Feature: 1. Aluminum Shell: The eliminator adopts aluminum shell, and the front and rear baffles are epoxy glass fiber board FR4, which is durable. 2. PTT Control: The box has a built in PTT control, which can maintain the connection of the canceller during transmission. 3. Easy to Use: The QRM canceller is inserted into the feeder of the antenna without any other modifications to the radio. 4. Knob Adjust Phase: A silencer with a dial and knob pointer, you can adjust the phase through the knob. 5. Complete Innovation: Based on the concept of complete innovation, the canceller is incomparable to the performance of ordinary "silencers". Specification: Item Type: QRM Eliminator Shell Material: Aluminum Front and Rear Baffles Material: Epoxy Glass Fiber Board FR4 Colour: Black Frequency Range: 1.8 MHz-30 MHz Size: Approx. 120 x 95 x 45mm / 4.7 x 3.7 x 1.8in Connection: 3xBNC is used for main antenna, auxiliary antenna. RCA Jack for PTT Power Interface Size: Approx. 5.5 x 2.1 mm / 0.2 x 0.1in Power Supply Power Required: 13.8V 150mA Product Description: Connect: Transmit the Antenna to "MAIN" The auxiliary antenna is "AUX" Almost all antennas are available, and the local QRM can be received with a bad antenna. You can use another HF antenna, or even a 2m antenna, to connect only the center pin or a few meters of wire behind the shelf of the shed. When the GAIN1 knob is turned fully counterclockwise, the best result can be obtained when the noise signal level on the two antennas is the same, if not, try to change move the second antenna. To test the signal, simply connect each antenna directly to the radio, and then insert the QRM Eliminator.. Package List: 1 x Eliminator1 x Power Cable1 x English User Manual Note: There is a 0.5‑1mm deviation between the dial and the knob pointer