You have received some good tips. I would like to add that in a previous
life when I was a lead tempest engineer I had to design and test items
like keyboards and the problems we had to overcome, in some cases, are
somewhat similar to what you are experiencing. Of course the major
difference was which direction the offending RF was flowing.
Adding the proper ferrite cores, with multiple turns thru each end on
the main cable is a great place to start since it is easy, inexpensive
and does not involve ripping open the KB. Replacing the cable with a
properly shielded one and ensuring that it is properly terminated is
beyond what most people are prepared to tackle.
Just keep in mind that a typical stock, plastic cased keyboard will not
impede much RF energy from getting directly into the PCB traces, the
electronics on the PCB, and all the cables/wires inside the KB itself.
All of these become receiving antennas & receptors of the RF you are
transmitting. The same is true of RF energy escaping the KB leading to
possible RF issues which was my task to solve. I suspect a pair of
proper cores will help you out but in the event it does solve your issue
keep in mind the other possibility I mentioned above, i.e., direct
impregnation of RF directly through the case and into the KB itself. GL
es 73
Gedas, W8BYA
Gallery at http://w8bya.com
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
On 3/3/2018 10:24 AM, Joe wrote:
Is RF getting into a keyboard issue OK here, it is RFI in a way..
OK, Say you get RF into a USB keyboard. It just stops working and the
only way to get it working again is a total re-boot.
I'm assuming the best option is ferrite beads on the cable.
Now question, where is the best placement of the beads. Keyboard end?
Computer end? BOTH?
I have two here, a small one where I could get one or two passes
through the hole. ( it is a Radio Shack split thing )
and then a much larger one, also split,, but the hole is close to a
inch ID. so I could do many turns.
What would be best to put where?
Joe WB9SBD
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