Category Archives :Radio knowledge

A repeater receives a signal on one frequency and simultaneously retransmits (repeats) it on another frequency. The frequency it receives on is called the input frequency, and the frequency it transmits on is called the output frequency.   ...

Let's talk about another important concept of the antenna: polarization.  ...

what are electromagnetic waves? how does the antenna send these electromagnetic waves out? how does the antenna realize the directional emission of electromagnetic waves? how do you measure the coverage and gain of the antenna's main lobe? After reading the article, you will understand.  ...

wireless communication also transmits information through antennas, except that it transmits electromagnetic waves that carry useful information. The figure below is an example of mutual communication between a mobile phone and a base station.  ...

Calling CQ is the easiest way to get on the radio and talk to somebody if you’re not turning around the band’s looking for someone else calling CQ, you can find a clear frequency and call CQ and see if someone out there hears you.   ...

The signal report of an amateur station consists of "R" (Readability, which is the clarity of the signal) that represents the intelligibility of the signal, "S" (Strength, that is, the size of the signal) that represents the strength of the signal, and "T" (Tone) that represents the tone of the signal , That is, the tonal quality of the signal) is composed of three parts, so the signal report is often called "RST".  ...

Mobile radio generally installed in the car. Its power directly come from car battery. The power of mobile radio is around 25-50w, with a high gain antenna, the communication distance is usually around 30 kilometers. This is not achievable with a handheld radio.  ...

antenna SWR, antenna gain, and Directionality are reference factors for judging the quality of an antenna.  ...

Who Uses Walkie-talkies When Cell Phones Are So Powerful?  ...

when we use ordinary Yagi antennas and hand antennas, we must rotate the direction, look for the signal, and then successfully receive it, and then carry out satellite communication.  ...