Hi Don,
Thanks for the information. Those common mode chokes certainly are
effective. Your experience would suggest that it is not just radiation
emitting from the front of the screen that causes the RFI. Since common
mode choking is a function of both the source and the load impedance, it
would be interesting to isolate the TV from the house wiring completely
by running the TV on a battery/inverter in order to completely isolate
it electrically from the house wiring.
Your average tracking time of 10 minutes illustrates that with a little
practice finding the RFI source is the lesser problem. Fixing it is
another matter. Your youtube video certainly shows this.
Good documentation!
73, Tom W0IVJ
On 3/26/2014 6:00 PM, Don Kirk wrote:
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
<mailto: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
<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 <mailto: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
<mailto: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
<mailto: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 <http://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
<mailto:dj2001x@comcast.net>]
Sent: Tuesday, March 25, 2014 2:29 PM
To: Hare, Ed W1RFI
Cc: rfi@contesting.com
<mailto: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
<mailto: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
<mailto:rfi-bounces@contesting.com>]
On Behalf Of KD7JYK
DM09
Sent: Friday, March 21, 2014 12:23 AM
To: rfi@contesting.com
<mailto: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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