The user has to build his own small antennas. There is no need to have special skills since these antennas usually are simple and small. The type and the size of the specific antenna depends from the sensitivity requirements and environmental restrictions. There is a very detailed description of some antenna examples in the Active Antenna Amplifier technical documentation.

Here some photos from these documents.

large-loop-fig6

Single Loop

Single loop made form PE coated tube with aluminum layer for home heating systems.

two-loops-fig11

Crossed coplanar loops

Crossed coplanar loops made from PVC coated Cu wire 6 mm2. Each loop consists of 2 parallel connected wire circles to reduce the loop inductance. The loops are used also as arms of a small vertical dipole.

Two Loops

Two loops

Two loops in orthogonal planes.

4 crossed coplanar loops

Four crossed loops

Four crossed coplanar loops – a very sensitive system.

two-loops-fig11

Two crossed loops

Two crossed coplanar loops approx 1m diameter with heating tubes – the most often used design.

phased array

Phased array

An example of the elements of a phased array with 3 active antennas. B is the central element.