Before all the technological innovations we have today were invented, people had to refer to maps to orient themselves towards their destination and there were almost no ways to communicate with people in the area surrounding them. Imagine how basic the tools used by renowned explorers such as Christopher Columbus were compared to ours yet they were still able to travel from one country to another. Today, every large boat and airplane has a guiding system to help them reach their final destination, among many other technological advancements. One of these advancements is Direction Finding (along with Direction Finding Antennas) and it will be the topic of our article.
Discover Direction Finding (DF)
Direction finding is referring to the measurement of the direction from which a received signal was originally transmitted. These signals can be coming from radio transmissions or from any other types or wireless communications. With a DF system, the source of a transmission is located in space in space using a triangulation technique by merging Direction Finding from 2 or more spaced receivers or 1 mobile receiver. It is used for many usages like ship and aircraft navigation, finding emergency signals during search and rescue situations, animal tracking and locating illegal or interfering transmitters.
Direction Finding systems can be used with any radio source but the receiver antennas’ size depend on the wavelength signal. Low frequencies are to be used with big antennas, have very long wavelengths and are used mostly for ground-based applications such as marine radio navigation. On the other hand, higher frequencies require smaller antennas and are ideal for aerial applications. Finally, DF is an important part of the elaboration of military strategies since they are utilized in signals intelligence systems.
Learn More About DF Antennas
By the way they are built, DF Antennas have to be directional, which means that have to be more sensitive in certain directions than in others.
Loop aerial antennas are one type of Direction Finding Antenna. It essentially is an open loop wire on an insulating former or a metal ring that acts as the element of the antenna. In antennas like these, the loop’s diameter is 1/10 of a wavelength or smaller (it depends on the target frequency). This type of antenna is least sensitive to signals that it receives on its face and most responsive to those that meet it edge-on.
To resolve issues brought by bi-directional signals, a sense antenna is used. Sense antennas do not have directional properties but have the same sensitivity as loop aerial antennas. When a steady signal from a sense antenna is added to an alternating signal of a loop aerial antenna, you get a single position as the loop rotates 360 degrees at which the current is 0.
This ends our article on Direction Finding and Direction Finding Antennas. We hope that reading it has helped you understand what they are about.