Anecdote: I was once called to a Ham EMI complaint involving one of my
then-employers pole and wire-mounted subscriber equipments; a harmonic
of its 1.024 MHz clock was interfering with a 2 meter repeater the
Amateur wanted to hear. A predecessor had left *42* ferrites on the
inputs and subscriber drops, which MIGHT have made *1dB* improvement.
Back in the lab, I was able to knock it down by adding a (IIRC 39 Ohm)
resistor to the clock line on the legacy single-sided board.
On 8/24/2013 1305, Charlie Gallo wrote:
I've come up with a new rule of thumb:
If the manufacturer puts a ferrite on the leads of a device, it isn't enough,
and the item is an RFI bomb
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