How to Calculate Antenna Length for Frequency?
There are different kinds of antennas available, and they have different lengths. The length of an antenna varies depending upon the frequency and style of the antenna. There are several ways by which you can calculate the length of an antenna to determine its frequency.
Measuring the length of an FM radio antenna
FM Radio antennas work at a specific frequency range. The optimum length of an FM antenna can be measured easily by using some simple steps, but you must keep in mind that the design of the antenna creates a difference in its length, so it should be kept in consideration.
Following are some simple steps that can help you calculate the antenna length for frequency.
How to calculate the height of a standard antenna?
There are different formulas for the calculation of the height of different types of antennas. A general estimate of the antenna heights with their respective formulas is given below.
How to measure the height of a dipole antenna?
The length and height of dipole antenna are a determining factor of the frequency at which it works. By calculating the height of your dipole antenna, we can know whether it operates on HF or UHF frequency band. The physical length of dipole antenna is calculated even if it is half-wavelength dipole antenna.
However, there is a little difficulty while we calculate the height of a dipole antenna. The material length of the dipole antenna is not similar to the dipole antenna wavelength in free space. Mostly it is considered that the material or physical length of the dipole antenna is shorter as compared to its length in the space.
There can be various reasons why there is a difference in the material length of the antenna and its length in the space. It is because the surrounding space of the antenna is operating the signals around them, which provide a long length for the conduction of signals. So, there is less resistance in the path of signals, and the antenna length is ultimately increased.
While we calculate the length for your dipole antenna which is half-wave, the wave is thought to be traveling in the space around it. So for this purpose, the length of the antenna is augmented by a factor A. The value of this factor, however, Depends upon the model of radio, type of wire used in the radio and antenna, and the length of the antenna itself.
The point of having a length in space is quite ambiguous and unique in itself. There are hundreds of factors that can increase or decrease the electrical length of the antenna in space, making it more difficult to calculate the exact length of the half-wave dipole antenna. The obstacles in the way of signals like buildings, trees, and metallic objects are important factors to be considered while measuring the length of the antenna in free space.
Formulas for calculating the height of the antenna
These simple formulas for the calculation of antenna height and length are as follows.
What is the benefit of using a formula for the calculation of antenna height?
These formulas make the calculation process of antenna height much easier. When we have calculated the antenna height using simple formulas, it is a perfect point for calculating the antenna length. However, the presence of other things and obstacles cannot be denied and cause a difference in the physical length of the antenna.
So if you are about to make an antenna, it is better to keep the components of the antenna somewhat longer as compared to the values of calculations. It reduces the risk of you being short of the components of the antenna. Remember that once your antenna is made, its reduction is possible but adding body is not possible.
While you make any type of antenna, keep in check its performance. By doing this, you can calculate the optimum level of performance with a specific antenna.
Determining antenna length for common radio frequencies
A Dipole antennas is the most common antennas used everywhere and almost in every house. It is because reason that these antennas are necessary with Ham radios. There are some general lengths and frequencies of antennas mentioned to give you a general idea.
The estimated frequency band of about 1.8 megahertz the desired length for a half-wave dipole antenna is 266 feet. For the 3.5 megahertz frequency band, the required length is 137 feet. For the band of seven megahertz FM, we need a wire of about 68 feet in length.
Is it easy to calculate the height of an antenna?
It is quite an interesting question whether it is easy to calculate the height of an antenna with these simple formulas. Well, the answer for it is no. It is convenient to write and theoretically describe the height of an antenna but when we go on practical grounds, predicting the height of the antenna is not an easy process.