[RFI] New HDTV Purchase - What to Avoid?

[Dave Cole]

Thankfully, the "Lightening in a box" TVs are no longer made...

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 12/8/20 2:55 PM, Rob Atkinson wrote:
> I second the advice on taking a portable sw receiver to the store.
> Around 7 years ago I took my Grundig Yachtboy receiver with me to a
> Best Buy.  I didn't plan on making a purchase.  I wanted to try to ID
> the source of RFI at home.  I suspected the problem was a plasma TV
> next door but since I didn't know what one sounded like on 75 and 160
> m. I figured I could hear one at the TV display in the store and find
> out.
> 
> I extended the telescoping antenna, put the receiver on AM on some
> frequency in the 160 m. ham band and began to walk around.   Much to
> my surprise, most of the equipment powered on for display was
> extremely quiet, at least on medium wave and 75 meters.  In fact, the
> overhead fluorescent lamps generated most of the noise.   That changed
> as I approached the TV area.  From about 60 feet away I heard the same
> thing I had been hearing at home which became the unmistakable
> signature AM sound of plasma TV RFI.  Once in the TV department the
> plasmas really blasted, mostly from the screens where tiny gas tubes
> with electrodes in them continually fired.  Some sets showed in-house
> slide shows of fixed images.  These didn't make as much noise.  The
> sets when dark between images generated much less noise.  But live
> action, such as a football game whereby pixels were constantly firing
> by the thousands generated the mother of all RFI.   Back then, sports
> enthusiasts were nuts for plasmas because they lacked ghosting and had
> zero latency.  I peered behind one through the air vents and saw that
> the entire backside was nothing but heat sinks and electrolytic caps.
> What a nightmare.   The other sets were LCD as I recall and they were
> okay.   I hope TV technology has improved and ATSC 3.0 marks the end
> of plasma TVs.
> 
> I don't know if used plasma TVs are still sold or not but yikes, don't
> ever buy one or live next to one.
> 
> 73
> 
> Rob
> K5UJ
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