Why Ferrite Cores with HDMI Cables?

Ken Wilhelm · 01-13-07, 11:45 PM

I need a 25 ft HDMI cable to go from my DISH 622 and HDTV. Monoprice has them with or without FERRITE CORES. What's the difference?

kenglish · 01-14-07, 09:43 AM

They keep the square-wave data signals from leaking RF spectrum energy all over the place. Square waves have almost infinite noise bandwidth, and will cause interference to all your nearby radios and TVs.

A lack of ferrites might indicate that they have sufficient shielding to prevent interference, or that they are "clean" enough to meet some FCC Part-15 specs (but, could still interfere to some extent), but I wouldn't trust it. Ferrites are pretty cheap to make, anyway....good insurance.

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Ken Wilhelm Member Join Date: Jun 2000 Location: Olympia,WA usa Posts: 61	Why Ferrite Cores with HDMI Cables? I need a 25 ft HDMI cable to go from my DISH 622 and HDTV. Monoprice has them with or without FERRITE CORES. What's the difference?

01-14-07, 09:43 AM	#2 \| Link
kenglish AVS Special Member Join Date: Jan 2000 Location: Salt Lake City, UT, USA Posts: 3,788	They keep the square-wave data signals from leaking RF spectrum energy all over the place. Square waves have almost infinite noise bandwidth, and will cause interference to all your nearby radios and TVs. A lack of ferrites might indicate that they have sufficient shielding to prevent interference, or that they are "clean" enough to meet some FCC Part-15 specs (but, could still interfere to some extent), but I wouldn't trust it. Ferrites are pretty cheap to make, anyway....good insurance. __________________ Ken English, Sr. Engineer, KSL-TV/-DT. "Not a REAL Engineer, but I play one in TV"