An evidence review of active and passive interference, frequency selection, signal margin, transmitter power, housing effects, calibration, and field verification. Electromagnetic interference can degrade HDD tracking before a receiver loses the transmitter signal. Depth, pitch, roll, and position may still appear on screen even when the margin between the transmitter field and the surrounding electromagnetic […] The post HDD Tracking Under Electromagnetic Interference: What Determines Locator Reliability? appeared first on DAILY CIVIL .