Item Type: QRM Eliminator_x000D_ Shell Material: Aluminum _x000D_ Front and Rear Baffles Material: Epoxy Glass Fiber Board FR4_x000D_ Colour: Black_x000D_ Frequency Range: 1.8 MHz-30 MHz_x000D_ Size: Approx. 120 x 95 x 45mm / 4.7 x 3.7 x 1.8in_x000D_ Connection: 3xBNC is used for main antenna, auxiliary antenna._x000D_ RCA Jack for PTT_x000D_ Power Interface Size: Approx. 5.5 x 2.1 mm / 0.2 x 0.1in Power Supply_x000D_ Power Required: 13.8V 150mA_x000D_ Product Description: _x000D_ Connect: _x000D_ Transmit the Antenna to "MAIN"_x000D_ The auxiliary antenna is "AUX"_x000D_ 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.