[RFI] Samsung refrigerator RFI

Tom Thompson tlthompson at qwest.net
Wed Aug 8 17:20:42 PDT 2012

Hi Kelly,

My approach has been that I might help them fix the problem since they 
are broadcasting their grow.  I was able to talk one grower into letting 
me borrow his light and ballast during the day since he only had the 
light on during the night.  I set it up in the basement and experimented 
with several common mode choke designs.  The best solution was a common 
mode choke on the lamp side WITH THE GROUND WIRE PASSING ON THE OUTSIDE 
OF THE CHOKE.  This choke was placed close to the ballast.  Larry, W0QE, 
published the results on his web site.  See 
On my mobile receiver, sitting in front of the grower's house, I saw the 
noise drop from 40 dB over S-9 to S-5 when the filter was in place.  At 
my house which was a block and a half away the noise is no longer 
heard.  Most of the lines going from the ballast to the lamp are close 
to a quarter wavelength on 40 meters so that is where the noise peaks.  
The ballast switching frequency is around 70 kHz. The harmonic content 
drops off as the frequency increases but the antenna factor gets 
better.  I think 40 meters is about the cross over point.

Be careful approaching these folks.  If the house is a rental, you can 
get the landlord information from the public tax records.  One landlord 
sent me a $40 gift certificate for alerting her of the grow.  She 
evicted them but not before they did $4000 worth of damage to her 
property.  If medical marijuana is not legal in you state (it is here in 
Colorado) you might be able to get the police to accompany you.

I hope this helps.

73,   Tom   W0IVJ

On 8/8/2012 5:55 PM, Kelly Johnson wrote:
> How did you deal with the grow lights.  I have a grow house near me
> with grow lights that kill HF 12 hours per day.  I've been too afraid
> to go complain to them.  They're shady characters and they aren't
> growing vegetables.
> On Wed, Aug 8, 2012 at 4:53 PM, Tom Thompson <tlthompson at qwest.net> wrote:
>> I would, at the very least, file a report with the FCC.  This device is
>> most likely not compliant with the conducted emissions requirements.
>> Fixing these devices one at a time is getting really old.  In my
>> neighborhood alone I have dealt with 5 grow lights, 3 halogen lights,
>> and one surveillance camera.  All have been Chinese imports.
>> Tom   W0IVJ
>> On 8/8/2012 3:13 PM, Mel Crichton wrote:
>>> My wife was so proud of herself when she bought a new Samsung side by side
>>> refrigerator with energy saving compressor. Yes, it runs quiet and doesn't
>>> use much juice, but the compressor drive has a 5 KHz supply, and as luck
>>> would have it, it wipes out all the HF bands every 5 KHz. To make matters
>>> worse, beside the 5 KHz birdie there's serious hash between the birdies. If
>>> I want to operate, I kill the breaker to the refrigerator. This isn't doing
>>> the fridge any good. I threatened to return the fridge but she threatened
>>> other things. I may find a way to make it self-destruct.
>>> I called Samsung  USA and they kept me on the phone for a half hour looking
>>> for any tech support inside Samsung USA who might know of a fix. (My guess
>>> is, inadequate shielding and probably a square wave generator). No dice....
>>> they are not aware of this problem.
>>> Any help out there? The warranty isn't expired yet, but I will be removing
>>> screws in the next few days. I may get lucky with some simple shielding
>>> (Already wrapped the AC cord in ferrites)
>>> In the meantime, BEWARE of Samsung energy saving refrigerators. If you are
>>> considering any top-end refrigerator, take a portable radio  with you to the
>>> appliance store and make them turn the unit on to full cooling.
>>> Mel KJ9C
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