MFJ Ultrasonic Receiver pinpoints power line noise HF and VHF operation can be affected by noise on the bands which makes it hard to hear the weaker stations and adds to your fatigue. Many times the noise is coming just outside your doorway, from the power lines. Power companies are usually very willing to help out with noise issues, but not all companies in this age of financial limitations will have the necessary equipment or trained personnel to properly locate nearby noise sources. MFJ-5008 aids you in locating the noise sources generated by corona discharge and arcing components on the power system. This device is an acoustic receiver tuned to the ultrasonic range of 40 KHz allowing you to hear the ultrasonic noise generated by the corona discharge and arcing connections that generate the power line static on your radio. Using an 18-inch diameter plastic dish giving a narrow beamwidth to pin point noise sources to less than 12 inches at 50 feet. The dish also has a short focal point making the overall front to back depth just seven inches. With the handle mounted close to the dish, the center of gravity is closer to the handle reducing fatigue on the hand from the weight pulling down in front. An ultrasonic transducer mounted inside a sturdy metal support helps reduce dish bending and warping. Targeting holes built into the transducer mount and on the dish are aligned with the beam of the dish allowing you to pinpoint the noise sources on the pole. Receiving electronics are mounted on the handle for convenient operation. Operates on a standard 9-Volt battery (not included). The gain of the receiver is such that you can receive noise generated from power line sources from several hundred feet away. A 3.5mm headphone jack lets you use any stereo or mono headphones. Not only can you use the MFJ-5008 to find power line noise sources, you can also listen to a wide range of nature sounds! In the ultrasonic range bats, birds, and insects can easily be heard. MFJ-5008 can give you a whole new perspective on the wildlife around you. It can also help locate mechanical noise sources in the ultrasonic range. Measures 20 1/2W x 19 1/2H x 7D inches. Weighs just 2.5 pounds.