The depth up to which GPR can penetrate is dependent on: Medium to scan, Transmitted Wave Frequency (frequency of the antenna) and Radiated Power The penetration depth decreases when the electrical conductivity of the medium is high. This is because the high value attenuates the waves. High frequency gives high-resolution results but lower penetration depth. Lower frequency gives great depth with low resolution. Hence, the choice of frequency is dependent on the objectives and the depth of the survey path. Always test more than one frequency and fix a final one. For high-resolution applications like rebar or conduit locations, a high frequency of 1000 MHz can be used, which gives a penetration depth of 24 inches. For using GPR in soils, a lower frequency of 12.5 to 500MHz gives a deeper penetration.