Harrisburg, PA: Panasonic Plasma \ VHF OTA observation and troubleshooting - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 17 Old 09-15-2016, 07:08 AM - Thread Starter
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Harrisburg, PA: Panasonic Plasma \ VHF OTA observation and troubleshooting

http://www.tvfool.com/?option=com_wr...e2cbf580bcdce7

I've been troubleshooting an OTA issue and I'd like to share my observations to potentially help others out.

I will update this post once I confirm the problem and come up with a resolution.

Here's a quick overview of my layout.

Wineguard-1080 roof mounted antenna
3 way even distribution Monster splitter
Quad-coax cable runs
No amps or boosters

Anyway, my OTA experience has been very positive (all broadcasts are within 40 miles)...

With the exception of a single and my only VHF channel. And I'm only having issues with this VHF channel on a single TV, which happens to be my Panasonic TC-P60ST50 Plasma. I'm seeing very sporadic signal strength, and it not getting above 50%

My other TV, a Samsung LCD doesn't have this problem, in fact the signal is nearly perfect. To rule out the cable run and connections I moved the Samsung to the location of the Plasma and the signal still remained perfect.

My first thoughts were (and still could be) the Panasonic Tuner with VHF stations. I upgraded the firmware to the latest version which didn't make a difference. I couldn't find a separate Panasonic Tuner firmware update though I saw that mentioned before.

So I have a few options and a few other things to try...

1) Connect the Samsung back up, in front of the Plasma which will also be turned on, and determine if the Plasma TV itself is causing interference with the VHF transmission (which are more prone to interference than UHF).
2) Attempt to manually tune the UHF broadcast of this same channel (NBC). The UHF broadcoast is in-line and in-range of the other channels that I'm picking up so I'm not quite sure why it's not getting auto programmed.
3) Add a digital tuner to bypass the panasonic one (have not looked into this at all).
4) Stream this channel

Any thoughts or feedback?

I will figure this out... Sunday Night Football depends on it

Last edited by DrDon; 09-15-2016 at 08:12 AM.
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post #2 of 17 Old 09-15-2016, 07:20 AM
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Please follow the sticky at the top of this forum and PM Dr. Don to add a link to your TV Fool report. Also please tell us which (real) channel is the UHF version of your VHF channel. Sometimes it's not obvious.
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post #3 of 17 Old 09-15-2016, 07:27 AM
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You'll also want to edit in model numbers. Newer sets have better tuners. Read the PM I sent you.

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post #4 of 17 Old 09-15-2016, 07:55 AM - Thread Starter
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Quote:
Originally Posted by Calaveras View Post
Please follow the sticky at the top of this forum and PM Dr. Don to add a link to your TV Fool report. Also please tell us which (real) channel is the UHF version of your VHF channel. Sometimes it's not obvious.
Working on getting my original post updated.

Real channel is 49 (virtual 8.1)
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post #5 of 17 Old 09-15-2016, 08:13 AM
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Link and one model number added to first post. Title edited. May move to existing Harrisburg thread, soon. The guys there know more about the lay of the land than the rest of us.

Walking the fine line between jaw-dropping and a plain ol' yawn.
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post #6 of 17 Old 09-15-2016, 08:24 AM - Thread Starter
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Quote:
Originally Posted by DrDon View Post
Link and one model number added to first post. Title edited. May move to existing Harrisburg thread, soon. The guys there know more about the lay of the land than the rest of us.
Thanks for the edit.

This is not a location issue. I've narrowed it down to a Panasonic tuner or Plasma interference issue with a VHF channel as you can see in my original troubleshootin (same VHF channel comes in perfectly on the Samsung LCD)
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post #7 of 17 Old 09-15-2016, 08:44 AM
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Until I see your TVFool Report, a few thoughts:

1) W-G 1080 has very NEGATIVE Gain in Hi-VHF Band, so I'll have some recommendations on alternative improvements (incl. DIY):
http://www.winegarddirect.com/pdf/hd-1080-spec.pdf

2) Tuners in different TV's vary very little wrt Sensitivity....but vary quite a bit wrt Interference Susceptibility to both OTA Signals and Local Man-Made Interference.

3) Microwave Ovens, Overhead Fans, Light Dimmers as well as LED/LCD and other Fluorescent Lights can generate quite a bit of interference in Hi-VHF Band and not so much in UHF Band. So try switching various lights on and off to see if there is any difference. BTW: RFI/EMI Filters on Power to HDTV may NOT be very effective in reducing coupling to your ANTENNA via Direct Radiation....best to solve the problem at the SOURCE.

4) Other Electronic Equipment, WallWart Power Supplies/Chargers, Alarm Clocks, etc. (esp. Cheap Imports) can ALSO generate Interference, which can be coupled to HDTV via direct radiation as well as via Power Circuits (separate circuit breakers have less coupling than if on same circuit breaker). So try with ALL other Electronic Equipment turned off (incl other HDTV) and turn on each piece of equipment while watch for differences.

5) Power Lines to the house [esp. if overhead rather than underground] can ALSO be carrying Interference, which will be different at different outlet locations. Only a FEW Surge Protector Power Strips actually include EFFECTIVE RFI/EMI Filters, such as following. ISOBLOK plugs into the WALL SOCKET, thereby protecting EVERYTHING on that and (to some degree) nearby Wall Outlets, whereas ISOBAR products are the usual Power Strips:
https://www.tripplite.com/isobar-2-o...ight~ISOBLOK20
https://www.tripplite.com/isobar-8-o...s~ISOBAR8ULTRA [Just one Example]
https://www.tripplite.com/shared/lit...-953229-EN.pdf

Belkin also makes some Power Strips with a lower level of RFI/EMI Filtering: [See fol. Examples] as well as those that are just as effective as the Tripplite Units (for a price):
http://www.staples.com/Belkin-6-outl...roduct_1948948
https://www.amazon.com/Belkin-BE1122.../dp/B000J2EN4S
https://www.amazon.com/6-Outlet-Surg...3MHXXPNDAMFP30

6) Cable Feed to house [for say Internet] can ALSO be carrying Interference, so disconnect at the house entry point and see if there is any difference. There are CATV Ground Isolators that can be used to solve this problem. [Do NOT confuse FULL BAND CATV Isolators with Narrow Bandwidth VIDEO Isolators typically used on output of Remote Cameras].

I recommend AGAINST using "Surge Protectors" built into Power Strips for COAX, PHONE or Ethernet Cables. The LAST thing you want near your Power Strip is something laden with External Interference (esp. Cable or OTA Coax)....and VICE VERSA. There are INDIVIDUAL Coax Ground Isolation Filters.....and Surge Protectors...but AVOID typical MOV type, cuz they DEGRADE RF signals as they absorb Voltage Spikes. Fol. Holland CISP Ground Isolator plus Sidactor Surge Protector does NOT degrade. Can also use Gas Tube type Surge Suppressors, but they have much higher Breakdown Voltages:
https://www.wiredathome.com/holland-...ike-protection
http://www.hollandelectronics.com/ca...Protection.pdf

Last edited by holl_ands; 09-15-2016 at 09:05 AM.
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post #8 of 17 Old 09-15-2016, 09:04 AM
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Looking at the terrain map for real 8, you're shadowed from the transmitter by two mountains. Crappy signal to begin with. The fact the FCC approved a translator for WGAL tells me a LOT of people have reception issues in your area. You may be luckier than you think that you have one set that'll grab real ch 8.

So, yeah. It's quite likely an issue you wouldn't have if you lived in Lancaster.

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Last edited by DrDon; 09-15-2016 at 09:07 AM.
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post #9 of 17 Old 09-15-2016, 09:11 AM
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CECB (Coupon Eligible Converter Boxes) came out in 2008, FORCING the industry to meet some very specific 8VSB Performance Specs, incl. nearly 50 "worst case" Multipath Field RF Captures, with percentage "passed" dramatically improving compared to 2005/2006 DTV/STBs that were tested earlier [a perfect score is believed to be impossible, some are WAY too bad].

Pretty much ALL Tuners built since about 20092010 (and a FEW from 2008) are about as good as it's going to get wrt meeting those non-mandatory specs derived from ATSC A/74 Guidelines. So, 8VSB performance pretty much MAXED OUT quite some time ago, although there ARE some differences in how they handle Overload [incl. FM Band signals] and 3rd Order Intermods NOT stipulated in A/74. Charles Rhodes [TV Technology Magazine] measured these as being WORSE for Double-Conversion "Silicon" Tuners that have become much more popular since introduced in SOME CECB's.

Unfortunately mfrs don't usually SAY whether they are using the now popular (i.e. lower cost), so-called "Silicon" Tuner that typically "forgot" to include a Varactor Tuned, Narrow Bandwidth Filter on it's Input like all Super-Heterodyne Tuners, to attenuate strong signals 20-30+ MHz away from the Desired Frequency. And universally mfrs do NOT tell us how WELL their Tuners perform.....Specs??? We don't NEED no STINKING Specs......

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post #10 of 17 Old 09-15-2016, 09:40 AM - Thread Starter
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Thanks for all of the feedback so far.

Quote:
Originally Posted by DrDon View Post
Looking at the *LINK REMOVED* for real 8, you're shadowed from the transmitter by two mountains. Crappy signal to begin with. The fact the FCC approved a translator for WGAL tells me a LOT of people have reception issues in your area. You may be luckier than you think that you have one set that'll grab real ch 8.

So, yeah. It's quite likely an issue you wouldn't have if you lived in Lancaster.
Thanks. What baffles me is that the TV that is picking up real 8 has a 5\5 signal and I haven't seen it drop\distort once. Though I don't know how much I can trust the signal meter as I haven't seen it fluctuate at all.

A 5\5 steady signal from the Samsung vs the 0-30% signal from the Plasma from the same exact COAX run is perplexing to me.
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post #11 of 17 Old 09-15-2016, 10:23 AM
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Until I see your TVFool Report, a few thoughts:
He added the tvfool report link to his first post:

http://www.tvfool.com/?option=com_wr...e2cbf580bcdce7

According to rabbitears.info and wiki WGAL has two transmitters, one on VHF and one on UHF, both with the virtual channel number of 8.1.

http://www.rabbitears.info/market.ph...&callsign=wgal

http://www.rabbitears.info/tvq.php?r...ms&facid=53930

https://en.wikipedia.org/wiki/WGAL

It might be a PSIP (Program and System Information Protocol) problem that confuses the tuner, since they both have the same virtual channel number which the TV displays.
https://www.google.com/?gws_rd=ssl#q=psip

Do your TVs show the frequency of the real channel in the menu?

Channel 8 has a center frequency 183 MHz; channel 49 is 683 MHz.
https://en.wikipedia.org/wiki/North_...on_frequencies
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post #12 of 17 Old 09-15-2016, 11:44 AM
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Quote:
and determine if the Plasma TV itself is causing interference with the VHF transmission (which are more prone to interference than UHF).
Yes, that is quite possible.
https://www.google.com/?gws_rd=ssl#q...+vhf+reception

Is the coax grounded?

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post #13 of 17 Old 09-15-2016, 03:40 PM
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Quote:
2) Attempt to manually tune the UHF broadcast of this same channel (NBC). The UHF broadcoast is in-line and in-range of the other channels that I'm picking up so I'm not quite sure why it's not getting auto programmed.
Does either TV get WGAL on real channel 49?


If not, I suggest an antenna with more gain.

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post #14 of 17 Old 09-15-2016, 05:41 PM
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Winegard used to give gain figures for its antennas in dBd. This is what Solid Signal shows for the HD-1080:
http://www.solidsignal.com/pview.asp?p=hd-1080

Winegard now uses dBi for the HD-1080 in its spec sheet:
http://www.winegard.com/kbase/uploads/HD-1080.pdf


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post #15 of 17 Old 09-19-2016, 01:07 PM
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Quote:
Originally Posted by kaptain02 View Post

2) Attempt to manually tune the UHF broadcast of this same channel (NBC). The UHF broadcoast is in-line and in-range of the other channels that I'm picking up so I'm not quite sure why it's not getting auto programmed.
Try deleting the NBC after the auto scan before trying to manually programming 49. As suggested by Rabbit the PSIP is the same for both channels. I think they refer to channel 49 as a “replacement translator”. All of my Dish Network VIP tuners will only see either 8 or 49 but not both at the same time and since it scans 8 first it overlooks 49. All of my other tuners can see both channels at the same time.
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post #16 of 17 Old 09-19-2016, 07:55 PM
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VHF is more subject to noise and interference than UHF, and the plasma TV likely puts out more electrical noise than the Samsung LCD. However, the Panasonic ST50 otherwise has a very sensitive tuner, so the solution would be to have a higher gain VHF antenna and a good preamp if needed to overcome the noise and interference. Panasonic plasmas previously had weaker tuners, but the more recent versions such as ST50 and ST60 had very good tuners. I have a ST60 and the tuner will lock weak signals down to 11%. Plus excellent picture; too bad they stopped producing plasma.
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post #17 of 17 Old 09-21-2016, 05:11 AM - Thread Starter
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I figured this out.

I ran another auto-program and when I went into the manual channel setup I noticed that 8.1 was listed twice. This may have been the case the entire time but this is the first time I noticed it.

Anyway, one was added and the other was not. I reversed the selections (in the Panasonic setup change the 'Add' field to yes or no), and now 8.1 comes in perfectly steady with a 80%+ signal.

So what was happening is that it was indeed adding both the VHS and UHF signal and keeping them listed under the same virtual channel which was listed twice. I suspect, from Tylers comment, is that the panasonic tuner is actually very good since it was able to also pick up the VHS channel... The reason the samsung has no issues is because it was only picking up the UHF signal the entire time.

Thanks for all of the feedback
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