Popularity of ISM 433 MHz band is high in many countries. The company IK-Telecom offers collinear antennas with excellent directional diagram and good matching. Traditional radials are replaced with a current balun, it also increases reliability of the antenna. Gain of 7 dBi dramatically increases a radio covering of any telemetry system. The feed line is reliably protected from bad weather. All antennas are surely checked on compliance of SWR parameters.
A7-433 E-plane pattern
A7-433 VSWR diagram