On 3/4/2013 1257, Jim Brown wrote:
... it MIGHT be sufficiently suppressed by a 4 - 6 or so 1-inch long
#43 cores on each cable connected to it, and to the other end of
Ethernet cables connected to it. That won't help, of course, with
stuff radiated by the box itself.
When thinking about problems like this, it helps to think about HOW
MUCH suppression is needed. Those cores aren't going to get you 40 dB,
but they might get you 10-20 dB, and that might be enough. ;;;
Some 14 years ago, IIRC, I was sent to Elmhurst IL on an EMI complaint;
a pairgain unit* there was interfering with a local Ham on 2 meters.
Without getting into too much detail, the source was a 1.024 MHz clock
and fixable by one of two simple methods, one of which was already
entering production.
* Example: http://www.charlesindustries.com/images/i_te_dualine2.gif
Of interest to this thread:
The (non-Ham) engineer who'd gone there before me had left (in all)
forty-two clamp on 1X1.5 inch ferrites on the line and loop wiring,
which made, so far as I could tell with a spectrum analyzer and
bi-conical antenna, *perhaps* ONE dB difference.
FAR better to fix it on the board.
Cortland
KA5S
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