I am Tarif R. Santo, Call Sign: S21ON (Sierra 21 Oscar November) from Dhaka, Bangladesh. I am an amateur astronomer and amateur radio enthusiast. Here, I write about my experiments which include Astronomy, Physics, Electronics, Amateur radio, Programming etc. I post my photographs and other hobby activities. I hope you all enjoy my experiments and I will be happy if any of these contents encourage you to start a new exciting hobby.