The HLC 27 is a compact dipole antenna for automotive immunity testing, embedded in a plastic housing. The original proposal of ISO 11452-9 had significant drawbacks, which made a practical realisation impossible. Especially the small effective antenna area, high losses and high sheath currents were the main disadvantages of the original design. A shortened dipol with balun, fitting into the original housing was choosen to eliminate the previous mentioned drawbacks. In order to maintain a high degree of symmetry, the coaxial antenna connector leaves the antenna at the center of the rear mounting bolt. This prevents the generation of unwanted sheath currents very effectively. A further reduction of sheath currents can be achieved using the optional coaxial cable loaded with clamp-on ferrites.
The antenna housing comes with two fixture bolts, which can be used to mount the antenna either in vertical or horizontal orientation.