SincereetaliFeatures: Featured as being of excellent sensitivity and accuracy, they help you find the best position for DVB-T antenna installation. Designed with a compass for easier and faster adjustment. With ring and attenuation control function, easy and user-friendly operation. The return digits indicate the signal strength intuitively. Mini size and light weight, truly portable and easy to carry. Operation: 1. Connect the antenna cable to the left of the F female and the battery pack cable to the right of the F female. Remove any external amplifier* that may be connected to the antenna. 2. Adjust the antenna to the best position by looking at the indicator reading. Higher on the scale gives a better signal. If the viewfinder reading is at full scale, adjust the level control knob to reduce the reading to about 5 (turn the control clockwise to decrease the reading), continue moving the antenna until the highest reading is obtained. 3.Remove the viewfinder and replace any unplugged amplifier. Important Note: -If your antenna has an internal amplifier, (for example: 01MM-SQ01), it must be powered by an external power source via a DC insert module. Ensure the power insert is placed between the viewfinder and the antenna. Specifications: Color: Blue Material: Plastic Frequency Range: 170-860MHz Input Level Range: 65-95dBuv Impedance: 75Ω Insertion Loss: ≤5.0dB Power Supply: 9-12V DC Item Size: Approx. 127 * 63 * 35mm / 5 * 2.48 * 1.38in Item Weight: Approx. 90g / 3.2oz Package Size: Approx. 18.6 * 14.1 * 4.3cm / 7.32 * 5.55 * 1.69in Package Weight: Approx. 197g / 6.97oz