Abstract: A device for indicating the intensity of the vertical component of an incnt electromagnetic field independently of the frequency or the direction of the field uses a dual-loop antenna, current transformers and a means for combining voltage signals. The two antenna loops are planar and the planes of the loops are disposed orthogonally to each other. The loops are arranged to intersect at a common central axis, and the loops are thus symmetrically disposed about the axis. When a source of electromagnetic radiation is incident on the antenna, a current is generated in the loops which is then transformed into a voltage and combined to produce an output which is independent of frequency, of the direction of the field, and is thus representative of the total vertical field intensity.