Last week, I was chatting on 30m with N3HE and I happened to mention that there seemed to be some weird QRM down around 10.117 MHz. He says, “I’ll go take a look and be right back.” So, off he goes. When he does come back, he explains that he is part of the IARU Monitoring System, and that he’s always on the alert for intruders into the ham bands.
Although he didn’t have much to say about the QRM I’d heard, I asked him to tell me more about the IARU Monitoring System. He pointed me to the IARU Intruder Watch website. According to the website:
The Monitoring System (MS or intruder watch) of the International Amateur Radio Union (IARU) is dedicated to identifying and removing all non-Amateur radio stations from those Amateur bands which are allocated exclusively to the Amateur and Amateur-Satellite Services by the International Telecommunications Union (ITU). Stations which violate these frequency allocations are called intruders. The work of the IARU MS is carried out by volunteer Amateur Radio monitors all over the world, working for their national Amateur Radio societies and co-ordinated by the IARU MS in each of the three ITU regions of the world.
The website is very informative. It has pages devoted to describing the work of the Monitoring System, copies of the system’s newsletters, and several pages of “technical stuff.” These pages go into some detail as to how to identify a signal and how to accurately measure its frequency.
There is also quite a bit of information as to how to use a spectrum analyzer to identify an intruder. This section includes a page, describing eight computer-based audio spectrum analyzers you can use to identify the type of modulation an intruding signal is using as well as other characteristics, such as power supply hum and radio frequency drift, which will help you identify an intruder.
This is a part of amateur radio that I’d never heard of before and that I think deserves more publicity. We are almost all familiar with the mess that the 10m band is becoming. We certainly wouldn’t want that to happen on the other bands as well.