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Author Topic: Plasma RFI  (Read 15279 times)

Posts: 901

« Reply #15 on: January 16, 2013, 03:54:09 AM »

Mine is definitely 60 cycle in nature. Logged S9+10db noise through 30m band almost exactly 60hz apart. Just to be sure I am going to switch all the power off in the house except for the radio to make sure there isn't something new in the house causing the noise. The NB on the 940 still does a good job knocking it down, but I really want to find the source. It appears to be on 24/7.

Posts: 12628

« Reply #16 on: January 16, 2013, 01:31:14 PM »

This is a rare exception and not the rule for Plasma TV's which by their very design are RFI noisy.

Perhaps not necessarily so rare. We had a 63" Samsung plasma set that made a horrendous racket on many of the HF bands. Could not go on 160, 80, or 40 meters when it was turned on. That TV was moved to another room where it is seldom used. In it's same physical place we put a 65" Panasonic SmartViera plasma set. Almost RFI-free. I can hardly tell when someone has turned on that TV when I'm on the radio. I'm happy that this set is not a problem-causer, because before we bought it we tried a 65" Sharp Aquos LED. No RFI, but the picture totally sucked. Sad but true - a $2,600 TV with sports movement artifacts and a teensy viewing angle.

I feel for those folks plagued by plasma RFI, but if you are shopping for a quality picture, don't completely rule out plasma. Make sure whoever you buy it from gives you a written statement that if it screws up your radio - it goes back - no charge to your pocketbook. We did that with Best Buy and the Sharp TV. Although it didn't cause RFI, it wasn't a keeper - they came and hauled it away when they delivered the Panasonic. Didn't cost us a penny extra.

Early large screen LED TV's were not on cutting edge and plasma was cheaper to build but use 6 to 8x more power than a modern LED back lit LCD TV.

Ham since 1969....  Old School 20wpm REAL Extra Class..

Posts: 19

« Reply #17 on: January 18, 2013, 05:08:19 PM »

I was facing similar RFI problem at my home.  The interference was from 1000KHz to more than 23.5 MHz frequency range.
First I thought it was from my neighbors.  To confirm it I took a portable Shortwave radio and started to walk away from my house.  RFI was getting reduced.  I realized that the RFI was coming from my house.   I started switch off electrical /electronic equipments  one by one.   Finally when I pull a wall wart (SMPS from Sabrent) for my new external hard drive enclosure RFI stopped immediately.  I got amused and broke open the wall wart and found that the design of it did not have any filters in the front to suppress the RFI. Cheap design to save production cost .(made in China).  I stopped using that device and later trashed it. 

Most of the cheap holiday sale electronics are not designed with RFI filters.  Also I found many electronic dimmers and fan speed controllers are creating RFI.

Posts: 6252

« Reply #18 on: January 19, 2013, 07:34:52 AM »

Plasma TVs get the blame because when they were first introduced, the lower priced ones DID cause massive RFI.  Lately, those issues have gone away since the manufacturers are now aware of them.

Hey, I just got a Panasonic 51 inch SmartViera myself, and it's also nearly RFI free when on.  When off, no RFI at all.

Posts: 1513

« Reply #19 on: January 28, 2013, 11:47:14 PM »

The problem is that the major name brand products fix their design issues .The failed designs end up in a Chinese copy factory and they are churned out by the millions under various brand names.

It does not help that the EMC laws are not enforced at the borders, they just accept the fraudulent EMC markings from the Chinese factories. Whats worst is that they  allow EMC labs in China to do the certification
and they will say anything  for money. The EMC certification process in China is corrupt and non existent in other countries.

The real problems for hams in Western  democratic countries is that the authorities wont do anything  about prosecuting companies who import products that dont meet EMC standards.
The Chinese and most importers know this and thats why they  just keeps on importing the junk.

Plasma TVs get the blame because when they were first introduced, the lower priced ones DID cause massive RFI.  Lately, those issues have gone away since the manufacturers are now aware of them.

Hey, I just got a Panasonic 51 inch SmartViera myself, and it's also nearly RFI free when on.  When off, no RFI at all.

Posts: 901

« Reply #20 on: February 04, 2013, 03:47:11 PM »

I've posted a new video of the interference. The interference is all the same noise just depends which antenna I am hearing it on. The noise blanker does a good job of knocking it down but still puzzled by it's source.

Here's the link for the video:


Posts: 5

« Reply #21 on: February 14, 2013, 06:47:07 AM »

My Panasonic 50" is  4 yrs old and sits two feet from my shack desk, on the other side of the wall. 

No  obvious problems here, even when I switch it on and off.

I do get some misc. spurs from the CATV which runs from under my desk over to the TV., to my comuter and  phone system but not a big deal.

My problem has been power line noise at 59+20.  Found the direction with my vhf yagi ( 6m)  and used Googe maps to  drive a couple of nearby streets.  Found  two very noisy power poles on the car's AM radio ( using 1700 khz)  Called the utility. Two linemen came over and I took them to the poles.  First pole they climbed, insepcted and tightened ALL the hardware.  No effect.  I took them to the next pole, and as soon as they got out of their truck, said: "This is it! I can hear arcing from atop the pole."  Sure enough, the lightning arrestor was continuously arcing.  He pryed the  arrestor spark gap  wider apart and all noise stopped.  The arc gap had never cleared following a strike.  Also, the rubber boot encasing the contacts had been blown apart...ripped apart all the way around its circumference.  They changed it out and no more problems.

Well, the S9+20 nmoise was gone, but now I hear intermittent S9 noise from two other directions plus a steady stream of 1 second interval popping noises.  More  work to do!  But I can operate 160-80-60-40 meters most of the time and really hear the DX again.

Huge progress but more needed.
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