Category Archives :Radio knowledge

The start of amateur radio activities in our country is not too late. In the 1920s, Shanghai was already the economic and trade center of East Asia at that time. Not only commercial radio stations were introduced, but amateur radio activities were also brought into China.  ...

The history of the global amateur radio competition has been nearly 100 years, and it has almost accompanied the development history of the entire amateur radio DX communication.  ...

In recent years, amateur radios have popularly used digital modes for communication. Many ham friends have heard of the names of digital modes such as JT65 and FT8. Ham friends who have HF or 50MHz radio stations can hear many "beep-hoo-" tones at certain points in time on the frequencies in the table below. This is a kind of digital mode, FT8 signal.  ...

A link budget is usually used to estimate the longest distance for a signal to travel between transmitter and receiver. This is also the main method for evaluating the coverage range of a wireless communication system and is an important work in wireless network planning. So how to make a simple link budget?  ...

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".  ...