[Elecraft] RFI/EMI and dealing with it

[Eduardo González]

Hi Joshua.
I suggest using EMI/RFI filters in a box. For example, Corcom 10VR1
into a metallic box with male and female AC outlets to connect AC
power of PCs, Laptop, etc. Preferably, the length of power cord from
box to equipment must be short as possible.

Edu YV4GMJ

On Wed, Feb 25, 2015 at 10:46 AM, Ken <wa8jxm at gmail.com> wrote:
> Switching power supplies can generate a lot of RFI if not properly designed and filtered (can you say “lowest cost chinese bidder"?).   The little wall-warts are often switching supplies and often poorly filtered.  If they are your problem (easy to tell by unplugging them), you can replace them with better warts, or, if they are 12v, run them off of your main 12v supply.
>
> Ferrite beads might help, I would place them close to the wart itself.
>
> One of the best ways to tell if the noise is from inside your house is to run the rig off of battery power and throw the main breakers.   If the noise drops, then you can hunt within your own domain.   But if the noise remains, then it is external to your home.
>
> I’ve done the battery op trick here and the noise did not change, it’s incoming on the power line.
>
> Ken WA8JXM
>
>
>> On Feb 25, 2015, at 10:00 AM, Joshua Gould <jg.k8wxa at gmail.com> wrote:
>>
>> Greetings,
>>
>> I am the relatively new owner of a KX3 and I've discovered somewhat of a
>> problem:  The switching power supplies that supply power to at least my
>> laptop, an external display, the router, the desk lamp and possibly my
>> speakers create S5-7 noise on all bands and S9 noise on some of them.
>>
>> I unplugged the power cable that controls the desk and the noise dropped to
>> an S1-2.  I plugged the main power cord back in and then started by
>> unplugging individual items, keeping track of what I was plugging in and
>> what the noise level was like.
>>
>> I placed an order on Amazon for some snap on ferrite beads and they should
>> be here  today. Having never had to track down the source of noise like
>> this, I am unsure of where to place the beads to have the maximum effect to
>> clear up the signals so I can enjoy operating from home...
>>
>> I'll add that I first noticed the high amounts of noise after I had strung
>> up a wire inside the office because something had happened to my G5RV on
>> the roof.  I am suspecting bad coax on the G5RV as I have it working by
>> playing with the coax.  Neither of the PL-259s on my Comet CTC-50 window
>> passthrough jumper (Landlord and XYL say no holes in the house.. :() are
>> tightened down and I can hear stations in the noise.  Tighten them down and
>> I get silence. If I unplug the antenna from the side of the KX3, I get
>> silence (well, unless the volume is up in the 30's or higher and I have the
>> speakers connected) I can still hear noise but it doesn't register on the S
>> meter.
>>
>> If anyone could help out a still somewhat new General with this, it would
>> be appreciated.
>
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