Transmitting Omnidirectional Antenna
The antenna is the air interface connection between the Python Detector and the transmitted signal from a emergency services vehicle.
Antennas come in may forms and sizes but the most common types of antenna used in mobile communications are Monopole or Dipole antennas and are Omnidirectional antennas. The radio waves from a transmitting Omnidirectional antenna radiate power uniformly in all directions on the horizontal plane.
The transmitting antenna radiates maximum power in the horizontal plane and this decrease with elevation above or below this horizontal plane and falls to zero at the antenna's axis and viewed from the side the radio waves from a transmitting Omnidirectional antenna form a doughnut shape.
Omnidirectional antennas are oriented (polarized) vertically. Dipole antennas are ground independent, meaning they are designed to perform efficiently with a minimum or no ground plane.
The length of the antenna is one important factor on its overall performances, the length is determined by the radio frequency that you want to transmit or receive on, and its wavelength. The antenna length can be calculated by this simple formula: λ = c / f
λ = wavelength
c = speed of light (299,792,458 Meters Second)
f = frequency (382500000 MHz) for a Tetra Received Signal
We can calculate the wavelength and full antenna length:
299,792,458 ÷ 382500000 = 0.7833 Meters (783.3mm)
To make this full antenna length more practical for day to day applications the length can be reduced in whole number multiples, these are often referred to as 1/2, 1/3, 1/4 and 1/8 wave antennas.
For example a 1/4 wave Tetra antenna would be:
783.3 / 4 = 195.8mm
Antenna gain is the relative measure of an antenna's ability to direct or concentrate radio frequency energy in a particular direction or radiation pattern. In a receiving antenna such as used in Python, the gain is how well the antenna converts radio waves arriving from a specified direction into electrical power. When no direction is specified, "gain" is can be referred to the peak value of the gain, the gain in the direction of the antenna's main lobe.
Antennas Radiation Patterns:
Dipole antennas are oriented vertically and are typically used for non-directional applications where the received signal can be detected from all directions (360 degrees). The types and positions of the antenna and their radiation pattern can determine the detection capability.
Antennas and Accessories:
We have a number of different antenna options available from our store, please click on the below buttons for more information:
You can easily upgrade to our Higher RF Gain windscreen mounted antenna without the need for any special tools
You can increase the detection range of your detector by fitting a Magnetic Mounted High Gain RF Antenna
Our replacement Standard Antenna can be obtained from our store should it be required
Our 5 metre RF extension cable allows you to mount our Higher RF Gain windscreen antenna in different locations