Good midday, 184.108.40.206.
Today is sunday the 30th of April 2017. The time is 10:59:26 and it's week number 17.
(2011-05-18) A lesson in troubleshooting
Troubleshooting and investigation have a lot in common, and I touched the subject a few months ago in a story called “The power of inference”. Now, here’s a true story that is not really related to IT, but that I think you might find interesting.
About a month ago, I got my HAM (Amateur radio) license. But my interest in radio began much earlier, when my grandfather showed me how to operate one of his old radios. It was a large “National HRO sixty” shortwave receiver that had previously been installed in the Bromma airport control tower in Stockholm. If you wanted to change which wavelength band you wanted to listen to, you had to physically remove a cassette and switch it for another cassette that held the necessary circuits to allow the radio to receive that particular band. My grandfather had worked for many years for the Swedish telecom- and radio authority “Telegrafverket” (Later Telia) and was himself a radio amateur.
All radio amateurs get a unique call sign assigned to them by their country registrar when they take and pass the exam(-s) required to operate as a radio amateur. When I finally was about to get my own license, I decided to find my grandfather’s call sign. He became a silent key in 1994. In amateur radio slang a radio amateur that has died becomes known as a “silent key”. This goes back to the days when you used a telegraph key to transmit Morse code. So my grandfather is now known to the amateur radio (“HAM”) community as SM0HAE (SK). Simplified: SM is Sweden’s country code (SA – SM actually). 0 stands for the Stockholm area. This is where the operator has his home but he can off course broadcast from another location, although this has to be noted by him during the broadcast. HAE is the part uniquely identifies the operator. (SK) means that the operator is no longer among the living. Well, on with the story…
I was able to find his information through a service called HamCall Net and that could have been the end of the story. But it wasn’t. As this information was quite old, it had most likely not been registered through the Internet. One interesting thing was that his “QTH” or broadcast location was noted along with the rest of the information. I fed the latitude and longitude into Google maps and ended up… nowhere. The map centered on some trees on the side of the road, a few miles away from a small town called Perstorp. It just didn’t make sense. Then the troubleshooter in me awoke. I spoke to my mother and asked her about it. She was quite sure he had never had a house in our around Perstorp.
The gut feeling told me there had to be a mistake somewhere, but numbers couldn’t be totally wrong. I used Google and some other tools to quickly get the latitudes and longitudes of all locations where I knew that he had either worked or lived. The numbers were all significantly different from the Perstorp location. Then my eyes fell on the grid locator that was also present in the text.
Latitudes and longitudes are cumbersome to read or telegraph over the radio, so most radio amateurs use a shorthand notation of their location. This is called a “Maidenhead locator” or “Grid locator” and it’s not nearly as precise as the latitude/longitude system. If my theory was correct, the correct location had to be nearby and my mother provided me with the final piece of the puzzle. She pointed out that my grandfather had worked at large broadcast facility in Hörby, which was fairly close to Perstorp. I calculated the locator for Hörby and compared it to the one pointing to odd location near Perstorp and sure enough:
The Stockholm location of his home was very different but the Hörby one differed with just one single character. That solved the mystery for me. Had this been a criminal investigation or some serious research done by an honest journalist, it would have been just a lead to follow. But I felt no need to check any further. This was just a fun little “mind game” that took 15 minutes and proved that you don’t have to go to great lengths to solve a “mystery”.
There are a few lessons to be learnt here:
1) Get the setting.
I knew that we were talking about broadcasting locations, so antennas had to be involved. And antennas are generally located where a person works or lives. You can’t just put an antenna up on any building and expect it to not be taken down.
2) Get the information – but not all of it
You collect enough information, you get a haystack that may or may not contain a needle. Ask yourself if the information HELPS your investigation or not. Be ready to go back to the sources if you end up in a dead end. When you work with computers it means: please SAVE the logs and data to a secure location. Logs often get overwritten over time and data changes.
3) Have a problem? - take a break
Your brains get locked in a rut after a while. When you just can’t seem to solve a problem, taking a break for a few minutes, hours or for a day gives you new insights. Remember to avoid thinking about the problem during the break.
4) Talk to others
It was my mother that gave me the final piece of the puzzle. Had she not told me that he had worked at the Hörby transmitter; I would probably been unsuccessful in finding the explanation to the weird location.
5) Put yourself in their position
I envisioned someone typing the information into a computer after reading it from a piece of paper. One small typo or unclear handwriting is all you need to get it wrong. But I didn’t expect more than one or two incorrect characters, and I was right.
There is more than this to troubleshooting. As a matter of fact, I’ve mostly covered the information gathering/investigation phase of the troubleshooting process. But still, it matters a lot how you get and analyze information.
Good luck! SA0BTZ signing off...
Posted: 2011-05-18 by Erik Zalitis
Changed: 2011-05-18 by Erik Zalitis