I have a Macbook Pro sitting next to my Elecraft K3. I have a USB cable going
from the Macbook to the KAT500 tuner and found that I was getting RFI from the
cable at various points on 20m. I stuck 3 snap-on ferrites on the USB cable by
the connector to the Macbook and that took care of it, however it did make me
wonder if I should be bonding to computer. It’s not clear how, however because
there’s no easy connection to the chassis.
David
NY6W
> On Mar 16, 2016, at 10:01 AM, dalej <dj2001x@comcast.net> wrote:
>
> I have two iMacs, same deal with the PS. I don't have any noise from either
> one. My neighbors plasma TV I hear though.
>
> All the Apple products I've owned since 1988 never had an issue with RFI from
> any of them.
>
> Dale, k9vuj
>
>
>
> On 16, Mar 2016, at 11:55, Robert Nobis <n7rjn@nobis.net> wrote:
>
> 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@nobis.net
>
>
>> On Mar 16, 2016, at 09:13, Cortland Richmond <ka5s@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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>
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