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Author Topic: Plasma RFI  (Read 7507 times)
VE3TMT
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Posts: 419




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« on: January 11, 2013, 09:17:43 AM »

I am assuming one of my neighbors has purchased a plasma TV over the holidays as I am now getting 20 over S9 noise across the entire 160m and 80m bands. The NB on my 940 drops it down quite a bit, but still there. It is readable up through 20m but not as bad.

Is VHF or UHF equipment subject to the same type of interference or are these frequency ranges too high to be affected?

If I can't resolve it, it may be the final decision maker to swap out my HF station and go V/UHF .
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WB4SPT
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Posts: 150




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« Reply #1 on: January 11, 2013, 10:11:09 AM »

THat really bites.  In your case, the culprit appears to start a a fairly low frequency and generally go down in amplitude as the frequency increases.  There are some notable culprits that start being "bad" in the VHF band and go up from there.  Desktop modems, and even cable TV are notable examples.  I hear an awful lot about Samsung and their plasma widescreens.  Would like to see a radiated plot from those someday. Are we sure they pass Part 15 Class B???

One more comment;  It could be that these TV's have a sensitivity to some energy in the Ham band.  I'm not saying to intentionally cause an issue, but there might be some legal mode, frequency, time of day that might compel the owner to turn in the "defective" TV and shop for a "good" TV.
« Last Edit: January 11, 2013, 10:14:16 AM by WB4SPT » Logged
VE3TMT
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Posts: 419




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« Reply #2 on: January 11, 2013, 10:19:23 AM »

Yeah I was thinking of borrowing a buddies Titan amp and smoke them out, literally.
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VE3TMT
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« Reply #3 on: January 11, 2013, 01:59:00 PM »

I uploaded a video to YouTube, may or may not be plasma interference.

http://youtu.be/p9MKvsKeK7o


Max
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WB4SPT
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« Reply #4 on: January 11, 2013, 02:03:57 PM »

saw ur vid.  hard to say.  if the noise goes away at nite just before the house lights extinguish, then that's a pretty good giveaway on it being a TV.
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WB4BYQ
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« Reply #5 on: January 12, 2013, 07:40:16 AM »

i have seen rfi from plasma tv.  had neighbor 25 feet from house with one.  the dsp or nb will not clear up the rfi as you have.  this in not plasma.  this is some type of arching. 

richard
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VE3TMT
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« Reply #6 on: January 12, 2013, 08:18:36 AM »

i have seen rfi from plasma tv.  had neighbor 25 feet from house with one.  the dsp or nb will not clear up the rfi as you have.  this in not plasma.  this is some type of arching. 

richard

I am beginning to think that more and more Richard. No RFI on the radio this morning. I would think Saturday morning there would be noise which makes me think more and more it is something in the neighborhood arcing. I will take the dog out for a walk tonight if the noise is back armed with my G8 and see if I can pinpoint the source. At least if you have a dog with you, people don't look at you strange when they see you walking through the neighborhood holding a portable radio.
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N4NYY
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« Reply #7 on: January 12, 2013, 12:22:50 PM »

You have any of those funky gas street lamps going bad? Can you get someone in a mobile to drive around with you?
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VE3YF
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« Reply #8 on: January 13, 2013, 10:00:37 AM »

Max:
Do you have overhead hydro in your area. If so, Could be bad insulators. With all the damp weather recently that could be your issue. I dont know what the range of the of a Plasma RFI would be, but I thought Plasma on effected 80m. If not hydro issue, with all the poor quality electronics on the market it could be anything. Stay up late during the weekeday or even get up at 0200 and see if the noise is still there. That might help narrow it down....

73 De Mike
VE3YF
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VE3TMT
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« Reply #9 on: January 13, 2013, 10:24:53 AM »

Hi Mike,

I walked the neighborhood the other day with my portable receiver and could detect any jump in the signal strength. I have a feeling it is coming from a neon sign over in a strip mall not far from the house. Will have to take a drive through the neighborhood and expand my area.

73,
Max
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K2OWK
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« Reply #10 on: January 13, 2013, 02:29:06 PM »

I do not understand why a Plasma TV is immediately blamed for RFI on a ham station. My Panasonic Plasma TV from 2009 has been located about 15 feet from my station and I have never had any RFI from it. With the TV on or off my noise level is always the same, unless there is a change in atmospherics. It amazes me how a plasma TV is the first blame for any ham radio station RFI.

73s

JK2OWK
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WB4BYQ
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« Reply #11 on: January 14, 2013, 06:13:48 AM »

All the plasma tv's that i have seen, including panasonic, samsung, etc here in the usa
make lots of rfi.  just tune your radio and see.

richard
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W8JX
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« Reply #12 on: January 14, 2013, 09:15:31 AM »

I do not understand why a Plasma TV is immediately blamed for RFI on a ham station. My Panasonic Plasma TV from 2009 has been located about 15 feet from my station and I have never had any RFI from it. With the TV on or off my noise level is always the same, unless there is a change in atmospherics. It amazes me how a plasma TV is the first blame for any ham radio station RFI.

73s

JK2OWK

This is a rare exception and not the rule for Plasma TV's which by their very design are RFI noisy.
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All posted wireless using Win 8.1 RT, a Android tablet using 4G/LTE/WiFi or Sprint Note 3.
W6JHB
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« Reply #13 on: January 15, 2013, 05:32:27 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.
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Jim / W6JHB
Retired in Folsom, CA - and loving it!!!
VA2FSQ
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Posts: 511




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« Reply #14 on: January 15, 2013, 06:26:57 PM »

I'd love to only have a plasma in my neighbourhood !!
My neighbour has high intensity lighting that he insists on running during the day and called the cops on me when I asked him to turn them off during the day.They generate 40db of noise from 7MHz to 18MHz.
Not a problem anymore....
I bought a DX Engineering NCC-1 antenna phaser and an active noise antenna.  Here is a link to my web site showing a video of noise over WWV without the phaser and when it is switched in...speaks for itself.

http://va2fsq.com/wp-content/uploads/2013-Jan-15-20-43-43.avi

It's best to right click on the link and save it locally.  3.5 MB in size.
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VA2FSQ
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