Is this Time Radiation at work?!!!

May 11, 2011 7:01 AM

Can cable boxes affect digital clocks?

We are experiencing an interesting phenomenon with our cable box and a digital clock that we keep next to it.

We first noticed a couple of months ago that the digital clock that we kept next to our cable box was running fast. We would reset it and within a day or two it would be running fast again. We assumed at the time that it was defective and bought another one (a different model this time).

Within a few days the new clock started running fast as well. We started to suspect that the cable box was somehow sending out "time radiation" (my term!) that was causing the clocks to speed up.

Coincidentally, we started having problems with the cable box around this same time and had to have it replaced. The new box (again, a different model from the previous one) seemed to make the clock speed up even more!

We tried blocking the space between the clock and the box, and even moved the clock to another shelf in the same unit as the box, but, to no avail. We finally moved the clock to a different part of the room as of last night, and as of this morning the clock is running fine!

Has anyone ever experienced this? Should we call the cable company? We would prefer to have the clock be next to the cable box but at this point it doesn't seem likely. Any suggestions would be appreciated. Thanks.

posted by Hanuman1960 to technology (6 answers total)

Yes. Consumer electronics are incredibly noisy devices (radio frequency-wise), and it is absolutely plausible that it is putting out some kind of noise that the digital clock is misinterpreting as a valid clock "tick".

(Because digital clocks work by listening to an oscillator. Which is a device that just "ticks" at a fixed frequency, like a tuning fork. The clock knows that X ticks = 1 second, and measures time accordingly.)
posted by gjc at 7:11 AM on May 11, 2011

If they were plugged into the same socket, subtle differences in voltage or garden-variety EM fields can have unpredictable effects on cheap clocks. Electrostatic induction is the likely cause, though Time Radiation does sound much more romantic.
posted by mhoye at 7:11 AM on May 11, 2011

I know nothing about Time Radiation, but you may be able to configure your cable box to display the time, if that would solve the problem. On ours (Time Warner Cable, Scientific American 8300 boxen) you can have it display the channel, the time, or neither.
posted by Rock Steady at 7:12 AM on May 11, 2011

Thank you gjc and mhoye! Both seem like plausible explanations! Also, Rock Steady, our cable is through Comcast and the boxes that they offer don't have a display window. That's why we were using a separate clock. Thanks anyway!
posted by Hanuman1960 at 8:48 AM on May 11, 2011

Is this clock line powered or battery powered? Line powered clocks like alarm clocks keep time by counting the 60Hz cycles of the AC power. This is a remarkably stable time source over long periods because it must be kept within tight tolerances for the electrical grid to operate. However, if another electrical device is putting noise onto the line in the form of harmonics then this will be picked up by the clock. Try getting an AC line EMI filter and see if it fixes the problem. Moving it to the other side of the room potentially put it on a different circuit (i.e. different outlet) which might offers more insulation from the EMI.
posted by Rhomboid at 8:56 AM on May 11, 2011

This isn't what you asked, but if your cable box is old they might upgrade you to a new one for free (that either has a clock or won't cause your clock issues). When my mom moved, Comcast brought a new box and modem.
posted by radioamy at 11:34 AM on May 11, 2011