Dale and Don,
Sadly, there are no radiated emission controls in the HF range. The existing
ones are all for 30 MHz and above.
Plasma emissions from the TV sets is a lot worse than from the plasma inside a
fluorescent tube lamp. Some work done years ago by a colleague in finding ways
to control radiated emissions from fluorescent lamps (these were the 4 foot
long tubes, BNOT the current CFLs) showed that the radiated emissions from such
lamps are from a rather high impedance source. Thus, the emissions were rather
easily controlled with a metal mesh screen placed over the lamps and grounded
to the fixture.
I have no idea as to whether such screening placed over the face of a plasma TV
would have significant emissions reduction, but it sure is likely to mess up
viewing of the screen display. That probably would not make good points with
the neighbors.
Retrofitting of a plasma TV for RFI reduction is certainly doable. All you
need to do is:
1. Encase the set in a metal cabinet with no untreated apertures. The display
face would have to be fitted with a conductive screen. A simple coating would
not be effective at HF.
2. All I/O connections would have to be fitted with common mode filters.
3. Figure out which will be worse: arranging the financing for such a set
(likely about the cost of a small car) or trying to view football thru the mesh
screen over the face.
73, Dale
WA9ENA
-----Original Message-----
>From: dalej <dj2001x@comcast.net>
>Sent: Nov 14, 2013 1:55 PM
>To: Donald Chester <k4kyv@hotmail.com>
>Cc: "rfi@contesting.com" <rfi@contesting.com>
>Subject: Re: [RFI] Good news: Panasonic stops making plasma TVs
>
>Don, they should force mfg to recall all plasma TV's. I have one next door,
>it's a little more than 150 feet from my shack, the noise from it is S-9 on 75
>meters. DXing is good on 75 and 40 till about 6:30 AM when the TV comes on,
>it's a kitchen TV. It's on all weekend long, I get relief during the week for
>a few hrs after about 8 AM, otherwise I am on the upper bands where the
>interference is not as bad. IT IS a bummer to say the least. I refuse to be
>the bad guy and make enemies of my next door neighbor, I feel it is NOT my
>responsibility to quiet these ill-made plasma TV's. THAT is what we pay
>government agencies for otherwise why keep funding them at all.
>
>73 and thanks for the attention
>
>Dale, k9vuj
>
>
>On 14, Nov 2013, at 12:07, Donald Chester <k4kyv@hotmail.com> wrote:
>
>> The bad news is that Panasonic is just one manufacturer, and there are
>> already millions of plasma TVs in service that are likely to continue
>> spewing out their garbage for years to come.
>>
>> Those things are everywhere! Fortunately for me, I live out in the country
>> and don't have this problem, and a plasma TV will never enter these
>> premises, but many if not most hams I talk to, who live in a densely
>> populated urban area, tell me that plasma TV interference has made the lower
>> HF bands difficult or downright unusable. I wonder if this problem might not
>> be far more widespread than most people
>> think, and a major reason that activity on 160m and 75m has clearly dwindled
>> in recent years.
>>
>> This shouldn't even be an issue. This kind of interference is clearly a
>> violation of FCC rules and never should have been allowed to get out of
>> hand to the extent that it has. RFI hash trashing up the bands could end up
>> being as much a threat to amateur radio as TVI was back in the 50s.
>>
>> I don't understand why ARRL and the AM broadcast industry, along with other
>> HF users such as aviation and the military, haven't joined together to
>> sponsor an urgent research project to retrofit plasma TVs to eliminate the
>> RFI, and then once demonstrated that this would be feasible, exert pressure
>> on congress and the FCC to follow the law that already exists on the books,
>> and force manufacturers and existing users to clean those things up, just as
>> the FCC did with the guy who had the defective well pump motor. Amateur
>> radio probably couldn't accomplish this alone, but a combined effort with
>> other interests probably could pull it off. Remember, NTIA nixed a real 60m
>> amateur band because the government insisted that those HF channels were
>> strategically indispensable for national security. As with paranoia over the
>> health effects of rf, "national security" is another hot-button issue that
>> would likely resonate with politicians and the public.
>>
>> Don k4kyv
>> _______________________________________________
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>> RFI@contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
>
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