of PSIP, digital television receivers continued to display the station's virtual channel as its former VHF analog channel 2.1. WBBM-TV is currently the only "full-power" television station in Chicago that operates its digital signal on the VHF band (as it had done prior to the June 2009 digital transition). WBBM-TV's rival station, WLS-TV, was the only other station to have operated its full-power digital signal on a VHF allocation until the station moved its digital broadcasts to UHF channel 44, in order to alleviate reception problems, although it retained
WBBM-TV
14345452
correct sequence and at an appropriate speed caused the aircraft to fall below its glide slope, roll to the right in a nose-high attitude, and crash. The accident report noted that YA-FAR had a full and "serviceable" instrument panel, a working VHF omnidirectional radio range (VOR) system and Instrument landing system (ILS) equipment. "Satisfactory and routine" communication between air traffic control and the aircraft was noted, and the cockpit voice recorder was recovered. There was also a flight recorder unit in the rear of the fuselage, and this was recovered on 6 January and its contents analysed. The Captain's decision
Ariana Afghan Airlines Flight 701
13897366
AN/MRN-2 The AN/MRN-2 was a Radio Range set used by the Army Air Force during and after World War II, it replaced in part the SCR-277. The set is a ground mobile, two course, VHF aural Radio Range with station identification, periodic sector identification and simultaneous voice transmission. it is a crystal controlled set and operates in the frequency range of 100 to 156 Mc. for use in guiding aircraft equipped with VHF radio receivers, such as SCR-522, to a landing field, or for use along ferry routes. effective range is 100 Miles. The AN/MRN-2 is mounted on a k-53
AN/MRN-2
8986690
its analog signal, over VHF channel 2, in May 2013, and "flash-cut" its digital signal into operation VHF channel 2. WYCX-CD WYCX-CD is a primary Heroes & Icons and secondary MyNetworkTV affiliated television station licensed to Manchester and Londonderry, as well as South Charlestown, New Hampshire. The station's digital transmissions are on VHF channel 2; it is also carried on area cable systems, and formerly branded as "TV 12 and 20" in recognition of this. The station currently brands as "YCN", an initialism for "Yankee Communications Network." WYCX-CD is owned by Cross Hill Communications. Programming is also seen on WYCU-LD
WYCX-CD
17897763
domestic broadcast. The short wave is reserved for international services (Voice of Turkey). The private companies however prefer FM band. According to a report by RTÜK, there are 63 nationwide, 113 regional, and 1129 local broadcasters. Turkey uses CCIR System B in VHF Band and CCIR System G in UHF Band. The color information is superimposed by PAL method. TRT uses both the VHF and UHF Bands. VHF is reserved for TRT 1 and UHF for the others. The private broadcasters use UHF band. According to the regulation a channel difference of at least 3 channels (21 MHz in VHF
Radio and television technology in Turkey
2507971
used for both voice and data connections. External antennas and amplifiers may be used to boost signal transception. It is not uncommon that chasers travel in small groups of cars, and they may use CB radio (declining in use) or inexpensive GMRS / FRS hand-held transceivers for inter-vehicle communication. More commonly, many chasers are also ham radio operators and use the 2 meters VHF and, less often, 70 cm UHF bands to communicate between vehicles or with Skywarn / Canwarn spotter networks. Scanners are often used to monitor spotter, sometimes public safety communications, and can double as weather radios. Since
Storm chasing
3682442
and generally not a technique used at VHF/UHF. Many other large UHF-/VHF-transmitters use diplexers. The number of transmitters which can share an antenna is restricted by the spacing of their frequency bands. Transmitters whose frequencies are too close together cannot be combined successfully by a diplexer. Diplexers are also used at medium wave broadcasting stations. However their use is not that common in this frequency range because the corresponding wavelength varies much more across the medium wave band than across the FM band and so it is more practicable to use a separate antenna for each frequency: medium wave transmission
Diplexer
20671473
narrative media as well as film and television, including the TLC series "While You Were Out" and HGTV's "FreeStyle". Other production clients include Discovery Channel, WE tv, and Universal Music Group. The company is currently working with actress Gabriella Pizzolo to produce voice over for a Nickelodeon series. Voice Coaches Voice Coaches is a voice-over production and training company headquartered in Albany, New York. Company services include voice-over and communication training as well as voice-over recording and production. Voice Coaches is owned and operated by composer, producer, sound designer, and voice over director David Bourgeois and his wife Anna. Voice
Voice Coaches
5432961
KAET KAET, virtual and VHF digital channel 8, known as Arizona PBS on air, is the PBS member television station in Phoenix, Arizona. It broadcasts a high definition digital signal on VHF channel 8 from a transmitter on South Mountain in Phoenix. Its signal is relayed across Arizona on a network of 13 translator stations. Owned by the Arizona Board of Regents and operated by Arizona State University, KAET maintains studios at the Walter Cronkite School of Journalism and Mass Communication on the campus of ASU Downtown Phoenix. KAET was launched on January 30, 1961, as an affiliate for National
KAET
20464866
industrial supporters, academic, and governmental organizations. All collected raw data is archived in a large historical database, containing over 10 trillion air traffic control messages (October 2018). The database is primarily used by researchers from different areas to analyze and improve air traffic control technologies and processes. The main air traffic control communication technologies currently used by the OpenSky Network are the Automatic Dependent Surveillance-Broadcast (ADS-B) and Mode S. Both technologies provide immediate and detailed aircraft information over the publicly accessible 1090 MHz radio frequency channel using software-defined radio receivers. Currently, the network tracks and displays several thousand flights at
OpenSky Network
1943761
147 standard of digital audio broadcasting (DAB) for creating a digital radio service, the United States has selected IBOC technology for its digital AM and FM stations. The band used for terrestrial DAB in the UK is part of VHF band III, which does not suffer from L-band's significant line-of-sight problems. However, it is not available in North America since that span is occupied by TV channels 7 to 13 and the amateur radio 1.25 meter (222 MHz) band. The stations currently occupying that spectrum did not wish to give up their space, since VHF offers several benefits over UHF:
In-band on-channel
8088266
codes such as Baudot or ASCII. The development of prosigns began in the 1860s for wired telegraphy. They are distinguished from common Morse abbreviations. Since Morse code communication preceded voice communications by several decades, many of the much older Morse prosigns have exact equivalent procedure "words" for use in the more recent radio telephony (voice). Prosigns may be represented in printed material either by a sequence of dots and dashes, or by a sequence of letters, which, if sent without the normal inter-character spacing (concatenated), correspond to the prosign symbol. There are at least three methods used to represent Morse
Prosigns for Morse code
8775931
Trunking mode it's a free-for-all site. IR sites are generally used for a small geographic area or to fill in holes. For sites that are used to fill in coverage traffic is very limited. To allow as limited a number of channels for use, and to be spectrum efficient, Voice On Control (VOC) was developed to permit the control channel to temporarily act as a voice channel. This allows as little as one channel per site, but access must be severely restricted to the site or communication problems will occur. When all channels at a VOC enabled site are in
Motorola Type II VOC
13503983
Automated Maritime Telecommunications System Automated Maritime Telecommunications System (AMTS) is a commercial mobile radio service used within the United States. It operates within the VHF frequency range, just above the North American Band III television range, and offers both voice and data communications to maritime customers. The system is operated by a network of private carriers across the country, with coverage primarily including coastal and inland waterways. In 1981, the FCC proposed the Inland Waterways Communication System (IWCS), a commercial maritime radio service with the proposed purpose of expanding private maritime communication and that was to operate from 216 to
Automated Maritime Telecommunications System
11425232
Filipino Monkey "Filipino Monkey" is a taunt used by radio pranksters in maritime radio transmissions since at least the 1980s, especially in the Persian Gulf. This taunt is also used as a name for pranksters who make odd, confusing, or even threatening calls on VHF marine channel 16, which is the VHF calling and distress channel. Before the advent of GMDSS, ships at sea were required to monitor the channel, which is meant to be used only to make contact before changing to a working channel. In the late 1980s in the Persian Gulf, there was much Filipino imported labor,
Filipino Monkey
11425238
may, in fact, be that of a prankster given the nickname 'Filipino Monkey'. Filipino Monkey "Filipino Monkey" is a taunt used by radio pranksters in maritime radio transmissions since at least the 1980s, especially in the Persian Gulf. This taunt is also used as a name for pranksters who make odd, confusing, or even threatening calls on VHF marine channel 16, which is the VHF calling and distress channel. Before the advent of GMDSS, ships at sea were required to monitor the channel, which is meant to be used only to make contact before changing to a working channel. In
Filipino Monkey
18836036
and enabled a multi-carrier force to maintain a high-speed formation at night or in foul weather. The new navigational tool known as the Dead Reckoning Tracer was also implemented for navigation and tracking of surface ships. Identification Friend or Foe (IFF) was used to identify hostile ships and aircraft, especially at night or in adverse weather. The four-channel Very High Frequency (VHF) radio permitted channel variation in an effort to prevent enemy interception of transmissions. It also allowed for simultaneous radio contact with other ships and planes in the task force. Beginning in March 1943, one visually very significant change
Essex-class aircraft carrier
11579778
with additional components to send the response to the Y-Gerät ground station for the ground station to derive range. Also derived the azimuth signal and displayed the results on the ANF 2 display giving the pilot a left/right command. Operating frequency 24 - 28 MHz. 8 Watts transmit power. The unit also interfaced to the FuG 10 system in the aircraft so that voice communication with the pilot from the ground controllers via the Fug 28a was possible. Hermine: This system was a VHF radio beacon. Originally developed in 1942 due to problems the design was suspended. When in 1944
Luftwaffe radio equipment of World War II
20101095
AN/ARC-182 The AN/ARC-182 is a family of military aircraft radio transceivers designed for two-way, multi-mode voice communications over a 30 to 400 MHz frequency range. It covers both Ultra High Frequency (UHF) and Very High Frequency (VHF) bands with AM, FM, as appropriate. The ARC-182 radio supports the HAVE QUICK II anti-jam waveforms, with an optional control unit. It features a guard channel capability for monitoring 40.5, 121.5, 156.8 and 243 MHz. Transmitter minimum power is 10 watts, AM, and 15 watts, FM. The RT-1250A model radio can communicate with other avionics over a MIL-STD-1553 data bus. Developed in the
AN/ARC-182
15028792
time of the Battle of Britain had two channels and the operating frequencies of the two could only be selected before take-off. One channel was used for voice communication between the aircraft and the other for communications with sector control, which was also used by the "pip-squeak" system. With the channels set to squadron-specific frequencies, the TR.9D limited the ability to coordinate with other squadrons. The set was low power, with a range of about air-to-ground and air-to-air, which presented numerous problems with reception quality. The TR.9 originally operated on a band that was relatively empty, but by the time
Dowding system
16752385
Munich Air Traffic control. Nine minutes later the pilot of Flight 802 changed flight plans from Instrument Flight Rules (IFR) to Visual Flight Rules (VFR). Innsbruck had no instrument approach procedures and "Flight" described it as "generally regarded as one of the most difficult airports in Europe". As it passed over Innsbruck VHF omnidirectional range station, the aircraft was still unable to break through the clouds. Snow flurries were falling. At 2:12 p.m., the crew of Flight 802 reported that they were at . This was the last communication received from the aircraft. Several minutes later, Flight 802 flew into
British Eagle International Airlines Flight 802
518309
channel spacing of 200 kHz, with a maximum frequency deviation of 75 kHz, leaving a 50 kHz buffer above the highest and below the lowest frequency to reduce interaction with other channels. AM broadcasting uses a channel spacing of 10 kHz in the U.S. and 9kHz in most other countries (such as the UK, Australia and New Zealand, but with amplitude modulation frequency deviation is irrelevant. FM applications use peak deviations of 75 kHz (200 kHz spacing), 5 kHz (25 kHz spacing), 2.5 kHz (12.5 kHz spacing), and 2 kHz (8.33 kHz spacing). Frequency deviation Frequency deviation (formula_1) is used
Frequency deviation
9947730
Up to eight batwing antennas are usually stacked vertically and fed in phase to make a high gain omnidirectional antenna for TV broadcasting. The wide bandwidth was needed at the low VHF analog TV broadcast band, as the 6 MHz TV channel bandwidth was about 10% of the frequency. Circular polarization was used for spacecraft (satellite and missile) communication, since circular polarization is not sensitive to the relative orientation of the antennas, and the space vehicle's antenna could have any orientation with respect to the ground antenna. High gain Yagi turnstile antennas were often used for the ground station. The
Turnstile antenna
588825
through effective approach spacing. Crew resource management (CRM) procedures are often used to ensure this communication process is efficient and clear. Within ATC, it is usually known as TRM (Team Resource Management) and the level of focus on TRM varies within different ATC organisations. Clearance delivery is the position that issues route clearances to aircraft, typically before they commence taxiing. These clearances contain details of the route that the aircraft is expected to fly after departure. Clearance delivery or, at busy airports, Ground Movement Planner (GMP) or Traffic Management Coordinator (TMC) will, if necessary, coordinate with the relevant radar centre
Air traffic control
20686339
as soon as it started transmitting. In regions with no elevated sights for line-of-sight, Barrage balloons with attached receivers or established in slow flying aircraft were used. Bases for the close-range field DF units were established in suspected areas. In is evident, from the enormous area of operations, that a successful directing of troops in the field can be accomplished only if good communications facilities were available. For this Radio communication was used. The monitoring stations had the following duties: The VHF intercept stations used the following equipment: Each team consisted of a team leader, who was a W/T operator
Funkabwehr