Potential gradient is measured using a JCI Chilworth 131F fast response adverse conditions field meter, with operational health monitoring. It is mounted on a 2 m pole attached to the edge of the roof of the @Bristol building. Other buildings in the area are of a similar height to the @Bristol building. Ground level is 12 m a.s.l. Approximate instrument height 30 m a .s.l.

Linear response for the instrument was tested within a parallel plate system in the University of Bristol School of Chemistry. No comparison to calibrated measurements has been undertaken yet, but a comparison to a passive wire antenna nearby in Bristol traceable to a calibrated electrometer was planned for summer 2016

Data frequency is 10Hz.
Calibration of the field meter alongside was performed on August of 2010.

This is used in the Glocaem potential gradient network