Ask Mr. Answer Person: "Why did the sirens go off again in Decorah Friday?"

A number of readers have e-mailed us to ask about the sirens going off in Decorah Friday morning. Here's one typical e-mail:

I have a question which I hope you can answer on the blowing of the warning sirens at different times of the day. A couple of weeks or so ago they went off at an odd time (not their usual 6:00 p.m. time) and this morning it was 7:30 a.m. Is there a reason for this or just mechanical problems?

Mr. Answer Person will now lead you through a discussion of modern communications equipment. We now use so many mobile devices (cell phones, wireless Internet routers, etc.) that the airwaves have gotten crowded with signals. It appears that the Decorah warning siren has fallen victim to this situation--getting triggered at odd times by odd signals.

Police Chief Tom Courtney says the latest accidental siren firing came just as crews were about to install a new tower and a new receiver to take care of this problem. The new tower is on City Hall, instead of at a remote location, which should cut down on strange signals messing up the warning receiver. The new receiver is much more closely tuned, so that also ought to help.

The bottom line is that police are hoping the new equipment prevents the siren from going off when it's not supposed to!