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Author Topic: NEW TV WITH LITTLE TO NO RFI TO HF RIG  (Read 11945 times)
KT6DX
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Posts: 4




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« on: November 24, 2010, 10:04:53 AM »

I am in the market for a new 50" or bigger TV that will not cause interference to my home HF rig. I have picked up some pointers from the RFI forum and I will not be buying a plasma TV. My old TV (1998 Mitsubishi 60" projection TV) was terrible When the TV was on it interfered across the bands. When it was turned off but plugged in it would have a lesser(but still irritable) interference that was only about a 3 kc's wide but was found about every  60 kc's and would slowly travel ( maybe it was the quick start circuit).The installation of proper chokes and filters helped just a little in both cases.
        In any case, if you have a newer LCD or LED big screen that does not cause any interference when turned on and when turned off but plugged in, please let me know the make and model. It wouldn't hurt if you can let me know the distance your TV is away from your rig and antenna system.
                               Your answer is greatly appreciated
                                         Thanks-Paul
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W3LK
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« Reply #1 on: November 24, 2010, 12:51:07 PM »

My 40" Samsung LN40C530 neither generates RFI on any frequency nor is it affected by 1kw on HF or 100w on VHF/UHF. It may be an invalid assumption on my part but the other Samsungs probably behave the same way.

73,

Lon - W3LK
Naugatuck, Connecticut
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
K8AC
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Posts: 1896




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« Reply #2 on: November 24, 2010, 01:51:48 PM »

46" LCD Sony Bravia here (2 years old) - no idea what the model number is.  Nothing heard from the TV on any HF band and it's been immune to my 1,500W output on 160 through 10 (and 200W on 6M).  Antennas are 50 to 100 feet away from the TV. 
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KH6AQ
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Posts: 7767




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« Reply #3 on: November 25, 2010, 07:37:12 AM »

If no one gives you a recommendation for a new 50" TV you might do your own testing. A small AM radio held a couple of feet from the operating televisons at a store might steer you away from a noisy one. Walmart has all their televisions set up and operating on the same video source.

According to the posts on eham the LCD televisions are the quietest. You might check out an LCD/LED TV. These use LEDs rather than flourescent lamps for illuminating the screen and might be RF quieter as well as consuming less power. I recently purchased a 32" LCD/LED Vizio brand and there is no addiational noise on the bands with it ON. It consumes only 34 watts. We chose this TV because the image was superior to the Sony 32" LCD (that cost $40 less).

Looking at walmart.com there are several televisions of 50" or larger with most being the LCD type priced around the $1000. They stock a 55" Vizio LCD/LED (the only >47" LCD/LED TV on their website ) and the price of that is  $1688. They stock a Vizio 47" LCD/LED for $998.

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W2MV
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Posts: 244




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« Reply #4 on: December 02, 2010, 08:34:54 AM »

Good info to know these days will the multitude of offending devices around. One comment though, the "AM radio" test might not be all that useful. What really matters is if the RFI will be picked up by your normal ham antenna. I've done the SW/AM radio test near appliances with positive results, only to discover that I did not notice anything in my ham receiver. Still can't hurt, though.
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KH6AQ
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« Reply #5 on: December 02, 2010, 09:15:31 AM »

The AM radio test is a relative test. One tests all the TV's in the store and then avoid purchasing one that stands out as noisier than the rest. Otherwise purchase what you like, take it home and see if it's an RFI generator. If it is return it to the store and buy another. Rinse and repeat.
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KT6DX
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« Reply #6 on: December 02, 2010, 11:47:02 AM »

At this point I would like to thank all of you for your input. Since Im not in a big hurry ( Old TV is a RFI pain but still works) I would like to get more feedback on Make and Models that do not cause the 2 types of interference described in my original post.The bigger sample the better.
                                   Thanks again and 73,
                                                                   PAUL
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W2MV
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« Reply #7 on: December 06, 2010, 06:21:14 AM »

I think what would be helpful is to compile a S***TLIST of makes and/or models to avoid, i.e., those which are known RFI generators.
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KG4YMC
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Posts: 298




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« Reply #8 on: December 15, 2010, 08:07:50 PM »

Just curious, would the " refresh rate" have any effect, also noise wise, would the 1080pi  be better quality as far as the noise level?Kg4ymc   oh, as far as the L.C. D. models go ?  terry 
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AA4HA
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« Reply #9 on: December 16, 2010, 07:17:00 AM »

I think that it is an impossible task to keep track of what consumer electronic goods emit less EMI/RFI. Even the FCC has thrown its hands up in the air and now grants very broad approvals for product certification. For any list of compiled results you would need a standardized set of laboratory grade tests, otherwise it is all subjective to the listeners. Even minor, "in model" design changes during a product life cycle will cause changes in the levels of interference that "we" are interested in. Manufacturers could give a care less on signal levels below the thresholds /or/ frequencies of interest by the certifying body (CE, FCC, whatnot).

Now if everything was built to TEMPEST standards <sigh>, I can only dream...   http://en.wikipedia.org/wiki/TEMPEST

If you had to make a few general statements they could be;

1. Stay away from a plasma screen. It is almost a 100% guarantee that it will be a noise generator.

2. LED illuminated LCD screens will be quieter than fluorescent illuminated screens.

3. How any set is installed will make a big difference in the RFI levels. Keep cords as short as possible with good, well shielded cables.

4. Grounding is your friend. Do not rely just on the ground pin.

5. An external RFI line filter will always reduce the amount of conducted emissions from any device.

6. Do not count on the same manufacturer being consistent in minimizing EMI/RFI. Sometimes the most subtle of changes in a design can result in a noisy model.

7.  Plastic cases have absolutely no use as an EMI/RFI shield, that little oscillator on a logic board can be heard a half a block away.

8. Every amateur radio operator should own large numbers of clamp on ferrite filters.

Tisha Hayes
AA4HA
« Last Edit: December 16, 2010, 08:32:32 AM by Tisha Hayes » Logged

Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
KT6DX
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« Reply #10 on: February 15, 2011, 11:28:39 AM »

ALRIGHT! The verdict is finally in.
I ended up buying a Samsung 55" LCD HDTV model #LN55C630   It has a beautiful HDTV picture.
Oddly enough the only problem I encountered was not with the TV but with the new HDTV cable box from Comcast that was required for HDTV viewing.
       When I first hooked everything up I was picking up some strong interference on 40m,80m and 160m even with TV off. I started to unplug devices and once I unplugged the power to the HDTV cable box the interference went away.
         I put two ferrite toroid chokes (FT240-43) that i had on hand on each end of the HDTV cable box 12v power supply cord. One at the connection to the box and one at the connection to the wall outlet. I put about 10 turns around each toroid  choke.  BINGO!  problem solved.
      I want again to thank you all for your input. Hopefully this thread will help others
                                           Paul-KT6DX
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SIGINT11
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« Reply #11 on: June 21, 2011, 02:32:09 PM »

My kids purchased me a small Samsung series 5000/5010  un22d5000nf  led flat screen at best buys for fathers day and I have it 3 feet from my radios and I have not noticed any interference on any bands yet.   
  for anyone interested.
     Thanks
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W1AEX
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Posts: 84


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« Reply #12 on: June 24, 2011, 08:04:11 PM »

Thanks for reporting the results of your HDTV purchase Paul, and also the solution for the Comcast STB noisemaker. I have a 3 year old Samsung LCD HDTV that is absolutely silent across the HF bands. It sits only 6 inches from my pair of 3-500's and doesn't flinch at all when I'm running 1500 watts out from 160 - 10 meters.

It's my hope that Plasma televisions will go away in the near future. I cringe every time I see a promotional offering by the local auto dealers where they give away "free" plasma televisions to the first 5 buyers on a given weekend. I'd hate to see any of those nasty "free" plasmas landing in my neighborhood...

73,

Rob W1AEX
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W7VO
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« Reply #13 on: July 27, 2011, 05:12:09 PM »

I had big problems with my Samsung 55 inch C-7000 series LED TV getting RFI into the underbezel touch sensors and causing it to switch inputs when I was on 40M with a KW. The technician from the repair shop disconnected the touch panel controls and all was good after that. Have to use the remote now, but we always did anyway.....

Here is the thread: http://www.eham.net/ehamforum/smf/index.php/topic,70297.0.html

73;

Mike, W7VO
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KT6DX
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« Reply #14 on: August 23, 2011, 12:52:58 PM »

Its nice to see the continued comments.
To Mike (W7VO) Thanks for the info. As its turns out one day I was asked to get on 75 phone ( which I hardly ever do) and my Samsung 55" turned on by itself. Well I have not been on 75 meter since so I probably wont pursue fix yet , but thanks for pointing me in the right direction. Sounds like it t could be the touch sensor.

Now that I'm here I will mention another situation that needed to be rectified.  I have a small TV in my bedroom and had to get a small Digital Adapter from Comcast in order to receive more digital channels. Turns out this little adapter was also generating interference to my HF Rig. After experimenting with the  placement of a FT240-43 choke , I was able to eliminate the interference by placing the choke (10 turns) on the coax going into the"" input" on the adapter.
                                           73,
                                                Paul - KT6DX
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