QRM Eliminator Black 1.8 MHz‑30MHz X Phase Eliminators Adjustable Signal Canceller 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.