High frequency is the ITU designation for the range of radio frequency electromagnetic waves between 3 and 30 megahertz. It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters.

What are HF radios used for?

HF communications are best suited for long distance communication between ground operators and base stations. The field benefits of VHF over HF radio is in their relative immunity to space weather conditions or electrical interference.

Is HF radio still used?

Despite advances in the undersea cable and SATCOM domains, HF communications are still in use. For example, radio amateurs use parts of the HF band to communicate with their contacts around the world.

Who uses HF radio?

The band is used by international shortwave broadcasting stations (3.95–25.82 MHz), aviation communication, government time stations, weather stations, amateur radio and citizens band services, among other uses.

What is the difference between HF and UHF?

UHF systems are known for generating long read ranges, up to twelve meters (forty feet), whereas HF systems carry a much shorter read range of approximately one meter (three feet). UHF allows for a faster data transfer rate, up to 20 times the range and speed of HF systems.

Radio Fundamentals: An Introduction to HF | Codan Radio Communications

What frequencies are considered HF?

High frequency (HF) is the ITU-designated range of radio frequency electromagnetic waves (radio waves) between 3 and 30 MHz. It is also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters (ten to one hundred metres).

How far can HF transmit?

But the real advantage of HF is skywave propagation, where a single link can span distances as great as 3,000 km (a little less than 1,900 miles). Skywave propagation occurs when the radio wave is refracted (bent) in the uppermost layer of the atmosphere, called the ionosphere.

Does the military use HF radio?

The primary HFGCS voice frequencies are 4724.0 kHz, 8992.0 kHz, 11175.0 kHz, and 15016.0 kHz. In addition to the HFGCS, U.S. aircraft frequently use Military Auxiliary Radio System (MARS) HF stations (13927.0 kHz) and Canadian Forces HF stations (11232.0 kHz) to relay messages.

Does radio need HF?

The real answer is this: you need HF if you fly beyond line-of-sight radio communications. Having SATCOM (including SATVOICE) or CPDLC does not relieve you of this requirement.

Can HF be jammed?

Alternatively, recent advances in RF front-end and software defined radio technologies have suggested that HF radios can be intrinsically hardened so that they can withstanding and survive interference and jamming attacks without causing service interruption and even suffering electrical damages to the circuitries.

What HF frequency is best?

HF users have found that using a frequency that is the MUF times 0.85 gives the best chance for good results. This is called the frequency of optimum transmission (FOT).

Which radio is commonly used for high frequency communications?

VHF- Very High Frequency

Very high frequency is commonly used for FM radio broadcast, two-way land mobile radio systems, long-range data communication, and marine communications, just to name a few. VHF includes radio waves from 30 MHz to 300 MHz.

Why is HF called shortwave?

Shortwave radio received its name because the wavelengths in this band are shorter than 200 m (1,500 kHz) which marked the original upper limit of the medium frequency band first used for radio communications. ... Early long-distance radio telegraphy used long waves, below 300 kilohertz (kHz).

Is HF line of sight?

HF (3-30 MHz) radio waves propagate either as line-of-sight (space) or sky waves. Sky waves are the most useful to understand because they provide the longest geometric range possible (independant of transmitted power).

What length wave is required for HF communication?

High-frequency (HF) radio is in the 100- to 10-metre wavelength band, extending from 3 megahertz to 30 megahertz.

Which is better UHF or VHF?

UHF is the better all around signal and is by far the most popular, so if you are in doubt, choose UHF. UHF signals don't travel quite as far outdoors as VHF signals, but they do a better job of penetrating wood, steel, and concrete, giving you better range and performance in urban environments and around buildings.

When would you use the VHF FM radio?

Common uses for radio waves in the VHF band are Digital Audio Broadcasting (DAB) and FM radio broadcasting, television broadcasting, two-way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometers with radio modems, amateur radio, and ...

Why different HF frequencies are used during the day and at night?

Because HF radio waves depend upon the ionosphere for reflection, their propagation is affected by changes in the ionosphere. ... A good rule of thumb for the time of day is that the higher frequencies are best during daylight (10 to 29.9999 MHz) and lower frequencies work best at night (2 to 10 Mhz).

Why HF and VHF is used in aviation?

Above HF transmissions, radio waves are known as space waves. They are only capable of line-of-sight transmission and do not refract off of the ionosphere. ... VHF radios are used for communications between aircraft and air traffic control (ATC), as well as air-to-air communication between aircraft.

What are the MARS frequencies?

The Mars Relay uses frequencies of 437.1 MHz for transmission, and 401.5 and 405.6 MHz for reception. Because these frequencies are near the radio amateur bands, Hams will have the opportunity to help out NASA and listen for the Mars Relay beacon transmission at 437.1 MHz.

Is HF easy to jam?

One of the most difficult ways to communicate by radio is over the high-frequency (HF) bands. These channels, which lie between 2 MHz and 30 MHz, are touchy and unpredictable, prone to noise, fading, jamming, and interference.

What is a ship to shore radio?

Marine VHF radio is a worldwide system of two way radio transceivers on ships and watercraft used for bidirectional voice communication from ship-to-ship, ship-to-shore (for example with harbormasters), and in certain circumstances ship-to-aircraft.

Can HF radios communicate with VHF?

Connecting VHF and HF radio

It is important to remember that VHF and HF radio are used for communicating over different distances because of the way signals travel. VHF waves are only effective along a line of sight between a transmitting and receiving antenna.

How does a HF radio work?

HF frequencies (between 3-30 megahertz) are transmitted from a base unit or handheld transceiver into the Earth's atmosphere. These radio signals 'bounce' off the ionosphere and return to land, where they are received by another transceiver tuned into the same radio band.

Who invented HF radio?

Amateur radio came into being after radio waves (proved to exist by Heinrich Rudolf Hertz in 1888) were adapted into a communication system in the 1890s by the Italian inventor Guglielmo Marconi.