HF Antennas - Largest Selection with High Availability
Because of the properties of the ionosphere, short wave enables worldwide communication - if you have the right antenna. No matter if directional antenna, a wire dipole or a vertical antenna - each design offers its own advantages and disadvantages. To find the right product for your own situation is not always easy. WiMo helps you with its many years of experience in amateur radio and marine radio.
What antenna length do I need for which frequency?
The required antenna length for a specific frequency in amateur radio depends on the wavelength of the frequency to be received or transmitted. A rule of thumb is that for optimal transmission the antenna should be half the wavelength of the frequency (λ/2), and at the feed point this length should be divided by 2 so each side should measure (λ/4). To calculate the wavelength, one must divide the speed of light (approximately 300 million meters per second) by the frequency in hertz. The result gives the wavelength in meters. To get a quarter of the wavelength, divide this value by four. For example, for the frequency of 145 MHz (2 meter band) you need an antenna of about 0.5 meters because the wavelength is about 2 meters (300/145 = 2.07, then 2.07/4 ≈ 0 ,5).
Rodrigo "Rod" Herrera
https://www.wimo.com/en/author/rodrigo-herrera
What does impedance mean for antennas?
Antenna impedance refers to the resistance that the antenna presents to alternating current at its frequency and is a measure of the relationship between voltage and current at a particular point on the antenna. It is expressed in ohms. A good impedance match between the antenna and the connected radio transmitter or receiver is crucial to ensure effective transmission and the best possible reception, as it minimizes power losses. Common impedance values are 50 ohms for coaxial cable connections.
Rodrigo "Rod" Herrera
https://www.wimo.com/en/author/rodrigo-herrera
What is meant by half the wavelength of an antenna?
An antenna's half wavelength, also known as a half wave dipole, refers to an antenna whose length corresponds in a certain way to the frequency of the signal to be transmitted or received. Specifically, the antenna is as long as half the wavelength of the signal in free space. This sizing allows the antenna to be resonant at the appropriate frequency, providing maximum efficiency when transmitting or receiving radio waves. The physical length of the antenna is important to its tuning and its ability to effectively use specific frequencies.
Whether you have questions about our products, the ordering process or our services, whether you are a complete professional or a beginner - it doesn't matter! Our experts are there to help you in word and deed - independent of the frequency range and radio application.