Features 1.WIDELY COMPATIBLE: Adjustable signal canceller contains the interface circuitry needed to work with most modern HF transceivers and is widely available. 2.EASY TO USE: X Phase QRM eliminator is easy to use and plugs into the antenna feedline from the receiver unit without any other modifications to the radio. 3.ADJUSTABLE: QRM eliminator now allows phase angle and amplification to be adjusted to eliminate unwanted signals before they get to the front of the receiver. 4.AUXILIARY ANTENNA: An additional auxiliary receiving antenna is required, such as a 2m/6.6ft antenna or a few meters of wire in a shed. These two antennas receive unwanted signals, resulting in different phases. 5.BUILT IN PTT CONTROL: Aluminum alloy QRM eliminator has a built in PTT control that keeps the eliminator connected during transmission. specificationItem Type: QRM Eliminator Material: Aluminum Alloy Frequency Range: 1.8 MHz-30 MHz Connection: Main Antenna, Auxiliary Antenna And 3xBNC For: RCA Jack For PTT Required Voltage: 13.8V 150mA PackageList1 x QRMEliminator 3 x Antenna Adapter 3 x Knob Accessory 1 x Antenna Cable 1 x RCA Cable 1 x Power Cord 1 x Instruction Manual