Feature: *1: Simple, efficient, beautiful and elegant appearance *2: Frequency bandwidth, high sensitivity, 100KHz-1000MHz (400-470Mz with antenna, please use antennas of different frequencies to test signals of different frequencies to obtain better results and sensitivity) 3: Pointer amplitude is adjustable (protect the instrument) *4: Built-in automatic damping function, that is, buffering function, to prevent the pointer from swinging too fast and causing damage. *5: Small size, easy to carry, size: 90*115*70mm (excluding raised antenna part) *6: Test sensitivity: 0.1w transmitter distance 0.1-1 meter 2W/5W transmitter, 1-3 meters range. The range of 10W transmitter is 2-5 meters. 50W is about 3-10 meters. *Use HP8921A comprehensive radio tester, the sensitivity is -20dbm, -2dbm is enough. (The video bit rate is different, and the sensitivity will be different) Specification: Instructions for use: Please turn the "amplitude adjustment" to the far left before use. The length of the pull antenna depends on the frequency of the test. It is better to have 1/4 wave as much as possible. The handheld radio is approximately 1 meter away from the field strength meter. Don't get too close! To prevent the signal from being too strong and burning the field strength meter! Then press the PTT button of the walkie-talkie to put the walkie-talkie into the transmitting state. At this time, the pointer of the field strength meter should indicate a signal. The stronger the signal, the bigger the indication! Amplitude adjustment: If the field strength indicator indicates the maximum range, you can adjust the "amplitude adjustment" so that the pointer indicates the appropriate position. Antenna Maximum Gain Point Test Method 1. In order to change the frequency conveniently and quickly, the keypad should be used to manually set the frequency of the intercom. 2. Connect the walkie-talkie to the antenna feeder, place the field strength meter near the antenna (depending on the environment), and try to place it within the vertical radiation angle of the antenna. The antenna planning method is the best. 3. Set the frequency of the intercom, press the transmit button, observe the meter reading, and register the meter reading. Then set the intercom to another frequency point, let the intercom enter the transmitting state again, observe the meter reading...and then compare the readings at each frequency point! You can know the best frequency/band for the antenna under test! Package Included: 1 x field strength indicator 1 x antenna Note: 1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness. 2. Please allow slight manual measurement deviation for the data. 【Utility and value】If a product is useful to you, it has value when we sell it. 【 Shopping cart 】 Buy multiple pieces at a time, the more affordable the price. 【 Good quality】Made of high-quality material, ensuring durability and practicality in usage. 【 After-sales service 】 Provide 48-hour after-sales service to quickly answer your questions.