Your Universal Remote Control Center
RemoteCentral.com
HDTV Reception Forum - View Post
Previous section Next section Previous page Next page Up level
Up level
The following page was printed from RemoteCentral.com:

Login:
Pass:
 
 

Page 1 of 2
Topic:
New TV = poor OTA reception
This thread has 15 replies. Displaying all posts.
Post 1 made on Monday December 5, 2011 at 14:24
purtypitcher
Lurking Member
Joined:
Posts:
December 2011
5
Recently had a new Panasonic TC-P50S30 plasma delivered. My over the air reception is terrible with it, and that's what I wanted it for. It is replacing a 30 year old 27" TV with a Digital Stream converter box that has great reception of all local channels.
 
The Panasonic only gets four of the six local channels, and only one is good, the others, iffy. If I move my (indoor) antenna around, I can usually get these four to work, but I have to move the antenna each time I change the channel. It is a small Philips omni-directional antenna, I don't have the model number handy, it is not powered. All six channels are UHF true frequency.
 
If the signal strength meter on the Panasonic shows 80% I will get a choppy picture. If the signal strength meter shows 85% the picture is "mostly" fine with almost no glitches. 90% or above- totally glitch free. If the signal is 75 or below, I get nothing but digital junk, or it goes to black. The four channels that I can receive have varied all around those numbers in my testing. The other two local channels show no signal at all when I tune to their channel.

I am less than four LOS miles from three of the towers, NBC, CBS, ABC affiliates. CBS scores 70-80% on the TV's meter but I only get pixel junk. According to TV Fool, this one should be my strongest signal. ABC shows 90-100 on the meter and is great. NBC runs around 80-85 and has numerous pixel hiccups.

TV Fool shows five of the six local channels in their "green" (easiest to receive) category based on my location information. The sixth one is actually 46 miles away (so actually not local), and is rated "yellow", but the old TV/converter box gets it fine with the Philips indoor antenna.

I'm perfectly willing to look at better antennas, but I'm wondering about those signal strengths on the Panasonic meter. It seems to me that a 70% or above meter reading ought to be plenty to get over the cliff. It seems to me that a CBS affiliate at 3.3 miles from my house ought to come in fine with a coathanger and aluminum foil. The cheapo digital-analog converter works fine with my old TV on all channels with no antenna adjustment, even the one that is 46 miles away.

I've got an email into Panasonic but was hoping to get some expert opinions here as well. Thanks.
Post 2 made on Monday December 5, 2011 at 16:10
Nueatit
Long Time Member
Joined:
Posts:
August 2008
148
Some tuners are better at rejecting multipath and reflections, you mentioned moving the antenna changes things, this points to this problem.

Items to know so we can help more:

Are all channels in the same directions
Are the close frequency spaced eg. chn 38, 40 or?
Are you in an apartment/condo?
Are you blocked by other structures, trees etc.
Are you limited to an indoor antenna only?

More ifno, please!
Post 3 made on Monday December 5, 2011 at 18:00
hd fan
Long Time Member
Joined:
Posts:
March 2006
425
Other than the conector of the antenna got broken while changing from converter to TV or maybe you did not screw it in properly at the TV I see no reason why the new panasonic (one wold assume it uses latest generations ATSC tuners therefore better at rejecting multipath intyerference) would not perform either equally or even better. I am interested in what Panasonic might say when you tell them that the old converter box works better.

Some TV's like the Sony's indicate also the SNR levels , they should be above 15 db for a carrier lock , I wonder if the Panasonic also has that feature in the signal level screen.
Post 4 made on Monday December 5, 2011 at 19:04
NFASTRO
Long Time Member
Joined:
Posts:
October 2006
130
Yes that is certainly frustrating. What that is showing is that the cheapo digital converter has a better tuner than the Panasonic. I would really go after Panasonic. If its still within the return period, i would return it and try an LG or Samsung or other brand.
There is a possibility that the tv tuner is overloaded but then again you should be receiving the weaker stations.

You dont mention where you are located... I assume you are in Buffalo. Can you get CH23 CW from Grand Island. It is the easiest for me to get all the way from Toronto with a simple non-amplified antenna.
Post 5 made on Tuesday December 6, 2011 at 09:38
Nueatit
Long Time Member
Joined:
Posts:
August 2008
148
Just because a tv is newer does not mean that the tuner part is better, I also have an older 4 year set top box, more indicators for signal strength etc than my brand new 48 inch 1080p tv, the set top receives chn 36 50% of the time (even shows chn 11 at 49% signal but multipath is killing it 90% of the time) and the new tv shows 0% for both chns. All on the same antenna, rf amp and splitter.

So, in my opinion, newer is not always better, its sometimes how much one pays for the item.

Comparing side by side is the best without having expensive test gear.
OP | Post 6 made on Tuesday December 6, 2011 at 09:43
purtypitcher
Lurking Member
Joined:
Posts:
December 2011
5
Thanks for the replies. I've still got over two weeks of return option, so hopefully can get this figured out. More info:

I am in Lexington, KY. TV is in 1st floor of my house, antenna about five feet off the floor. Some larger trees around, but no big buildings. Looking at channel frequencies reveals some very close numbers, maybe the Panasonic has poor selectivity. From TV Fool:

WKYT-CBS, Real channel: 36, 1000Kw, Distance 3.3 miles, azimuth 84º= nothing but pixelation, unuseable
WTVQ-ABC, Real channel: 40, 635Kw, Distance 3.7 miles, azimuth 91º= 100% signal strength, perfect picture
WLEX-NBC, Real channel: 39, 475Kw Distance 3.7 miles, azimuth 91º= ~85-90% signal, a few occasional pixel burps
WDKY-FOX, Real channel: 31, 1000Kw, Distance 13.1 miles, azimuth 144º= can't remember signal strength, but picture is good, very minor pixel burps
WKLE-PBS, Real channel: 42, 45.8Kw, Distance 13.1 miles, azimuth 145º= black screen, no signal on meter
WUPX-IND, Real channel: 21, 719Kw, Distance 46.1 miles, azimuth 101º= black screen, no signal on meter

So, WTVQ and WLEX appear to be on the same tower, with adjacent frequencies, but I can get both of them. WKYT is not far away from those two, has more power, is not adjacent channel, and I only can get pixels.

I don't think I'm overloaded, and I'll try hooking up the cheapo converter box again when I get home to see if it still works. Also, my next door neighbor said we can hook up my cheap Philips antenna to his TV and see what he gets on his brand new Vizio TV (he is on cable, so has never tested for OTA reception).

In researching TVs, it never even occurred to me to look at tuner sensitivity, figuring anything would be better than my cheap converter box/old TV setup. I used to be all over that spec for FM radio, and in fact am still running an NAD 7400 receiver, which, according to Leonard Feldman from the old Audio magazine, had the best tuner sensitivity of any tuner he had ever tested up to that time (mid 1980's). It is still a fantastic tuner/receiver.

Haven't heard back yet from Panasonic. I'll be contacting Best Buy as well. Heh, thought I was just going to unplug the old TV, plug in the new, and be done with things.......right.
Post 7 made on Tuesday December 6, 2011 at 12:20
Nueatit
Long Time Member
Joined:
Posts:
August 2008
148
Interesting, see what your old setup box gets on TV vs new, to me it looks like a possible local overload (on some tv tuners, signal actually shows a drop even tho it is high) from the chn 36 with reflections being stronger.

The tv set I have is the Vizio too, it is one of the better ones but still limited in the setup showing only rf signal strength, multi-path acceptable but not as good as my set top ZD500.

Best omparison, your set top and the Panasonic side by side, same cable lenth, antenna etc.

Another option try a different antena with a bit more directivity.

Good luck and have fun with it!
OP | Post 8 made on Tuesday December 6, 2011 at 15:58
purtypitcher
Lurking Member
Joined:
Posts:
December 2011
5
Just got off the phone with Panasonic, they never have responded to my email. At first when I told the phone rep I was getting 75-80-85% signal strength on the Panasonic's meter she thought those were plenty strong. But then I repeated my main question which is why won't it work then, when the old TV/converter box does work?

After putting me on hold to find out (sigh), she came back and said the problem is that I need an even stronger signal because my TV has a QAM tuner. New term for me, sorry, I have been out of TV mode for a long time and didn't know things were getting this complicated.

So, some more internet research shows me that QAM tuners need "cleaner" signals then just ATSC tuners. So, probably my Digital Stream converter box that I have been using has an ATSC tuner and only needs to convert to low rez analog anyway for the old analog TV, so that's why I'm picking everything up with that one because it doesn't need as strong a signal. Does that sound right?

I'm still going to try my indoor antenna on the neighbor's Vizio TV, and see what happens, but it looks like I may have to get a much stronger antenna for OTA from 3.3 miles away from the CBS affiliate tower!

So, based on my earlier post showing all the stations, distances, azimuth differences, etc., what might be some good antennas to look for? I can do outdoor if I have to, but would prefer attic or really good amped indoor, or something with as little complication as possible. All of the local stations are UHF. Thanks.
Post 9 made on Tuesday December 6, 2011 at 19:59
Nueatit
Long Time Member
Joined:
Posts:
August 2008
148
It appears Panasonic are skirting the issue, digital does not need a stronger signal than ntsc, old rf chns, since digital needs less signal to noise ratio, etc.

QAM (quadrature amplitude modulation) is a method of combining two amplitude-modulated (AM) signals into a single channel, thereby doubling the effective bandwidth. QAM is used with pulse amplitude modulation (PAM) in digital systems.

ATSC uses 8vsb modulation.

All tvs have both types of demodulation capacity in a tuner, since they have to work for cable (QAM) and OTA ATSC. MOST set top boxes also do both, mine does.

I have in attic mouted uhf yagi, 50 feet co-ax, then a pre-amp in basement, split 4 ways. (amp in basement easier to get at etc.) Furthest distance to NBC is 90 miles (Buffalo) shooting thru Toronto CN Tower 10 miles away inline with Buffalo stations.

Suggestion, an 8 bay bowtie pointing 143 degrees, back of antenna more or less to local stations and a pre-amp of about 18 dB should be all you need.

Look for low cost antenna and pre-amp, all should work. Mind you it can still be a hit and miss, fine tuning always required.

Update: Suggest pointing antenna to about 120 degrees first, local channels will come in off the side or a little of the back, the antenna gain will be reduced in this direction by at least 15 dB or more, the pre-amp will cover this loss and since locals are lower in rf signal strength, the pre-amp should not over load.

If thhe 8 Bay is too large, you can always try with a 4 bay antenna at first. Why oversize if not needed. However, winter rf reception (no leaves on trees will be different than summer) also the roof material with snow/rain will attenuate the signal up to 10 - 15 dB and will vary.

Overall best is outside antenna. I will go this route myself next spring.

Last edited by Nueatit on December 7, 2011 09:34.
OP | Post 10 made on Wednesday December 7, 2011 at 13:30
purtypitcher
Lurking Member
Joined:
Posts:
December 2011
5
I'll report back in a few days after I have a chance to try some antenna options. In the meantime, just to recheck, I hooked up my existing Philips non-amped indoor back up to the Digital Stream converter / analog TV setup, put the antenna on the hardwood floor of my ground level TV room, and pulled in all six local channels perfectly, including the station that is 46.1 miles away, without having to move the antenna at all.
Post 11 made on Wednesday December 7, 2011 at 16:44
isotack
Long Time Member
Joined:
Posts:
March 2010
17
On December 7, 2011 at 13:30, purtypitcher said...
I'll report back in a few days after I have a chance to try some antenna options. In the meantime, just to recheck, I hooked up my existing Philips non-amped indoor back up to the Digital Stream converter / analog TV setup, put the antenna on the hardwood floor of my ground level TV room, and pulled in all six local channels perfectly, including the station that is 46.1 miles away, without having to move the antenna at all.

Why don't you just put an amplifier on it? Or go get an amplified version of that antenna from Walmart like I have.
Post 12 made on Thursday December 8, 2011 at 12:10
Nueatit
Long Time Member
Joined:
Posts:
August 2008
148
Based on what you mentioned and tested, looks like the Panasonic tv tuner has a defect, suggest to exchange it for another or another brand. It does not sound right.

However, an attic antenna will always perform better than rabbit types and may even cover signal drops due to weather.
Post 13 made on Sunday December 11, 2011 at 12:40
BillFromGI
Long Time Member
Joined:
Posts:
March 2009
179
I spent a little time reading up on HDTV tuner sensitivity on other forums and it appears that Panasonic does not rate high in this area. Suggest Samsung/LG/Zenith with Sony a close 2nd if tuner sensitivity needs to rate high for you...

For what its worth, I own a 4 year old Dynex. Never had tuner issues with it.
OP | Post 14 made on Wednesday December 14, 2011 at 14:47
purtypitcher
Lurking Member
Joined:
Posts:
December 2011
5
Follow up- I tried a couple of different indoor "flat" antennas, one is an RCA with an in-line amp, and the other is something called a Leaf antenna. They are both about 8 x 10 inches, but the Leaf is super thin, almost like a sheet of paper encased in a plastic laminate. I also spent more time with my original Philips, trying new positions, closer to outside walls, etc.

Both the RCA and the LEAF are able to get all the local stations easily, even the one that is 46 miles away. The Leaf basically matches the RCA in signal strength, but does it without the in-line amp. I was also able to get my Philips to get all the stations when I used the in-line amp that came with the RCA.

So, I think the tuner in the Panasonic is not as sensitive as the set top converter feeding my old analog TV, but both the new antennas work well enough, and I was getting higher signal strength readings from both of them than from the Philips. I'm going to keep the Leaf and take back the RCA.

Thanks a lot for all the comments and advice. Now, I've discovered another problem with the TV (not reception related), a well documented issue called "floating blacks". When high contrast scenes change, the TV makes abrupt, but delayed, changes in black level to adjust for different contrasts in the scenes. It's pretty distracting, but there is supposed to be a fix from Panasonic. So, one more issue to hopefully solve before my return period expires.
Post 15 made on Friday December 30, 2011 at 11:21
Ernie Gilman
Yes, That Ernie!
Joined:
Posts:
December 2001
29,818
I hope you returned that TV!

The floating blacks are reason enough.

The Panasonic lady saying your problem is because the TV has a QAM tuner is very much like saying your car FM radio won't work on FM because it has an AM tuner in it. The broadcasts you're trying to receiver are all ATSC so only the ATSC portion matters. If she's saying Panasonic can't make a tuner that does both, then her excuse makes sense.
A good answer is easier with a clear question giving the make and model of everything.
"The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
Page 1 of 2


Jump to


Protected Feature Before you can reply to a message...
You must first register for a Remote Central user account - it's fast and free! Or, if you already have an account, please login now.

Please read the following: Unsolicited commercial advertisements are absolutely not permitted on this forum. Other private buy & sell messages should be posted to our Marketplace. For information on how to advertise your service or product click here. Remote Central reserves the right to remove or modify any post that is deemed inappropriate.

Hosting Services by ipHouse