Category Archives :Radio knowledge

We know that the shortest distance is straight line between two points. but it's often not simple when hams communicate with each other from around the world. Because it's not the shortest distance geographically if we connect two points directly on world map, we need to select the right direction of antenna to achieve the better communication effect. Especially for directional antennas, such as Yagi antennas. we must rely on the great circle Maps.  ...

For ham, it is very interesting to do some simple DIY to achieve some of your own special demands. Therefore, it is a simplest need to know the function of programming interface. Today we will take a look at several programming interfaces of Retevis and Ailunce.  ...

In amateur radio world, one of ham's favorite radios is the SDR transceiver. So what's SDR radio? What is the difference between SDR and traditional transceiver ? what are advantages and disadvantage of SDR? Let's study together.  ...

The specification of walkie-talkie is an important reference for us to know whether it meets our needs. For example, the working mode of walkie-talkies is often marked with words such as F3E or F2D. Do you know what it means? Today let's study together.  ...

NVIS is short for Near Vertical Incidence Skywave. It's short-range near field communication method which is widely used in military communications, nearby emergency rescue and other fields. NVIS and DW are the main methods of shortwave communication, so what is the difference between them?  ...

Digital filter can effectively filter out the frequency point of a specific frequency or the frequency other than the frequency point and is a device or circuit that has a signal processing effect. It is equivalent to the "sieve" of frequency.  ...

The collective Stations take part in the match in 1786 and 1987  ...

China's Amateur Radio Competition Set sail again in 1985  ...

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.  ...