AVS Forum banner
Status
Not open for further replies.
1 - 20 of 36 Posts

·
Registered
Joined
·
33,593 Posts
Discussion Starter · #1 ·
I got off the phone a little while ago with the chief tech at Panny regarding picture drop outs and momentary total picture blackouts. My signal stength on Sat B is in the area of 85 with the lowest transponder at 78. I've had the RCA DTC100 for nearly a year and have never experienced anything like this. Nothing has changed in my setup and simply replacing the Panny with the RCA restores uninterrupted picture quality. I get NO dropouts with hi def from OTA signals through the Panny.


Now here's the issue. According to the tech, the new genereation Panasonic is much less tolerant to signal variations than the RCA. He feels that a MINIMUM signal strength of 85 is required on ALL transponders of Sat B to get a picture free of dropouts. Additionally he felt that too high a signal strength is also causing problems in some setups. I indicated that since Sat B is a tougher signal to receive in almost all parts of the country and will usually be a lower signal strength than Sat A, there will be many many problems with this receiver in areas that have never had problems with the RCA. He acknowledged this and felt that this was the price you paid for the better picture quality of the Panny.


To further confuse the issue, when I got off the phone I hooked up my high def cable feed to the Panny to check out how HBO HD comes in via my cable feed. The signal strength on this HBO HD feed is actually significantly LOWER than my HBO HD feed via satellite (as measured by the RCA)!!! The result? PERFECT PICTURE QUALITY WITH NO DROPOUTS!!! I proposed this possible scenerio to the tech prior to my actually conducting this test, and asked if I did get this result what did he then think about low signal strength vs dropouts then? He said if that's what happens then there is some problem with DirecTV's transmission. If so, why doesn't it bother the RCA???


I am very confused and becoming more and more skeptical. Is this a bad sample of this unit or is the Panny design lacking?

 

·
Registered
Joined
·
540 Posts
Ken... seems you and I both spoke to "stan"... I'm very concerned as well... but the strange thing is, I've had almost no dropouts tonight (except for a five minute period one hour into "any given sunday". My signal is 78% on both 23 and 25--the two hbo-hd transponders.


Now I'm really confused (although not disapointed with tonights results). Still, I'm demo-ing the sony later in the week.


By the way... how was your reception tonight?
 

·
Registered
Joined
·
33,593 Posts
Discussion Starter · #4 ·
lhamp,

Very interesting. My strengths are exactly the same as your but I guess that's not surprising since we live close by. Yup, I spoke with Stan. I'm just not sure I buy into this stuff. I told him I thought that if this was true, than this was a very poor design. To have such a narrow tolerance (both high and low) for as many installations as would be expected in as many parts of the country that are covered by DTV, is ridiculous. I would think a fairly small percentage of Panny owners are going to get glitch free reception. I asked him if he thought my unit was defective and he seemed to feel it wasn't. NOT a good sign. Ofcourse he also indicated how expensive repairs and swap-outs are for the company. I can appreciate that, but what is the consumer supposed to do?
 

·
Registered
Joined
·
33,593 Posts
Discussion Starter · #5 ·
Forgot to mention about tonight. Yes, there were fewer dropouts tonight but still more than I've ever had with the RCA. I'm hoping to pick up the Sony tomorrow.
 

·
Registered
Joined
·
540 Posts
thanks ken... I look foward to hearing what you think about the sony since I'll be picking one up later in the week.


509 still looking good tonight. In an unrelated topic, the sound is superb. Great 5.1 with no drop-outs.
 

·
Registered
Joined
·
1,797 Posts
To further confuse the issue, when I got off the phone I hooked up my high def cable feed to the Panny to check out how HBO HD comes in via my cable feed. The signal strength on this HBO HD feed is actually significantly LOWER than my HBO HD feed via satellite (as measured by the RCA)!!! The result? PERFECT PICTURE QUALITY WITH NO DROPOUTS!!!


Remember that most (if not all) cable systems are sending HD via 8VSB, which would equate to an OTA reception profile. Could be wrong about this, but I'm pretty sure DirecTV is not using 8VSB to transmit HD.


------------------
BOYCOTT DVI/HDCP & JVC!
 

·
Registered
Joined
·
33,593 Posts
Discussion Starter · #8 ·
You are correct dkeller, satellite does not use 8VSB. My point however, was that this does NOT appear to be an issue related to signal strength in the manner described by Pansonic. Whatever the reason, the Panny has no problem with a lower signal strength 8VSB signal as opposed to a HIGHER signal strength reading from HD satellite. I have no idea what's going on, but I am very skeptical that this is an issue with DirecTV.


When I mentioned this possible scenario to the tech (receiving the weaker HD cable signal with no problem as opposed to glitches with a higher strength HD sat signal) he said if that happens I should talk to DirecTV. If this is the case, why have I had no problems with the RCA for nearly a year in the same setup? This is NOT progress. This should NOT be considered a new "feature" of a next generation STB. If it is, I'd hate to see what the 3rd generation box will be like. As these products improve they should be LESS demanding of signal strengths and variations, not more.
 

·
Registered
Joined
·
1,797 Posts
I don't disagree that this is a design problem with the panny - I can get a maximum of 55 signal strength on sat B with my RCA, and I have no problems with dropouts on the DTC-100 (or, for that matter, on a Sony A55 for the NASA channel).


On the other hand, since the two modulation schemes are different, I'm not sure you can compare the performance of 8VSB with DirecTV's signal - the DTC-100 would certainly not perform well with an OTA signal strength of 55!


------------------
BOYCOTT DVI/HDCP & JVC!
 

·
Registered
Joined
·
63 Posts
I am using the Panny TU-HDS20, and I have never experienced a video or audio dropout. I've had it installed since Jan. 5 and my signal strength on Sat. B for transponder 23 is 59% and for transponder 25 is 38%. I really only consistently watch the Sopranos on 509, but on this past Sunday it was perfect, I never saw or heard a problem. If Panasonic is trying to blame signal strength, my experience throws a wrench into their theory. I would try to get another TU-HDS20 to test against.


Todd
 

·
Registered
Joined
·
147 Posts
I second ToddMK's comments. I haven't had any problems whatsoever with the hbo hi def channels. No problems with ota reception either. I don't buy statements that there are design deficiencies in this device. The info that's coming from the panasonic support people doesn't make sense. I don't think their support staff have the technical background to deal with some of these issues, so they say whatever comes into their heads to get you off the phone.


Also, the direct TV high definition has to be using 8vsb. How else could they possibly provide a digital high definition broadcast? Do they have some sort of proprietary modulation scheme that they are using. No way. The HBO feed is high definition via 8vsb, and DirecTV passes it on through their system to the users in that format.
 

·
Registered
Joined
·
5,658 Posts
Quote:
Also, the direct TV high definition has to be using 8vsb. How else could they possibly provide a digital high definition broadcast? Do they have some sort of proprietary modulation scheme that they are using. No way. The HBO feed is high definition via 8vsb, and DirecTV passes it on through their system to the users in that format.
8VSB doesn't not mean HD....there are lots of ways to modulate the signal and still transmit a HD signal (i.e., COFDM, QAM).


Using your rationale we could conclude that all of DirecTv signals are 8VSB or the HD ones are 8VSB and the SD signals are NTSC. The truth is that DirecTv system has it's own unique modulation system, and it's not 8VSB, nor NTSC. The HD signals are modulated in the same manner as the SD signals but are allocated more bandwidth.




------------------

Geof
 

·
Registered
Joined
·
147 Posts
I don't buy that explanation. HBO is simply supplying a mpeg-2 digital data stream that's in turn supplied to us via DirecTV. That data stream enters our system via the stb which I believe uses a single chip (8vsb Broadcomm, Motorola, whatever) programmed to process that datastream, modulate it and upconvert it to analog. If what you are saying is true then inside the stb there would have to be a second dedicated receiver using a proprietary modulation scheme to do the conversion from digital to analog. Why would DirecTV complicate their lives with this type of hardware configuration?
 

·
Registered
Joined
·
136 Posts
Just to chime in here, I have not experienced any drop-outs or interuptions on my panny ( since 2-5-01 ). Signal strength is at 82 to 88. It may be slow and loud but it works like a charm. ( Oh know! I just jinxed myself now!)

Gebstr83
 

·
Registered
Joined
·
33,593 Posts
Discussion Starter · #15 ·
I agree with those of you that have suggested my box is defective. That's what I was implying with the HEAD tech at Panasonic. He felt the odds were very low that it was a defective unit.


Dkeller,

You may well be right about not being able to compare signal stengths with two totally different modulation schemes. I just don't know for sure. I do know that if Panasonic were right about the signal requirements of this new box (and others have posted from their own experience that this is NOT the case), then this is a terrible design issue. The tech insisted that the chips that do the processing are all the same whether or not it sees a DTV HD feed or an 8VSB feed. This was his rational for saying that if I got an uninterrupted picture with HBO HD from cable (which I did) then that proves its a problem on DTVs end. Hmmmm.
 

·
Registered
Joined
·
1,797 Posts
"The tech insisted that the chips that do the processing are all the same whether or not it sees a DTV HD feed or an 8VSB feed."


If he was referring to the D/A conversion, I could understand that, but it ssounds like you've got a de-modulation problem, and those are definitely NOT the same chips - last I heard, Nxtwave wasn't producing any Ku band de-modulation chips!


------------------
BOYCOTT DVI/HDCP & JVC!
 

·
Registered
Joined
·
540 Posts
New observations:

Sunday night: the Sopranos was almost unwatchable... dropouts ever couple of minutes.

Monday night: "Any given sunday"... very good reception. Almost no dropouts.

Tues night: "I dreamed of Africa"... very good reception. Just a couple of glitches here and there.

Tues 11 PM: The Sopranos... again... almost unwatchable... same exact problems.


All of which leads me to believe directtv/hbo has at least something to do with this.


Thoughts?
 

·
Registered
Joined
·
33,593 Posts
Discussion Starter · #19 ·
lhamp,

I just got the Sony today. Major major improvement over the Panny. NO dropouts, picture quality as good as the Panny if not better, and an incredibly quick menu/guide system. I've been playing with it now for about 6 hours and have not had a single problem or issue, which makes it unique for the 4 STBs I've used. Thus far it is unquestionably a keeper and the Panny is going home.
 

·
Registered
Joined
·
17 Posts
Quote:
Originally posted by Ken Ross:
I got off the phone a little while ago with the chief tech at Panny regarding picture drop outs and momentary total picture blackouts. My signal stength on Sat B is in the area of 85 with the lowest transponder at 78. I've had the RCA DTC100 for nearly a year and have never experienced anything like this. Nothing has changed in my setup and simply replacing the Panny with the RCA restores uninterrupted picture quality. I get NO dropouts with hi def from OTA signals through the Panny.


Now here's the issue. According to the tech, the new genereation Panasonic is much less tolerant to signal variations than the RCA. He feels that a MINIMUM signal strength of 85 is required on ALL transponders of Sat B to get a picture free of dropouts. Additionally he felt that too high a signal strength is also causing problems in some setups. I indicated that since Sat B is a tougher signal to receive in almost all parts of the country and will usually be a lower signal strength than Sat A, there will be many many problems with this receiver in areas that have never had problems with the RCA. He acknowledged this and felt that this was the price you paid for the better picture quality of the Panny.


To further confuse the issue, when I got off the phone I hooked up my high def cable feed to the Panny to check out how HBO HD comes in via my cable feed. The signal strength on this HBO HD feed is actually significantly LOWER than my HBO HD feed via satellite (as measured by the RCA)!!! The result? PERFECT PICTURE QUALITY WITH NO DROPOUTS!!! I proposed this possible scenerio to the tech prior to my actually conducting this test, and asked if I did get this result what did he then think about low signal strength vs dropouts then? He said if that's what happens then there is some problem with DirecTV's transmission. If so, why doesn't it bother the RCA???


I am very confused and becoming more and more skeptical. Is this a bad sample of this unit or is the Panny design lacking?
Dear Mr. Ross,


Our manual and engineers have told us that 85% is what we need for hi-def on Sat B. I won't deny some people might be getting it with lower signal strength, but when all else fails, I tend to insist on complying with specs in troubleshooting. The issue of signal strength being too strong is not on DTV or the dish, but with HDTV through antenna. In some cases, if the antenna has too much gain, it can end up looking right through/past the signal you intend to receive. If you are at the signal, but there is too much gain, that can also cause the signal to wash out. I am not an engineer and do not know the full details of this, but have heard this from engineering and some customers who have verified this with local installers.

Cable imay be weaker signal than antenna/dish in a lot of cases, but it is also a direct link and not a transmission through air/space. Unlike signals that have to have enough power to travel a certain distance, cable is often amplified, repeated or boosted within much shorter distances. It also uses a different format to transmit data. The receiver is equipped to handle that format. Since the format is different, it's video and audio may be sent and decoded differently, and some of the issue that can occur over dish and antenna may not be as likely to happen over cable.

Between the fact that I have not yet heard from engineering on this dropout issue, and the fact that I have seen on this and other forums discussion about dropout from other rcvr companies, I am not yet sold on the idea that this is a defect with the rcvr's. I hope that people realize that we are not intentionally giving you a runaround or trying to get rid of you. I have spent enough time on the phone with you and others on this issue, and now replying here that I would think no one would believe I was just trying to get rid of you. Your satisfaction with your product is important to our company and that we put %100 into finding resolutions or offering fsc/xchg. At this time information is limited to me, and as such I am doing the best with little material to work with. If I don't exchange a lot of units right now, it is simply because exchanging units without concretely knowing if it is a signal or rcvr problem causes a shortage of units for problems that are more easily identifiable and that we know we can fix. If I do an exchange it the problem is signal related, chances are, I won't resolve your issue. That doesn't get us any closer to customer satisfaction either. I am sorry that you decided to move on to another brand. I wish you well and hope that as HDTV developes more, you'll find a reason to come back to us.


Sincerely,

Stan
 
1 - 20 of 36 Posts
Status
Not open for further replies.
Top