[RFI] House Ground

[Robert Nobis]

Cortland,

The MacMini is the also double insulated, although it has an internal power supply. More and more computer manufacturers are doing this.  However, it is not totally clear to me how one could realistically insulate (or isolate) the various I/O lines from such computers. For example USB ports or audio in/out lines. 

73,


Bob Nobis - N7RJN
n7rjn at nobis.net


> On Mar 16, 2016, at 09:13, Cortland Richmond <ka5s at earthlink.net> wrote:
> 
> On 3/16/2016 2:24 AM, Robert Nobis wrote:
>> Many modern, small profile, PCs have a built in power supply (switching) and are connected to the AC mains with a two wire cord/plug, without a “green wire”. My iMac and MacMini are like this as is my Microsoft Surface Pro 3.   Per your step two, should these types of computers also be bonded to the radio with a heavy short braid?
> 
> See https://en.wikipedia.org/wiki/Appliance_classes#Class_II
> 
> My Surface Pro uses a double insulated, external power supply with a number of agency safety marks. Bypassing double insulation with an external ground wire is a bad idea, as that protection is also bypassed. It can also increase radio interference.  Does this mean we can't filter signals going into and out of such equipment? No it doesn't. We have to ensure that the signals we want to filter are also insulated to the same degree as the equipment is.
> 
> Cortland Richmond
> KA5S
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