[RFI] re: It's the old story of peeling the onion --

[Jim Brown]

On Sun, 05 Dec 2004 16:11:37 -0600, David Garnier wrote:

>1) If you have a couple of these wall-warts or external
>switching power supplies plugged into the same outlet.
>Rule #1: "Broad-band noise (BB) is usually additive."
>
>2) The wall-warts & switching power supplies (that I
>have taken apart) are NOT internally encased in a metal
>box! Given that fact, do not lay them over nearly cables.
>Rule #2: "You will (take your pick) magnetically or capacitively
>coupling the EMI (BB) energy unto other cables or your
>metal desk top!
>
>3) I like the idea of getting rid of these switching supplies
>and using an external linear supply, but you need to filter
>the digital noise before you connect it to the linear supply.
>
>4) We have discovered at work that the plastic clamp on
>EMI ferrite beads (FB), the plastic soon fatigues and the
>ferrite halves don't make connection anymore!  Solution
>is to place a Tyrap on each ferrite bead.
>
>5) If all else fails, don't operate on multiples of crystal
>harmonics!!!  This is a well known problem within the EME
>moon bounce community (due to antenna & preamp gain.)

Thanks for all of this excellent advice, and I can't find fault with any of 
it. It's part of the next layer of the onion in my shack. But I suspect 
that after taking care of my own dirty laundry, I'll need to move out 
into the neighborhood. 

Jim Brown  K9YC