This production is based on drawings collected online. It is said that there is a gain of about 11DB, which is true after the completion of the test. material: tool: Reference drawings: Shaping: Simple handling of mosquito coils Mounting the antenna: clever use of heat-shrinkable tubes for insulation Jiaxi fixed: 500W Digital Tv Transmitter,Wireless Digital Tv Transmitter,Digital Tv Broadband Transmitter,Digital Tv Signal Transmitter Anshan Yuexing Technology Electronics Co., LTD , https://www.yxhtfmtv.com