Electric field sensors in electromagnetic sounding
A staked and an insulated dipole antenna were used to monitor transmissions from a distant very-low-frequency transmitter. The field strength recorded from the staked antenna was found to be much larger than that recorded from the insulated antenna. It is shown that this can be adequately described as magnetic field induction. It is postulated that an insulated antenna is a far better electric field probe for surface impedance investigations including audio magnetotelluric (AMT), controlled source audio magnetotelluric (CSAMT), and VLF sounding techniques. >