View Single Post
  #7   Report Post  
Old April 30th 08, 04:21 AM posted to rec.radio.amateur.homebrew,sci.electronics.design
Phil Allison Phil Allison is offline
external usenet poster
 
First recorded activity by RadioBanter: Apr 2008
Posts: 18
Default Help, Laptop causes FM interference


"amdx"
"Phil Allison"
"Charles"

Switch-mode power supplies are dirty ... lots of harmonic energy. The
interference is both radiated and sent back into the ac mains.



** But they don't usually generate energy in the FM broadcast band (
i.e. 88 - 108 MHz) - that is more likely to be due to the CPU and
associated high speed circuits inside the PC.

Good call Phil,
Maybe I didn't say it clearly, but just plugging the ac cord in and
holding
it near the laptop induces noise on the power line. ( ac cord only, no
switching power supply attached)


** Validates my comment completely.



.... Phil