[RFI] House Ground

[Roger (K8RI)]

I added a 3 KVA, true sin wave generator with regulated output.  I'm in 
the process of getting the two big computers (4 and 5 GHz) and the 
entire station (except the big amp) That 240 VAC circuit runs right 
along with the 30A 120VAC to the regulated supply. IOW everything is fed 
off one circuit.  The computers are in full size, steel tower cases. 
(Well shielded)  Both computers use 850W power supplies and have a 
Gigabit resident NIC There are also two servers.  All this goes through 
a smart switch, to the router.  The computers hook to the VNAs and the rigs.

I don't think I can over emphasize the need for "good" power supplies 
with dynamic power factor correction.  Many of the brand name PCs have 
supplies that must be related to wall warts.

Other than following good practice,  Using good power supplies with 
dynamic PFC, and tying everything to the SPG, I took no special 
precautions for RFI, yet have none that I've detected...so far.
HOWEVER I realize that the next time I change something, add something, 
remove something, reroute a wire...etc, the whole thing may go to pot.

If I put another computer on the network in the shop to work with that 
station, it will be wireless.  Even though I see some high speeds 
listed, I've not seen one wireless network come near the speed of my 
CAT5. I'll put up with the slower speeds for the sake of saving 
equipment/money.

73

Roger (K8RI)


On 3/16/2016 Wednesday 3:21 PM, dalej wrote:
> I got a Macbook Pro here in the shack that makes three.  If the snap on device took care of it then I wouldn't worry about trying to ground the macbook.  You might do harm to the macbook and not fix anything more than you already have.
>
> Dale, k9vuj
>
>
> On 16, Mar 2016, at 12:19, David Winarsky <david at winarsky.com> wrote:
>
> 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 at 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 at 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 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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