VPMP 9242 Schwarzbeck Passive Monopole Antenna Base

Introduction：

The VPMP 9242 is a vertical and passive monopole antenna base manufactured by Schwarzbeck and sold under license to EUTTEST for use in linearly polarized passive monopole antenna receiving and transmitting applications with a 10 mm element mount for telescopic or biconical elements for use with antennas such as FBAB 9177, FBAL 9178, BBA 9106, BBAL 9136 antennas.

For increased efficiency, especially at frequencies below 25 MHz the VPMP9242 is equipped with a wideband toroidal transformer. In contrast to dipole antennas, monopole antennas are always asymmetrical and therefore braid currents are present in the coaxial feed cable. The effect of braid currents can be minimized by using as large a ground plane as possible to act as an RF balance on the one hand and to suppress braid currents (at least at high frequencies) on the other hand. In general, the use of a ground plane will improve reproducibility. If the coaxial feeder cable to the VPMP is contact sensitive, this indicates the presence of braid currents.

The following steps help to minimize the effects of unwanted braiding currents in monopole antennas:

• Connect the flange of the VPMP to the amplifier using a short, wide or low inductance metal strip;
• Use the largest possible ground plane;
• Use coaxial feeder cables with appropriate ferrites to suppress unwanted currents.

Technical parameters：

VSWR on BNC socket with FBAL 9178 element

Optional accessories:

Opt. GP: Ground reference plane 0.6 x 0.6 m