Advantages and disadvantages of rod antenna

The advantages of rod antenna are arbitrary bending, beautiful and durable, ultra-wide receiving frequency band and good directivity; The disadvantage is that the short-wave sensitivity is very general when using the rod antenna, and the rod antenna often breaks due to improper use, and it is difficult to pull out the remaining antenna after breaking.

Theoretically, the natural frequency of a rod antenna (half-wave oscillator) depends on its length. Its length is a quarter of the wavelength of radio waves in air (calculated in vacuum), so this antenna presents pure resistance. The impedance is 75 ω.

In fact, in order to shorten the length of the antenna for convenience of use, an inductor should be connected in series to the antenna. Because the antenna shorter than the standard value is no longer purely resistive, but capacitive, a certain inductance must be connected in series to compensate its distributed capacitance.

Classification:

1, which can be divided into transmitting antenna and receiving antenna according to the working nature.

2, according to the purpose can be divided into communication antenna, broadcast antenna, TV antenna, radar antenna, etc.

3. According to directionality, it can be divided into omnidirectional antenna and directional antenna.

4. According to the working wavelength, it can be divided into ultra-long wave antenna, long wave antenna, medium wave antenna, short wave antenna, ultrashort wave antenna and microwave antenna.