I just figured out why I have interference on my "boom box" radio. I unplugged my cordless phone, and it went away. I tested it on two jacks, within 3 feet of one another, and the same thing applied. However, I then plugged in the phone to another jack in another part of the house, and it did not interfere. (course, there is no phone jack there, so it did me no good.
Why is this?? And, will I be forced to moving my radio?? I do not want to.
Thanks Patti
snipped-for-privacy@yahoo.com hath wroth:
There's probably a switching power supply in the cordless phone base or inside the wall wart. The RFI (radio frequency interference) is being conducted down the power lines to your radio. Most houses have two phases on the AC power system. If you plug it into an outlet that's on the other phase, it will probably not pickup the RFI as badly. You can probably eliminate the problem with either a clamp on ferrite bead, or a replacement wall wart power supply.
-- Jeff Liebermann jeffl@comix.santa-cruz.ca.us 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Jeff nailed this on the head. HE must be an EMC engineer.
H. R. Hofmann
snipped-for-privacy@att.net hath wroth:
Nope. They didn't have EMC engineers when I was doing RF design. Regulatory oversight and compliance testing was minimal. My trick is that if you understand how the stuff works, you can figure out what's wrong fairly easily.
-- Jeff Liebermann jeffl@comix.santa-cruz.ca.us 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Single phase, tapped secondary.........
As a past president and Life member of the IEEE EMC Sociiety, we are always looking for new recruits, no matter what their background. I did telco central office swiching equipment design and fell into EMC when I discovered the source of noise coming from one of our first electronic switching systems was an unbalanced bus about 200 feet long that interconnected about 40 frames. Going to a balanced bus solved the problem and I was called an expert on that one small effort. 20 years later I was president of the EMC Society, after some other reasonable efforts in the EMC field. It is always good to find someone who really understands how things work.
H. R. (Bob) Hofmann
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