What are MF and HF frequencies?
Medium Frequencies (MF) designated for marine communication range between 1605 kHz to 3800 kHz and are called “t” band. High Frequencies (HF) designated for marine communication range between 4000 kHz to 27500 kHz and are called “u” band. Only the first five are used for distress and safety communication.
How are HF signals propagated?
When using HF propagation via the ionosphere, the radio signals leave the transmitting radio antenna on Earth’s surface and travel towards the ionosphere where some of these are returned to Earth. The radio signals travelling away from the Earth’s surface are termed sky waves for obvious reasons.
What is the general rule for the use of MF HF frequencies?
The basic rule when using HF radio, is to know how far (approximately) you are trying to communicate. Once that distance is known then it is a simply a matter of selecting an appropriate frequency.
What is the HF emergency frequency?
121.5 MHz
121.5 MHz is the civilian aircraft emergency frequency or International Air Distress frequency.
What is a MF HF?
MF/HF radio station is a high tech equipment, designed for receiving and transmitting messages between vessels in the medium and high frequency range. It usually consists of a transceiver, a control block, and an antenna. An MF/HF radio installation with DSC should be installed with a TELEX terminal.
What is HF SSB?
Single sideband (SSB) is the most popular mode of voice transmission on the HF bands in ham radio. The mode got its name from a key difference from the older mode, AM, which is used by AM broadcast stations and was the original voice mode that hams used.
What is HF wave propagation?
HF (3-30 MHz) radio waves propagate either as line-of-sight (space) or sky waves. Usually the straight line distance is limited by the horizon (the point where the straight line path is tangent to the earth). A sky wave can extend the propagation path well beyond the visible horizon.
What are the two basic modes of high frequency HF propagation?
The true path radio waves take, however, is often more complex. There are two basic modes of propagation: ground waves and sky waves. As their names imply, ground waves travel along the surface of the earth, while sky waves “bounce” back to earth.
What is MF HF?
MF/HF radio station is a high tech equipment, designed for receiving and transmitting messages between vessels in the medium and high frequency range. It usually consists of a transceiver, a control block, and an antenna.
Which is the highest frequency for HF propagation?
HF propagation prediction is a statistical science. The maximum usable frequency (MUF)is the highest frequency that, with a probability of 50%of the time, can be used for radio communication between two points at a specified distance (but not necessary in all directions) via refraction by the ionosphere.
What is the skip distance of HF propagation?
Skip distance: The skip distance for a signal using HF propagation via the ionosphere is the distance on the Earth’s surface between the point where radio signals from a transmitter, transmitted to the ionosphere and refracted downwards by the ionosphere, to the point where they return to earth and are received.
How is HF propagation used in the military?
HF propagation is also widely used for broadcasting, military and many other organisations requiring long distance communications. HF propagation is also widely used by radio amateurs who are able to communicate across the globe.
How is ionospheric propagation used in the MF band?
HF Propagation: Ionospheric Radio Propagation Ionospheric propagation is one of the key modes of propagation used in the MF and HF bands enabling distances of thousands of kilometres to be reached. Ionospheric propagation tutorial includes….