Some believe that electromagnetic waves can be measured with a portable device, but it is mistaken. A hand-held device (such as Gauss meter, also known as a ‘beeper’) can only measure the electric field and the magnetic field of a product which uses a low frequency band of 10KHZ or lower.
Accuracy is ensured when electromagnetic waves are measured on a standardized location with the standardized instruments and antenna in the standardized method.
This involves a shield room (a place unaffected by surrounding devices) or an open site (where no obstacles are present in the vicinity) where the object is placed, a set of certified instruments (spectrum analyzer) and antennas for measurement at a distance of 3M, 10M and 30M. These facilities are only available at few certification authorities, R&D centers of large companies and the RF Lab of Small and Medium Business Administration. Measurement of electromagnetic waves at home or in the office is not practical as the size of facility is huge and the instruments are expensive to acquire; an alternative is to take the product to one of these testing facilities.