My clock radio is virtually useless at night lately in the 500-800 KHz range due to extreme static noise over the stations' broadcast. However, by accident I discovered that the noise virtually disappears when I turn and leave on the light in the walk-in closet. Any idea what might be causing this and how to fix it?
Any poor connection can make minute arcing. You notice it at night on AM stations since most of them must reduce transmitted power at (local) sundown., so your radio AGC's gain goes up to compensate, making it also more sensitive to electrical "static". ...Jim Thompson
| James E.Thompson | mens |
| Analog Innovations | et |
I experienced a similar situation several years ago. It turned out that one of the lighting circuit breakers in my service entrance was causing the noise. Simply opening then closing said breaker solved the problem. There were no active loads on that circuit. Go figure.
You said "vitually disappears". Does that mean that it's still somewhat audible when the light is turned off?
Check the following with a portable AM radio for EMI:
Arcing conventional wall switch
Arcing circuit breaker
However, if it doesn't completely go away when the power it turned off, I would go hunting for switching type wall warts (power supplies and chargers). The Chinese cheap clone variety produce large amounts of RF noise. Almost anything with a switching power supply inside (which is just about anything electronic these days) should be tested.
Also, to be sure that it's actually coming from your house, turn off the power to the entire house at the breaker panel. If the noise is still there, then it's coming from the neighbors (or the alien invaders).
Jeff Liebermann firstname.lastname@example.org
150 Felker St #D http://www.LearnByDestroying.com
You might try a small portable AM radio to sniff around and locate high noi se places. I have the same problem and traced it to my desktop computer whi ch was turned off. Don't know what's wrong with it, but the noise goes away when I disconnect the power plug. It doesn't have a hard power switch, so I have to pull the power plug out of the computer.
I have the same problem and traced it to my desktop computer
Many desktop computers stay partially on all the time, so that they can do "wakeup from LAN", ie. turn on when a message comes in to the Ethernet port. Some have a yellow LED on the motherboard that stays lit to indicate standby power is on. The network jack lights may still light up, too.