Magnetic bases for antennas are especially good for mounting on a metal surface. This surface serves as a grounding surface, which in most cases has a beneficial effect on the transmission properties of the antenna. The antenna becomes more directional at this point - the emission angle of the antenna narrows, thus increasing the gain. When the wave hits the antenna in the anti-phase, the antenna will be shaded from an unfavorable direction. An important aspect is also the VSWR magnetic base, which indirectly indicates the compatibility of the base to the connected antenna. VSWR should be as close as possible to a 1:1 ratio so as not to cause energy losses from impedance non-adaptation.
The characteristic impedance of these bases is usually 50 Ω.