标签: wireless signal

Note: This story is brought to us from Ricardo Motta, who saw an earlier How it used to be column on PDP and VAX/VMS Systems and decided to share his experiences. There was a slight problem, however, in that Ricardo's tale occurred only a few years ago, while our How It Was s tories tend to be from deep in the mists of time (circa when I was young and dinosaurs ruled the Earth). But Ricardo's story was so interesting that I decided to use it as the basis for a new mini-series on interesting problems and how you solved them (I have some stories...) Hi Max. Good to write to you. I'm your fan (Britties are so smart and cool), I am 46 years old and saw some DEC VAX out there. Well, following your request "If anyone else has remembrances in this arena, please email me..." here it is. This is one of many cases we can face every day. Maybe not. Let's see. There was a time when we had a line of wireless industrial products (in fact there is a pending patent here in my actual company) used for data collecting. Five years ago, some client, an American weld wire manufacturing, bought a set of those equipments, then me and my best sixty years-old friend went there to install them. It is a pleasure for me to understand customers' needs, find a solution, develop a product, test and install, train operators, technical and management people, a whole cycle that repeats time after time, and I am so proud and grateful what I do. It was Sunday, a window in the production line (7x24). We made all the infra, tested and everything was fine. Until next Tuesday one of our guy from software made a call telling that something was wrong with the communication: mostly of the wireless packets 'were not crossing the air'. It was very strange. We double checked all nuts and bolts but none to discover. This guy realised or suspected that some equipment there was interfering with the wireless signal. It is 2.4GHz and the waves should circumvent obstacles. Or not? What happened between Sunday and Tuesday? I went there next day and we started to understand what went bad. After some more tests, we discovered that... true, the signal was losing its ways. I tried to adjust RF power: worse. Adjust the position, azimuth, nothing. The production line was running, wildly, noisily and dirty. Hey, yes, dirty. I asked the operator what was the meaning of all that grey mess, and he told me that was graphite used to grease the weld wire in some steps. Oh, no. Graphite particles suspend in the air! Graphite and wireless signal do not match, and were trying to cross some 300ft. No way. When we installed and the production line was off it was OK, but when it is on, no; no good. Then I reinstalled the antenna in a position 100ft away trying to escape the graphite grime and... and... success... It worked after all!