Nearly all existing airborne EM-survey systems have been tested in Russian Federation. And for today the most popular EM-system is the frequency-domain one, called EM-4H. The article gives the description of the EM-4H system, that have been developed by «Geotechnologies» JS. This instrument allows effective conductivity mapping on a 1:25000 scale. It provides performing of 100 kilometers of survey per hour on the average.
