Hi Tom,
I'm the one that reported the 3 Samsung Plasma TV cases to Ed and the ARRL,
and in all cases the common mode chokes were the same (14 turns of a power
cord on a 2.4" OD Fair-Rite #31 mix toroid core), and you can see my most
successful case on youtube at http://sites.google.com/site/televisionrfi/
My average time for tracking down a Plasma TV generating RFI is about 10
minutes, but my most recent case has also been the most difficult.
Here is the info I sent to Ed that he just mentioned which provides more
details :
------------------------------------------------
I worked on 3 Plasma TVs generating RFI within the last year, and the
results have covered the entire spectrum so to speak. In one case 14 turns
of the TV power cord thru #31 toroid core did a great job, in the second
case 14 turns of the TV power cord reduced the signal somewhat, and in the
3rd case the toroid core on the power cord, as well as a Delta EMI line
filter (10DRCG5) had no impact (and disconnecting all other cables from the
TV had no impact).
All 3 Plasma TVs have been Samsung. The 3rd case mentioned above (the one
in which nothing worked) is 930 feet from my house and it's located below
grade (in a basement below ground). I have discussed this specific case
with the ARRL.
The model number of the 3rd case mentioned above is is as follows :
Model : PN58B650S1FXZA
Serial : AUQ53CE5400478F
Version : K301
I personally am concerned that radiation from the screen (or other parts of
the TV) may be coupling back into house wiring, etc. and that filtering at
the TV (line cord, etc.) may not totally mitigate the RFI.
------------------------------------
73,
Don (wd8dsb)
On Wed, Mar 26, 2014 at 5:24 PM, Tom Thompson <tlthompson@qwest.net> wrote:
> Ed,
>
> As you well know, all common mode chokes are not created equally. Do you
> have any details on the chokes that did and did not work?
>
> Tom W0IVJ
>
>
> On 3/26/2014 1:29 PM, Hare, Ed W1RFI wrote:
>
>> One report I received back indicated that one plasma TV was cured with
>> common-mode chokes, but two other models were not. All were Samsung
>> products.
>>
>> -----Original Message-----
>> From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of Dale J.
>> Sent: Wednesday, March 26, 2014 2:44 PM
>> To: Tom Thompson
>> Cc: rfi@contesting.com Reflector
>> Subject: Re: [RFI] ARRL to FCC...
>>
>> Tom,
>>
>> I'd love to do a lot of stuff with their tv, but it's not my house and I
>> hate to impose on them. I have to catch the neighbor outside on a weekend
>> and chat with him a little and maybe something might get going. As you can
>> see I'm a little squeamish about imposing on other people's home and
>> property. I guess I wouldn't like it much and therein lies my problem, hi.
>> But I'll work on it. Maybe by the time I finally can do some real
>> investigation the TV will die.
>>
>> Dale, k9vuj
>>
>>
>>
>> On 26, Mar 2014, at 13:18, Tom Thompson <tlthompson@qwest.net> wrote:
>>
>> Dale,
>>>
>>> I checked with Costco and they only carry LED back lit TV sets now. In
>>> thinking about it further, I don't think making a measurement on the power
>>> cord with an RF current probe would be too definitive anyway because of the
>>> RFI coming from the other sets connected on the same circuit. It would be
>>> instructive if you could conduct some tests on your neighbor's set. Would
>>> it be possible to use a battery and quiet inverter to power the set with
>>> all other wires disconnected? You might have to connect the cable to get
>>> the screen to light. If you could do that and it eliminated the RFI then
>>> the line filters Ed suggested might work for you.
>>>
>>> Just some thoughts.
>>>
>>> Tom W0IVJ
>>>
>>> On 3/26/2014 2:23 AM, Dale J. wrote:
>>>
>>>> My next door plasma is broadband hash with various bumps along the way.
>>>> I have one of those bumps especially bad at 3.857, it's 20 db over 9 and
>>>> sounds like a motor running but changing speed and sometimes stopping and
>>>> starting. The broadband hash is all over the 80 meter band and 40 too.
>>>> The upper bands are less affected. I suspect part of the noise is from a
>>>> switching power supply in the plasma tv, that might be what that motor
>>>> sounding noise is not sure though. I wish it were my TV, I could then find
>>>> out more how these things tick before permanently disabling it. Makes it
>>>> difficult on my USAF MARS net too.
>>>>
>>>> Dale, k9vuj
>>>>
>>>>
>>>>
>>>> On 25, Mar 2014, at 21:16, David Cole <dave@nk7z.net> wrote:
>>>>
>>>> Imagine thousands of little lightening bolts... Thats Plasma TV.
>>>>> --
>>>>> Thanks and 73's,
>>>>> For equipment, and software setups and reviews see:
>>>>> www.nk7z.net
>>>>> for MixW support see;
>>>>> http://groups.yahoo.com/neo/groups/mixw/info
>>>>> for Dopplergram information see:
>>>>> http://groups.yahoo.com/neo/groups/dopplergram/info
>>>>> for MM-SSTV see:
>>>>> http://groups.yahoo.com/neo/groups/MM-SSTV/info
>>>>>
>>>>>
>>>>> On Tue, 2014-03-25 at 18:28 -0600, Tom Thompson wrote:
>>>>>
>>>>>> Ed,
>>>>>>
>>>>>> I checked out a few plasma tv sets a couple of years ago with a
>>>>>> portable shortwave receiver. The RFI was coming right out of the
>>>>>> front of the set which made sense since that was where the discharge
>>>>>> was occurring.
>>>>>>
>>>>>> Tom W0IVJ
>>>>>>
>>>>>> On 3/25/2014 12:31 PM, Hare, Ed W1RFI wrote:
>>>>>>
>>>>>> Thanks, Dale.
>>>>>>>
>>>>>>> We can then see if the TV is still in production. If it is no
>>>>>>> longer manufacturered, it may be a harmful interference complaint, not a
>>>>>>> possible emissions-limit violation.
>>>>>>>
>>>>>>> The ARRL Lab would also be willing to provide a few filters to try,
>>>>>>> if your neighbor is willing to work with you. Some have speculated that
>>>>>>> the noise comes directly from the TV, and this could be true, but I
>>>>>>> still
>>>>>>> tend to think in terms of noise coming out the AC mains and possibly
>>>>>>> also
>>>>>>> being radiated by the shield of the incoming coaxial feed line.
>>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Dale J. [mailto:dj2001x@comcast.net]
>>>>>>> Sent: Tuesday, March 25, 2014 2:29 PM
>>>>>>> To: Hare, Ed W1RFI
>>>>>>> Cc: rfi@contesting.com
>>>>>>> Subject: Re: [RFI] ARRL to FCC...
>>>>>>>
>>>>>>> Ed
>>>>>>>
>>>>>>> I'll see if I can get that information from my neighbor, but it will
>>>>>>> take a while. I have to actually get in the house and look at the back
>>>>>>> of
>>>>>>> the TV and get the model number because I don't think they know for
>>>>>>> sure.
>>>>>>> As soon as I get it I'll send you a email.
>>>>>>>
>>>>>>> Tnx
>>>>>>> 73
>>>>>>> Dale, K9VUJ
>>>>>>>
>>>>>>>
>>>>>>> On 25, Mar 2014, at 13:04, "Hare, Ed W1RFI" <w1rfi@arrl.org> wrote:
>>>>>>>
>>>>>>> If the ARRL Lab can get some reports involving specific model
>>>>>>>> numbers, we can do some testing and find out where these plasma sets
>>>>>>>> stand.
>>>>>>>> I had a report in MD that involved two Samsung plasma TVs. One made
>>>>>>>> very
>>>>>>>> loud radiated noise, while the 2nd model, also a plasma TV, was quiet.
>>>>>>>>
>>>>>>>> I need reports that involve a plasma TV operating in a neighbor's
>>>>>>>> home causing harmful interference. So far, most of the reports have
>>>>>>>> been
>>>>>>>> about the QRZ.com and RFI list discussions, not a specific report.
>>>>>>>>
>>>>>>>> The ARRL Lab can measure conducted noise and radiated noise from
>>>>>>>> devices, but we really need to start with actual, non-general reports.
>>>>>>>>
>>>>>>>> Ed Hare, W1RFI
>>>>>>>> ARRL Lab
>>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of KD7JYK
>>>>>>>> DM09
>>>>>>>> Sent: Friday, March 21, 2014 12:23 AM
>>>>>>>> To: rfi@contesting.com
>>>>>>>> Subject: Re: [RFI] ARRL to FCC...
>>>>>>>>
>>>>>>>> : Now if they would recall all the damn plasma TV's out there
>>>>>>>> doing the same
>>>>>>>> : thing it would really tickle my butt cheeks...but, any such
>>>>>>>> action is
>>>>>>>> : goodness!
>>>>>>>>
>>>>>>>> How mant times have you contacted the FCC regarding the
>>>>>>>> interference to your licensed service?
>>>>>>>>
>>>>>>>> Kurt
>>>>>>>>
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