Chapter 4: Discussion
4.1 Key Findings
Each system collected a different type of lightning data, but the data was combined to obtain reliable results. The solar e-field system captured radio signals emitted by lightning in the 0 kHz to 30 kHz range, while the lightning e-field system captured radio signals given off by lightning in the 0 kHz to 10 kHz range. The lightning visual system captured video clips of lightning flashes, confirming that a storm did indeed take place.
4.2 Evaluation of Engineering Goals
Although each independent system functioned properly, not all of the systems were functioning well concurrently. With all the systems running at the same time, we could have studied selected lightning strikes in greater detail. An actual warning system should also be developed to warn people of impending storms.
4.3 Areas for Improvement
These systems had various flaws. The square antenna of the solar e-field was designed to overcome the problems of conventional homemade square antenna, such as wires slipping off the unstable frame. However, the square antenna used in our system proved to be weak and flimsy as well, despite securing the joints of the PVC pipe with electrical tape. The redesigned frame prevented wires from slipping off, although it was easily damaged. To improve on this design, the PVC pipes could be drilled in place and strong sealants or glue could be applied at joints with additional layers of tape with stronger adhesive properties. A stronger frame might improve portability of the antenna. The frame we designed was fragile and needed to be well taken care of when it was moved from place to place. When connecting the coaxial cable to the electrical wires and 3.5mm male connector wires, we discovered the wires that made up the metallic shield did not bond with solder even after repeated cleaning of the wire to remove oil. This was because the wires of the metallic shield were made up of steel, instead of copper. A terminal block was used to connect the different types of wires together instead. This presented another problem. As the metallic shield was made up of many strands of wires, the combined were relatively thick, causing the wires to shift a lot. Although electrical tape was used to secure the wires, the connections were not stable. A coaxial wire with copper wires should have been used instead. The antenna was also exposed to rain and heat from the Sun, reducing the effectiveness of the adhesive tapes. This caused PVC pipes to disconnect from the PVC pipe connectors. The electrical tapes used to secure the wires in the terminal block had to be replaced regularly. A thicker electrical cable would improve the sensitivity of the antenna. Due to time constraints and availability, the wires used were rather thin, causing the data to be slightly limited. The camera used in our visual detection system had a small field of view, significantly reducing the chances of capturing lightning strikes. The UFOCapture software was left to run 24 hours a day, using up a lot of disk space. There were many recordings of birds flying past the camera, all of which we had to delete. The sensitivity could be turned down to avoid recording insignificant movements. Although results could be logged and saved in Radio Skypipe, some files could not be opened, with an error stating that the “Time index must be incremental”. This rendered some results viewable after logging and saving. Furthermore, The buddipole used in the lightning e-field was connected to the VLF radio via a coaxial cable. The connection point where the buddipole and the coaxial cable met was held together by rubber which broke off due to heat from the Sun, but we held them together with electrical tape. The jack on the VLF radio had problems too. The power cable was loose, causing the VLF radio to switch on and off by itself, affecting our data collection. Whenever the power came on, it generated static which was recorded in Radio Skypipe.