Does a magnetic loop antenna need to be grounded?
Loop antennas do not require any ground plane, and actually perform slightly better without one. In reality however, as the rest of the application circuitry is positioned beside the antenna the antenna properties are effected by this proximity in terms of impedance and radiation properties.
What is the impedance of a loop antenna?
The input impedance of a loop antenna at natural resonance is quite high, ranging anywhere from ~10 kΩ to 50 kΩ. This characteristic high input impedance is a result of the loop antenna operating in a parallel-resonant mode at the desired frequency of operation.
Is a magnetic loop antenna directional?
◎ A loop antenna is very directional. Rotate the loop element until your receiver’s signal strength meter (S-meter) deflects to maximum and the incoming signal sounds clearest.
How do I choose a balun?
Select a balun closest to the antenna feedpoint impedance (you’ll have to get this from textbooks or modeling), and use it at the feedpoint or where the feedline from the antenna ends. Be sure the feedline between the balun and antenna feedpoint matches the antenna impedance as closely as possible.
How is loop antenna calculated?
The formulas for calculating the approximate length of a full-wave loop antenna are: Full-wave loop in feet = 1005 / frequency in MHz. Full-wave in meters = 306 / frequency in MHz.
How high does a loop antenna need to be?
about 3 feet
Minimum mounting height is 1 loop diameter high (about 3 feet or higher) off an earth ground. Place the Alpha Loop higher, so it sees above and past obstacles. The physical environment that surrounds antennas will have an impact on performance. Consider this when placing an antenna to enhance performance.
Does grounding an antenna reduce noise?
To lower the incoming noise on a dipole antenna, connect a ground wire to the coax fitting at the antenna base. Run it to a ground rod and enjoy hearing stations that were covered up before.