Electricity and Magnetism geeks - help me! I would like to stop the GSM interference from my iPhone to my speakers with ferrite chokes. I imagine a bit of information would help me get the best ones...
So, it has become somewhat common knowledge at this point that gsm noise
is irritating lots and lots of people. While the hack of cutting these ferrite beads out of USB cables is cute, and all, I figured I'd order just the parts I need from digikey
, where I've bought some electronics stuff in the past.
The issue is -- these little buggers come in a variety of sizes, with a variety of impedance levels and frequencies (frequencies? what?). I would link to a DigiKey search results page, but they seem to use POST in their forms, so I can't get you a URL with search results....
First of all, I'm pretty sure GSM is 850mhz with AT&T in the united states. All of the ferrite core snaps I've found on DigiKey have a "Frequency" of either 100mhz or 300mhz ... how can a little ferrite bead have a "frequency"?
Their impedance levels vary wildly -- from 35 ohms to as high as 572 ohms.
So, my question: If we know what frequency AT&T's GSM is that's causing my interference issues with my stereo speakers -- how do I choose the ferrite cores that will be most effective in stopping it? Does it even matter which ones I get?
They're all reasonably priced, ranging between about $0.95 and $2.50... and since I'm only buying maybe 6 or 8 of the things, I'm more than happy to shell out the extra bucks if it means less noise getting through.