A symmetrical dipole antenna has a weak bidirectional pattern, allowing the antenna to be oriented towards the correspondent, thereby reducing the impact of external interference on the receiver input. There are two types of symmetrical dipoles: the split dipole and Pistolkor’s loop dipole. The latter has the same radiation pattern as the split dipole but its characteristic impedance is 300 Ohms. High impedance facilitates matching the antenna with a feeder when using multi-element antennas, as increasing the number of elements lowers the antenna’s input impedance.
The advantages of symmetrical loop dipole antennas of the Pistolkor type include simple design, wide operating bandwidth, low sensitivity to industrial noise, and the ability to slightly adjust the radiation pattern.
This type of antenna was proposed by Russian scientist Alexander Pistolkor. The design of the Pistolkor loop dipole consists of two parallel linear dipoles forming a loop. These dipoles are placed at a small distance from each other relative to the wavelength and form a closed loop. One dipole has a central gap where the feeder is connected. The center of the other dipole is a point of zero potential, allowing it to be mounted to a metal mast without insulation. The advantage of the loop dipole is its higher input impedance and the ability to adjust it by selecting an appropriate conductor radius.
The typical input impedance of a half-wave Pistolkor dipole is 300 Ohms, allowing it to be fed with a 300-Ohm balanced line.
Related sections:
Aperture Antenna, Stationary Antenna, SWR, Radiation Pattern, Wave Polarization