Recently I was working in my home office when my wireless keyboard started playing up and dropping random keystrokes. The wireless mouse on the other hand worked perfectly. Of course the first thing that comes to mind is to check the strength of the keyboard battery. According to the Windows control panel it was good. Strange. Even checked them with a volt meter (one of the benefits of being trained as an electrical engineer) - the battery was good.
Must be a faulty transmitter in the keyboard. So I bought another of the identical model. Strange - the problem was still there. Tried different combinations of new and old keyboards and receiver units - they all behaved the same way; and each time the mouse worked fine. What was even stranger was when I moved the receiver closer to the keyboard, all keyboards worked perfectly. Again, behavior was identical with the new and existing keyboards.
The I noticed my cordless phone on my desk had moved to within a few inches of the original site of the keyboard / mouse receiver unit. Even though they were operating on different frequencies, the output from the phone was strong enough to sometime scramble signals from the keyboard. I also realized it was doing the same thing to the mouse, but that was masked by the fact that you don't notice a small amount of dropped data from the mouse. All it means is the mouse sensitivity goes down slightly (i.e. you must move it further than before for the same on screen effect.)
To solve the problem, I moved the cordless phone back to it's original location, and everything worked fine. Didn't even need the new keyboard. Like many problems, this one is so obvious when it is explained, but can be quite difficult to resolve. I shared it in the hope that somebody else can avoid the same pain.
By the way, if you use a wireless keyboard, you need to be aware of the security risk. It is possible for someone with sensitive equipment to pick up the signals from some distance away. Potentially they could grab your passwords off the air. I have no idea of the encryption used on the link between the keyboard and receiver unit, but doubt that it is "industrial strength". If somebody has the equipment to get the signals, they probably have the skill to crack the encryption. Just be aware of this risk. It may be enough to make you decide to go back to a wired keyboard.
