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post #1 of 44 Old 01-21-2014, 07:09 PM - Thread Starter
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Hey Everyone

 

New here, but not new to forums.  I've got a question for you that I'm hoping some of you experts can hop in on because I'm out of ideas.  First of all, here's the details on my setup

 

Antenna - RCA ANT751

Mounting Location - Garage Rafters

Aimed at about 122-123 degrees

Downlead to a 4-way amplified splitter

 

Here is my TVfool info:

 

 

Now here's my issue.  I currently have 2 tvs hooked up in the house, an LG from '06-'07 upstairs and a brand new Vizio in the basement.  The Vizio gets perfect reception on all of my stations that I'm picking up but for some reason my LG is getting pixelation only on channel 11-1 (Kare).  The pixelation really only happens at the very when one commercial transitions into another, commercial into show, or show into commercial.  

 

Now, what I've done for troubleshooting.  I've completely replaced the coax cable with RG6 from the amplified distributor to the TV.  My signal strength isn't showing any issues on that specific station.  I brought in a smaller TV that I could easily move around (el cheapo something small) and plugged that into the coax that the LG is usually hooked up to and I didn't see any pixelation for the duration of watching it.

 

Now, here's the conclusion I've come to...but I don't have any background on any of this stuff.  I'm guessing this issue is stemming from the LG TV, maybe a bad tuner?  If it were something related to the signal, then it should be affecting the downstairs Vizio too, right?  What do you guys think?  It's driving me crazy!

 

Thank you in advance for the advice!

 

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post #2 of 44 Old 01-21-2014, 08:19 PM - Thread Starter
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A little more research done and I've found two other possibilities:

- Overamplified

- VHF Interference

 

I'm questioning the overamplified portion because if the upstairs LG is being overamplified, then wouldn't the Vizio downstairs?  I'll check that theory by unplugging the amplifier and tuning into channel 11...after watching some Netflix with the gf.  She's getting annoyed by my obsession over this :)

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post #3 of 44 Old 01-22-2014, 12:14 AM
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The older the TV, the higher the likelihood that it has an inferior tuner that will produce pixelation at times where newer TVs, with later generation tuners, will handle the signal just fine. Your research has already led you to what I would've suggested, namely that you should see what happens if you replace the amplified splitter with a non-amplified one. If that doesn't work, you could look into the VHF interference (primarily from FM stations) possibility by adding an inexpensive FM trap to your setup.
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post #4 of 44 Old 01-22-2014, 12:40 AM
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Quote:
Originally Posted by agus0103 View Post

The older the TV, the higher the likelihood that it has an inferior tuner that will produce pixelation at times where newer TVs, with later generation tuners, will handle the signal just fine. Your research has already led you to what I would've suggested, namely that you should see what happens if you replace the amplified splitter with a non-amplified one. If that doesn't work, you could look into the VHF interference (primarily from FM stations) possibility by adding an inexpensive FM trap to your setup.

I'm not sure that newer generation tuners actually do a better job with VHF. It really hasn't been addressed here, so I'm not sure. I entered digital with a fifth generation tuner that most felt was far superior to earlier ones for being able to deal with multipath. Has any progress been made in dealing with electrical interference? It's certainly a problem with VHF. It's also a problem with UHF, at least here. Here, FM stations are not to blame.
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post #5 of 44 Old 01-22-2014, 05:43 AM
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The pixelation really only happens at the very when one commercial transitions into another, commercial into show, or show into commercial.

Hard to believe that it's an interference or even a reception issue if that's the only time the symptom occurs.

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I'll check that theory by unplugging the amplifier and tuning into channel 11

If you simply unplug the power cord, you're turn the amp into an attenuator. Bypass the amp completely to test.
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post #6 of 44 Old 01-22-2014, 06:57 AM - Thread Starter
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I'm skeptical with the non-amplified splitter since when I initially set all of this up it went Antenna->2 way splitter (one straight to LG another to 3 way non-amplified splitter which went to Vizio) and the signal wasn't strong enough for the Vizio.

 

Last night, I stayed up and putzed around with trying to find interference.  I unplugged all electronics that are around the TV and it seemed to help a little, but it's still doing it.  I'm going to use the AM radio trick this evening when I get home from work, but in the mean time are there any main culprits I should be looking for?  I keep seeing FM interference, does that mean simply having a radio with an FM antenna close by can cause interference?

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post #7 of 44 Old 01-22-2014, 08:02 AM
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Quote:
Originally Posted by WRX1986 View Post
 

I'm skeptical with the non-amplified splitter since when I initially set all of this up it went Antenna->2 way splitter (one straight to LG another to 3 way non-amplified splitter which went to Vizio) and the signal wasn't strong enough for the Vizio.

 

Last night, I stayed up and putzed around with trying to find interference.  I unplugged all electronics that are around the TV and it seemed to help a little, but it's still doing it.  I'm going to use the AM radio trick this evening when I get home from work, but in the mean time are there any main culprits I should be looking for?  I keep seeing FM interference, does that mean simply having a radio with an FM antenna close by can cause interference?


When you had the signal split two ways and one leg going to your LG how did that work for the LG? If it still had issues then a 4 way would only be worse, oh and doing it the way that you did(split 2 ways then  3 ways) would actually give you a lower signal to your Vizio than just a 4 way splitter, more signal would have went to the LG but less to the Vizio.

I believe the FM interference talked about isn't from a FM radio but rather a FM transmitter or strong FM stations that might be close by.

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post #8 of 44 Old 01-22-2014, 09:04 AM - Thread Starter
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Originally Posted by jjeff View Post
 


When you had the signal split two ways and one leg going to your LG how did that work for the LG? If it still had issues then a 4 way would only be worse, oh and doing it the way that you did(split 2 ways then  3 ways) would actually give you a lower signal to your Vizio than just a 4 way splitter, more signal would have went to the LG but less to the Vizio.

I believe the FM interference talked about isn't from a FM radio but rather a FM transmitter or strong FM stations that might be close by.

 

Hey jjeff, thanks for the help. 

 

Here's a more detailed version of my evolution of this project.

- At the very beginning, I had the downlead from the antenna split in 2...one going straight to the LG and the other going to a 3 way non-amplified spliter which lead to the Vizio.  The LG was doing the pixelation on ch.11 while the Vizio just wasn't getting great reception on many stations.  It was the same type of distortion as the Vizio though.

- Next step, I added the 4-way amplified splitter and the Vizio got better...perfect actually.  LG still has pixelation.

- Latest step, replaced all coax from the 4-way amplified split heading to the LG in hopes of fixing pixelation...no luck.

 

I think my next step is going to be adding an FM trap to the downlead of the antenna.  It's a cheap enough part to toss on for an experiment.  It looks like I have a decent amount of radio towers in my area and one that is in "Shoreview" which is where the majority of the TV broadcasts are coming from.

 

Is anyone with more knowledge able to detect an issue with the below radio tower chart and my TVfool pull I posted in the first post?

 

Thanks everyone!

 

Info   Call Sign  Frequency   Dist./Signal   City  School  Format
 [BC] [Info]  KBEM   88.5 FM   15.2 mi. Signal Strength 3   Minneapolis, MN  Minneapolis Public Schools  Jazz 
 [BC] [Info]  KCMP   89.3 FM   36.5 mi. Signal Strength 3   Northfield, MN     Public Radio 
 [BC] [Info]  KPCS   89.7 FM   28.1 mi. Signal Strength 2   Princeton, MN     Religious 
  [Info]  KMOJ   89.9 FM   12.2 mi. Signal Strength 3   Minneapolis, MN     Urban Contemporary 
 [BC] [Info]  KFAI   90.3 FM   14.4 mi. Signal Strength 2   Minneapolis, MN     Variety 
 [BC] [Info]  KNOW   91.1 FM   14.0 mi. Signal Strength 5   Minneapolis-Saint Paul, MN     Public Radio 
 [BC] [Info]  K221ES (KFXN)  (CP) Help   92.1 FM   15.6 mi. Signal Strength 2   Albertville, MN     Sports 
 [BC] [Info]  KQRS   92.5 FM   14.7 mi. Signal Strength 5   Golden Valley, MN     Classic Rock 
 [BC] [Info]  W225AP (KFXN)  (CP) Help   92.9 FM   14.4 mi. Signal Strength 2   Saint Paul, MN     Sports 
  [Info]  W227BF (KFXN  93.3 FM   14.4 mi. Signal Strength 2   Shoreview, MN     Asian 
 [BC] [Info]  KXXR   93.7 FM   14.7 mi. Signal Strength 5   Minneapolis, MN     Rock 
 [BC] [Info]  KSTP   94.5 FM   14.0 mi. Signal Strength 5   Saint Paul, MN     Hot AC 
 [BC] [Info]  KNOF   95.3 FM   14.4 mi. Signal Strength 3   Saint Paul, MN     Religious 
  [Info]  WLKX   95.9 FM   17.3 mi. Signal Strength 2   Forest Lake, MN     Regional Mexican 
 [BC] [Info]  KTWN   96.3 FM   10.1 mi. Signal Strength 4   Edina, MN     Hot AC 
 [BC] [Info]  KTCZ   97.1 FM   14.7 mi. Signal Strength 5   Minneapolis, MN     Adult Album Alternative 
 [BC] [Info]  K249ED (KFXN  97.7 FM   3.6 mi. Signal Strength 4   Albertville, MN     Sports 
 [BC] [Info]  WWJO   98.1 FM   54.4 mi. Signal Strength 2   Saint Cloud, MN     Country 
 [BC] [Info]  KTIS   98.5 FM   14.7 mi. Signal Strength 5   Minneapolis, MN  Northwestern College  Christian Contemporary 
 [BC] [Info]  KSJN   99.5 FM   14.7 mi. Signal Strength 5   Minneapolis, MN     Classical 
 [BC] [Info]  K260BA (KFXN  99.9 FM   12.5 mi. Signal Strength 2   Coon Rapids, MN     Sports 
 [BC] [Info]  KFXN   100.3 FM   14.7 mi. Signal Strength 5   Minneapolis, MN     Sports 
 [BC] [Info]  W264BR (KUOM  100.7 FM   15.2 mi. Signal Strength 1   Falcon Heights, MN  University of Minnesota  College 
 [BC] [Info]  KDWB   101.3 FM   14.7 mi. Signal Strength 5   Richfield, MN     Top-40 
 [BC] [Info]  WHMH   101.7 FM   47.6 mi. Signal Strength 2   Sauk Rapids, MN     Rock 
 [BC] [Info]  KEEY   102.1 FM   14.7 mi. Signal Strength 5   Saint Paul, MN     Country 
 [BC] [Info]  K273BH (KDWB  102.5 FM   14.4 mi. Signal Strength 1   Fridley, MN     Top-40 
 [BC] [Info]  KMNB   102.9 FM   14.7 mi. Signal Strength 5   Minneapolis, MN     Country 
 [BC] [Info]  K278BP (KFXN  103.5 FM   14.4 mi. Signal Strength 2   Cottage Grove, MN     Sports 
 [BC] [Info]  KZJK   104.1 FM   14.7 mi. Signal Strength 5   Saint Louis Park, MN     Adult Hits 
 [BC] [Info]  KCLD   104.7 FM   61.3 mi. Signal Strength 1   Saint Cloud, MN     Top-40 
 [BC] [Info]  WRXP   105.3 FM   29.3 mi. Signal Strength 2   Cambridge, MN     Sports 
 [BC] [Info]  WGVZ   105.7 FM   14.4 mi. Signal Strength 4   Eden Prairie, MN     Sports 
  [Info]  KLCI   106.1 FM   15.6 mi. Signal Strength 4   Elk River, MN     Country 
 [BC] [Info]  KTMY   107.1 FM   14.0 mi. Signal Strength 4   Coon Rapids, MN     Talk 
 [BC] [Info]  KQQL   107.9 FM   11.7 mi. Signal Strength 5   Anoka, MN     Classic Hits 
 
 [BC] [Info]  WXYG   540 AM   47.4 mi. Signal Strength 2   Sauk Rapids, MN     Adult Album Alternative 
 [BC] [Info]  WREY   630 AM   31.5 mi. Signal Strength 3   Saint Paul, MN     Regional Mexican 
  [Info]  WBHR   660 AM   47.4 mi. Signal Strength 2   Sauk Rapids, MN     Sports 
  [Info]  KFXN   690 AM   10.1 mi. Signal Strength 2   Minneapolis, MN     Asian 
 [BC] [Info]  WDGY   740 AM   37.6 mi. Signal Strength 2   Hudson, WI     Oldies 
 [BC] [Info]  KUOM   770 AM   15.2 mi. Signal Strength 4   Minneapolis, MN  University of Minnesota  College 
 [BC] [Info]  WVAL   800 AM   47.4 mi. Signal Strength 2   Sauk Rapids, MN     Country 
 [BC] [Info]  WCCO   830 AM   1.7 mi. Signal Strength 5   Minneapolis, MN     News/Talk 
 [BC] [Info]  KTIS   900 AM   23.2 mi. Signal Strength 5   Minneapolis, MN  Northwestern College  Religious 
  [Info]  KDHL   920 AM   62.8 mi. Signal Strength 2   Faribault, MN     Farm 
 [BC] [Info]  KTNF   950 AM   20.9 mi. Signal Strength 3   Saint Louis Park, MN     Talk 
 [BC] [Info]  KKMS   980 AM   27.6 mi. Signal Strength 3   Richfield, MN     Religious 
 [BC] [Info]  WCTS   1030 AM   31.5 mi. Signal Strength 4   Maplewood, MN     Religious 
 [BC] [Info]  KTLK   1130 AM   36.1 mi. Signal Strength 4   Minneapolis, MN     Talk 
  [Info]  KYES   1180 AM   46.5 mi. Signal Strength 2   Rockville, MN     Religious 
 [BC] [Info]  KLBB   1220 AM   28.1 mi. Signal Strength 2   Stillwater, MN     Nostalgia 
 [BC] [Info]  WWTC   1280 AM   14.5 mi. Signal Strength 3   Minneapolis, MN     News/Talk 
 [BC] [Info]  WLOL   1330 AM   26.7 mi. Signal Strength 3   Minneapolis, MN     Religious 
  [Info]  KMNV   1400 AM   17.0 mi. Signal Strength 2   Saint Paul, MN     Regional Mexican 
  [Info]  KDIZ   1440 AM   12.6 mi. Signal Strength 4   Golden Valley, MN     Children's 
  [Info]  KMNQ   1470 AM   5.7 mi. Signal Strength 5   Brooklyn Park, MN     Regional Mexican 
 [BC] [Info]  KSTP   1500 AM   19.3 mi. Signal Strength 4   Saint Paul, MN     Sports 
  [Info]  KQSP   1530 AM   26.5 mi. Signal Strength 3   Shakopee, MN     Tropical 
 [BC] [Info]  KYCR   1570 AM   14.5 mi. Signal Strength 3   Golden Valley, MN     Business News 
  [Info]  KPNP   1600 AM   25.9 mi. Signal Strength 2   Watertown, MN     Spanish 
 
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post #9 of 44 Old 01-22-2014, 02:56 PM
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Most of the major TV and FM radio stations in the Twin Cities broadcast from one of three large towers easily visible next to 694 in Shoreview (the two "twins" side-by-side are called the Telefarm Towers while the third one, a little under a mile to the southeast, is known as the KMSP Tower, even though KMSP is one of several TV and radio stations that transmit from the tower).

Anyway, especially strong FM signals can generate interference from second harmonics, or electromagnetic waves that have double the frequency of the original wave. The frequencies used for the VHF TV high-band ("real" channels 7-13) just so happen to correspond almost exactly to double the frequencies in use with the FM radio band. In North America, channel 11, for example, occupies the portion of the electromagnetic spectrum from 198 MHz to 204 MHz. Dividing these frequencies in half means that FM stations between 99 MHz and 102 MHz could create second harmonics that produce interference within the 6 MHz bandwidth of channel 11. That chart from Radio-Locator lays out the likeliest potential culprits: KSJN/99.5 MHz, KFXN/100.3 MHz, and/or KDWB/101.3 MHz, all of which transmit from the KMSP Tower.

Theoretically by operating on channel 9, KMSP should be subject to the same process, only with FM radio frequencies between 93 MHz and 96 MHz since channel 9 runs between 186 MHz and 192 MHz. That you are not experiencing similar problems with KMSP could come down to any number of factors. Put simply, each specific situation is unique.
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post #10 of 44 Old 01-22-2014, 03:26 PM - Thread Starter
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Originally Posted by agus0103 View Post

Most of the major TV and FM radio stations in the Twin Cities broadcast from one of three large towers easily visible next to 694 in Shoreview (the two "twins" side-by-side are called the Telefarm Towers while the third one, a little under a mile to the southeast, is known as the KMSP Tower, even though KMSP is one of several TV and radio stations that transmit from the tower).

Anyway, especially strong FM signals can generate interference from second harmonics, or electromagnetic waves that have double the frequency of the original wave. The frequencies used for the VHF TV high-band ("real" channels 7-13) just so happen to correspond almost exactly to double the frequencies in use with the FM radio band. In North America, channel 11, for example, occupies the portion of the electromagnetic spectrum from 198 MHz to 204 MHz. Dividing these frequencies in half means that FM stations between 99 MHz and 102 MHz could create second harmonics that produce interference within the 6 MHz bandwidth of channel 11. That chart from Radio-Locator lays out the likeliest potential culprits: KSJN/99.5 MHz, KFXN/100.3 MHz, and/or KDWB/101.3 MHz, all of which transmit from the KMSP Tower.

Theoretically by operating on channel 9, KMSP should be subject to the same process, only with FM radio frequencies between 93 MHz and 96 MHz since channel 9 runs between 186 MHz and 192 MHz. That you are not experiencing similar problems with KMSP could come down to any number of factors. Put simply, each specific situation is unique.

 

Great info!  I swung by Radio Shack over lunch and picked up an FM Trap and will throw it on when I get home from work.  Fingers crossed!

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post #11 of 44 Old 01-22-2014, 06:01 PM - Thread Starter
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Ok, so FM Trap is in...tuned into channel 11 and so far no pixelation but I've only been watching for about 10min.  I really hope this is the trick.  I'm stressing out watching right now, I know I' going to be so mad if it's still happening.

 

I'll check in later tonight.

 

Thanks to everyone for their advice and knowledge.

 

One more quick question.  My Vizio has been fine this entire time and if there is interference with the LG, wouldn't there be interference with the Vizio since it's all coming from the same antenna?  Or are different tuners better/worse at filtering out unwanted signals?

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post #12 of 44 Old 01-22-2014, 07:26 PM - Thread Starter
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Well, I'm back with some okay news and bad news.  First, with the bad...it's probably not FM interference as the pixelation was still happening with the FM trap.  

 

Now, with the okay news.  I've been doing the interference finding trick with an AM radio; set to a low frequency and it'll make a bunch of static when it's around something that could cause interference.  With that being said, I've found a few things and ruled out out a few things.

 

Another question.  Is there anyway the outlet that the TV is plugged into could be causing this?  Reason I ask is because the radio is making the static noise when at that specific outlet...moreso than other outlets.  Second reason for me asking, if you'll refer to my 1st post you'll see that I brought in another TV to test the coax cables and didn't see any interference with that.  Key point behind that is that this other TV was plugged into a different outlet.

 

It's frustrating, but I still feel like I have options...so that's good.

 

What are your guy's thoughts?

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post #13 of 44 Old 01-22-2014, 07:47 PM
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Pretty good sleuthing there. I'd begin to suspect something else plugged into that breaker circuit. A motor most likely. I did experience a similar kind of thing in an office setting.. A user brought in a desktop aircleaner. Six months later her devices, first a printer then an older Hayes modem started acting strange. The printer was on a parellel port and would intermittently print garbage. A sharp impact on the desk would make things okay for a second and then garbage again. Then the monitor, the final clue, sitting right next to the air cleaner started getting wavy lines in the display but quit with a sharp knock on the desk. As luck would have it, while moving the monitor, I realized the aircleaner was barely turning and the case was HOT. Unplugging the thing, all went away. It was also plugged into the power strip for the whole desk, computer equipment too.
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post #14 of 44 Old 01-22-2014, 07:59 PM - Thread Starter
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Originally Posted by mjd420nova View Post

Pretty good sleuthing there. I'd begin to suspect something else plugged into that breaker circuit. A motor most likely. I did experience a similar kind of thing in an office setting.. A user brought in a desktop aircleaner. Six months later her devices, first a printer then an older Hayes modem started acting strange. The printer was on a parellel port and would intermittently print garbage. A sharp impact on the desk would make things okay for a second and then garbage again. Then the monitor, the final clue, sitting right next to the air cleaner started getting wavy lines in the display but quit with a sharp knock on the desk. As luck would have it, while moving the monitor, I realized the aircleaner was barely turning and the case was HOT. Unplugging the thing, all went away. It was also plugged into the power strip for the whole desk, computer equipment too.

 

I can't really think of any motors plugged in anywhere in the house.  However, the culprit socket is directly by the front door where the doorbell is and I recall seeing notes about doorbells causing interference.

 

If I do find out that it's that outlet that's the problem, could I run an extension cord to keep the TV in the same spot?  Or is it the physical location of the TV that's the issue?

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post #15 of 44 Old 01-23-2014, 12:30 AM
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I can't really think of any motors plugged in anywhere in the house.  However, the culprit socket is directly by the front door where the doorbell is and I recall seeing notes about doorbells causing interference.

If I do find out that it's that outlet that's the problem, could I run an extension cord to keep the TV in the same spot?  Or is it the physical location of the TV that's the issue?

I'd try the easiest first with the extension cord.
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post #16 of 44 Old 01-23-2014, 07:09 AM - Thread Starter
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I'm going to pick up an extra extension cord this afternoon.

 

Now, onto my next theory...and one that I'm pretty confident if I do say so myself :)

 

Ceiling fan!  It's a remote controlled fan and I believe the receiver for it is hardwired into the same circuit that the TV has been plugged into.  Since the fan uses RF frequency, this is a likely culprit.  The AM radio goes nuts in that area when the fan light is on.

 

Also, check out #2 under notes on page 3: http://www.hunterfan.com/uploadedFiles/Support/Owners_Manuals_and_Parts_Guide/41316(1).pdf

 

Now, IF this is the problem, here are a couple of questions:

- Would I be experiencing this issue all the time because the fan receiver has constant power being hardwired and all?

- Is this type of interference "through the air" meaning I'd have to physically move the TV?  Or is it being transmitted through the outlet?  If it's through the outlet, I can run an extension cord to the TV but would I not be able to have anything else plugged into the 'culprit' outlet?

 

Thanks all!  I'm getting close and the gf thinks I'm nuts walking around pointing an AM radio at electronics =/

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post #17 of 44 Old 01-23-2014, 11:10 AM
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Receivers don't usually cause interference through the air or over the power line. The remote is the transmitter and could cause interference through the air, only when it is being used to control the fan or light. The AM radio could be going nuts when the fan light is on because it is a CFL or an incandescent that is being dimmed. Light dimmers can cause interference through the air and over the power line, especially when they are not up full. Some CFLs may be able to cause interference through the air or over the power line.
I make it a point to always document every single fixture/outlet/device as to what breaker it is on.
I once had trouble receiving one tv station just on one tv and it was because my wireless surround speaker tramsmitter was too close to the stand-alone tuner. The interference was through the air.
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post #18 of 44 Old 01-23-2014, 01:01 PM - Thread Starter
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Quote:
Originally Posted by dbdoc View Post

Receivers don't usually cause interference through the air or over the power line. The remote is the transmitter and could cause interference through the air, only when it is being used to control the fan or light. The AM radio could be going nuts when the fan light is on because it is a CFL or an incandescent that is being dimmed. Light dimmers can cause interference through the air and over the power line, especially when they are not up full. Some CFLs may be able to cause interference through the air or over the power line.
I make it a point to always document every single fixture/outlet/device as to what breaker it is on.
I once had trouble receiving one tv station just on one tv and it was because my wireless surround speaker tramsmitter was too close to the stand-alone tuner. The interference was through the air.

 

Good info, thanks!  Here are some facts:

- Pixelation happens on the TV whether the fan/fan lights are on or off.  Whatever is causing the issue is constant.

- The lights in the fan are incandescent and there is a dimmer on the remote that I believe is not turned all the way up.

- The AM radio goes nuts near the 'culprit' outlet in the following scenarios:

            - Fan light is on, nothing plugged into the outlet.

            - Fan light is on, something plugged into outlet.

            - Fan light is off, something plugged into outlet.

- The AM radio is quiet when the fan light is off and nothing is plugged into the outlet.

 

I'm thinking there is something on that circuit that is causing interference in the line.  What are some common causes of that?

 

Over lunch, I ran out and grabbed 2 different surge protectors to test a couple of options:

- A short cord to plug into the 'culprit' outlet.  This surge protector has RFI/EFI filtration to clean up the signal.

- A longer cord one to run to an outlet on a different circuit.  This one also has RFI/EFI filtration.

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post #19 of 44 Old 01-23-2014, 07:24 PM - Thread Starter
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Crap - So none off that worked.

 

I'm not giving up though!  I shut off each breaker in the house to see if the noise on the AM station would go away.  Oddly enough, I narrowed it to the basement where the flawless Vizio is.  Waved the radio around and where my wifi modem/router is plugged in just about blew up my radio!  What can you guys tell me about that?  Is it the wifi signal?  Power supply?

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post #20 of 44 Old 01-23-2014, 07:55 PM
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With that tvfool report, I wonder if you even need an amp. I would start with the basics first. Use your small tv in the garage rafters and make sure your antenna is aimed optimally. Height is important.

Have you tried just running directly form the antenna to the LG? Try that as a test. eliminate the splitters by joining the coaxes together with f-couplings, and just run into only the LG.

If you see the LG is working fine, then add just a 2 way splitter, and split to the Vizio and LG. Also make sure the splitter is rated up to at least 900MHZ. Some of the older ones only go up to 500 Mhz.
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post #21 of 44 Old 01-23-2014, 08:56 PM - Thread Starter
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Ok, back to the basics!  I went into the garage and connected the antenna directly to the LG.  Watching channel 11 as I type...

 

Here's the thing, if I split the coax at the downlead and have one line going straight to the LG and another to a splitter for the rest of the three lines (this is how I had it when I first set it up) then the Vizio doesn't get a great signal because it's on the other end of the line that's been split once and again three more ways.  So I'd need the amped distributor for there.  Here is the 2 way splitter was initially on the downlead...I have a couple of these laying around:

 

I guess I could just hook up ONLY the leads coming into the house that the LG and Vizio are utilizing and then cross the bridge of additional TVs when I need to.

 

FYI - In the 15 minutes or so that it took me to post this...no pixelation!

 

Would the drop from only using a 2 way splitter cause enough loss to cause the pixelation I was seeing to begin with (when the 2 way splitter was on the downlead)?

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Well, it pixilated again coming straight from the antenna.....but it was less than when it was hooked up to the amplified splitter.  With that being said, maybe I have too strong of a signal directly from the antenna?  Can that happen?

 

So, with that...I went back out and put in the above mentioned 2 way splitter between the antenna and 4 way distributed amplifier and am monitoring again wondering if the -3.5db loss deadens the signal enough to get rid of the pixelation altogether.  It looks like it didn't...well either that or I need signal strength somewhere between the direct antenna and the -3.5db loss.  Could it be that finiky?

 

I'm tempted to order an attenuater...but how much of a db loss should I be aiming for?  I'm seeing anywhere between a 3db loss to a 16db loss.

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Quote:
Originally Posted by WRX1986 View Post

Ok, back to the basics!  I went into the garage and connected the antenna directly to the LG.  Watching channel 11 as I type...

FYI - In the 15 minutes or so that it took me to post this...no pixelation!

Would the drop from only using a 2 way splitter cause enough loss to cause the pixelation I was seeing to begin with (when the 2 way splitter was on the downlead)?

OK, great. So no pixilation in the LG.

What happens when you hook up ONLY a 2 way splitter? ( with no 4way amplified splitter). With each output going to 1 TV.

The other thing you can try is putting the amplified splitter close to the antenna, as that where it should go anyway.

The way you had it set up before, the signal was going through a splitter, than to the amp/splitter. By the time the signal got amplified, it lost signal and gained more noise as it traveled through the coax.
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Go back to your original description of WHEN the pixelization occurs:
Quote:
The pixelation really only happens at the very when one commercial transitions into another, commercial into show, or show into commercial.

If this is indeed the case, you are wasting your time with the reception side of the system. There is no difference in the signal in the air from the station at those times (other than the digital data that is encoded in the signal) than at any other so there is no possibility that it's a reception problem.

For whatever reason, it's the tuner in the TV set that is causing the problem.
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post #25 of 44 Old 01-24-2014, 06:49 AM
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Quote:
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Go back to your original description of WHEN the pixelization occurs:
If this is indeed the case, you are wasting your time with the reception side of the system.

That's not true. He already confirmed that the LG is fine if he runs from the antenna directly to the LG, so it must be related to the reception.
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post #26 of 44 Old 01-24-2014, 07:06 AM - Thread Starter
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A few things:

- The LG isn't 100% ok running just from the antenna...just less pixelation.  This has me feeling I'm going in the right direction by knocking the signal down.

- Pixelation occurs MOSTLY between commercials or coming back to a program.  Not always though...it sometimes happens in the middle as well.

- The amped splitter is only about 25ft from the antenna.

 

Questions:

- Can a signal be too strong from the antenna with NO amps attached (pre or distribution)?

- Is it worth trying an attenuator in this situation?  I have a regular 4 way (-7db) splitter laying around that I might try to hook up instead of the 2 way to see if that knocks the signal down a bit and cleans everything up.

- Is it possible for the signal to be so finniky that straight from the antenna is too strong but after a 2 way splitter is added in (-3.5db loss) then it's too weak?

 

None of the lines are overly long.  From the antenna to the LG & Vizio is probably only about 50ft of coax...maybe a bit more to the Vizio.

 

EDIT: While running out to start the car, I threw the 4 way splitter on in place of the two way just for kicks and giggles.  I've only got a little bit of time to watch some more TV though...until probably Saturday :(

 

EDIT #2: ProjectSHO89, thanks for the input but I might have some evidence that proves it isn't the tuner within the TV.  Before I put up the antenna in the garage, I had rabbit ears that didn't cause this problem at all.  One would think if the tuner is at fault, then it would be consistent across anteannas.  Keep the ideas coming!  I'll rule out as much as I can!

 

Again - Thanks for everyone's help!!!!

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Tv tuners have around a 30 db range of acceptible signal levels, from +15dbmv to -15dbmv. You have an amp and some splitters for attenuators to vary signal levels. Use them to see if the problem is level related.
Troubleshooting with test equipment like a signal level meter (SLM) can be frustrating enough, but without can be very time consuming. Multipath interference caused by wind blowing tree leaves etc can lead to changing conditions, making it harder to make sense out of tests that you run.
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Those appear to be CABLE TV signal levels....OTA ATSC typically has 50-70 dB of Spurious Free Dynamic Range (SFDR) with judicious CHOICE of Preamp (which MAY require a small amount of attenuation on it's input) and a "typical" tuner sensitivity of about -85 dBm (-38 dBmV):
http://photos.imageevent.com/holl_ands/files/ota/DTV%20Preamp%20Signal%20Overload%20Calculator%20-%20RevM.xls
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post #29 of 44 Old 01-25-2014, 11:48 AM - Thread Starter
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Quote:
Originally Posted by holl_ands View Post

Those appear to be CABLE TV signal levels....OTA ATSC typically has 50-70 dB of Spurious Free Dynamic Range (SFDR) with judicious CHOICE of Preamp (which MAY require a small amount of attenuation on it's input) and a "typical" tuner sensitivity of about -85 dBm (-38 dBmV):
http://photos.imageevent.com/holl_ands/files/ota/DTV%20Preamp%20Signal%20Overload%20Calculator%20-%20RevM.xls

 

I'm sorry, I don't really understand what you're saying here.  I'm completely new to this, so bear with me.  Are you saying that I'd be getting signal overload to the LG?

 

To continue with the updates on my testing; last I left it was using a 4-way splitter to knock the signal down -7db to the LG.  I'm still getting some pixelation/blocking...but it appears to be less than when I was only using the 2-way (-3.5db) splitter, so I'm taking that to mean that I'm headed in the right direction.

 

I'm thinking of ordering a pack of -3db attenuators from Amazon and just add them until the signal is no longer overloaded.  I've ready how you can daisychain them together, is that right?

 

Here's what I'm thinking of ordering: http://www.amazon.com/CHANNEL-PLUS-2503-10--Line-Attenuators/dp/B0006PIR8Q/ref=sr_1_12?s=electronics&ie=UTF8&qid=1390538722&sr=1-12&keywords=inline+attenuator

 

Has anyone else experienced this type of overload without an amp?

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post #30 of 44 Old 01-25-2014, 12:31 PM - Thread Starter
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I just dawned on me that I have the extra equipment lying around to connect the 2 way splitter first and then added the additional 4 way splitter onto the LG line.  So, right now I'm running a signal loss of about -10.5db.  If this works, then I can just order a -7db attenuator if they make it...right now the closest I'm seeing is -6db.  Or do I even need to order one?  Are splitters and attenuators basically the same thing, but just look different?

 

I will say, the testing on this is nice because to check my results I just have to plop my butt on the couch and watch TV :)

 

UPDATE: Very little pixelation at the 10.5db loss (2way into 4way).  Instead of the attenuator link I posted above, I ended up buying on each of a 6db, 10db, 12db, and 16db attenuator.  I'll find the right one that works...I'm just happy I've found the source of the issue!

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