From Embedded Antenna Design: "LP-MAG-390 390 MHz Compact Magnetic Antenna"
About Symmetry Electronics Team
The LP-MAG-390 is a low profile 390 MHz compact Magnetic antenna designed for UHF applications covering 380–400 MHz including some TETRA frequencies. This antenna is robust and durable and ideal for outdoor applications where long antenna whips are undesirable.
The magnetic base is 90mm in diameter and the overall height is just 180mm enabling excellent RF performance whilst avoiding the draw backs of long whip antennas including issues such as damage from overhanging vegetation and other impacts when vehicles are operational. Apart from mobile applications, the LP-MAG-390 is also suitable for fixed applications where a discreet and non-permanent antenna solution is required.
The cable length can be a maximum of 3.5M (other bases are available with longer cable runs) and the connector type can be ordered to requirement.
For more information and pricing on the 390 MHz compact magnetic antenna, please contact your local EAD distributor or EAD directly for assistance.
The LP-MAG antenna can also be supplied at the following frequencies: 169 MHz, 433 MHz, 450 MHz, 868 MHz and 915 MHz. Other frequencies on request.
Source: https://www.ead-ltd.com/news/lp-mag-390-390-mhz-compact-magnetic-antenna