The length of the antenna is determined according to the wavelength of the center operating frequency;
Wavelength and frequency are the inverse relationships, the calculation formula:
Wavelength (unit: meter)=300/frequency (unit: MHz)
When the center frequency is 150MHz, the wavelength is 2 meters, so the signal around 150MHz is called a 2-meter wave;
And the wavelength of 430MHz is 0.7 meters, so the signal around 430MHz is called a 70cm wave.
The length of the antenna is proportional to the wavelength, so it is inversely proportional to the frequency. The higher the frequency and the shorter the wavelength, the shorter the antenna can be.
The length of the antenna is not equal to one wavelength but is often 1/4 wavelength or 5/8 wavelength.