With the RFMAX Power Mapper you're no longer working in the dark. This meter is specially designed to show nulls in the UHF radio field at large distances from the antenna. You will find it hard to believe how large the signal variation can be, even quite close to the antenna. The meter will show polarization effects and destructive null cancellations, ground and water absorption. The meter relies on the power in the radio waves, so it cannot give a fails reading or have a flat battery. Almost 100% of the signal on at the antenna is shown on the meter, giving a massive 10+ meters (30+ feet) range.