While studying about Yagi-Uda Antenna in a boring Engineering class, I never imagined making one myself. I recently joined Karkhana to help out in their new project focusing on space exploration and DIY satellites. This year Karkhana Innovators’ Club is focusing on space exploration and DIY satellites by running three separate sessions. Through this program we intend to send two small satellites into space within 18 months and create a science based curriculum around space technology for Nepali schools.
On the very first day at Karkhana, we went shopping for some old antennas and a duplex radio. Unfortunately, we could not find any that matched our requirement. Instead, we ended up buying a TV card. After returning to Karkhana, Hasin suggested that we make our own DIY Yagi-Uda antenna and see if we catch Nepal TV or Kantipur on our computers. At first I thought he was just kidding but after realizing he was serious, I was startled. The Yagi antenna that I had once studied only for the tests and grades was going to be built by me for a real experiment.
I looked it up on the internet and found some interesting ways to build it. The most important thing while making a Yagi-Uda antenna is the dimensions of the elements. The correct length and spacing radiate the radio waves such that all arrive at the front of antenna in phase, so that they superpose and add, increasing the signal strength in the forward direction. Keeping this in mind and using online calculators, I computed the lengths and spacing of elements.
The next day Hasin and I went to buy aluminium pipes, which was another adventure, the pipes were 12 feet long, and we had to bring them holding upright on a motorbike. Luckily, we succeeded to bring the pipes without snapping any wires, typically dangling dangerously close to the road and thankfully not injuring anyone.
The antenna wasn’t very difficult to build once I got the hang of the process. For the first step, all I had to do was measure, mark and cut the pipes. The pipes could have easily been cut with a hacksaw but Sunoj suggested to use an easier and shinier new tool, which was lying at Karkhana space. So everyone in the office got excited and took their turns in using the ‘miter saw’ to cut those aluminium pipes. And within minutes, the pipes were ready to be aligned for Yagi. After drilling holes and screwing the pieces, Yagi-Uda Antenna finally took shape.
After taking a break for a day, I continued my work on the antenna again. This time, I had to make the antenna work. I had to complete the wiring and join it to the TV card to receive the signals of FM and TV. After working for a couple of hours on wiring, soldering and testing it with a TV card, signals of eight FM channels were caught.
With all the excitement I called Hasin and we checked if the signals were really caught by the antenna or not. Suddenly, Roshan quashed my excitement by receiving the FM signals by simply replacing the antenna with a piece of wire. Not being disheartened by this, we tried to catch TV signals instead with the Yagi-Uda Antenna. Luckily, we caught a very distorted signal of Kantipur channel. To make sure it wasn’t just beginners’ luck, we went outside and then to the roof to catch TV signals. With a lot of patience and hit and trial, we were finally able to catch the signal of Nepal Television and then with some more trials, Kantipur Television.
To make sure these signals were caught by the antenna, we checked it again with the wire, like for the FM and thank goodness the wires could not catch TV channels. This was how we found out the Yagi-Uda antenna actually works.
This was my first task at Karkhana, and it was successful. I am looking forward to work on more interesting projects related to space explorations and satellites. After all, who would not want to be a part of launching satellites into space.