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So far, I've tested a few tapes containing shows I've recorded on my Govideo VCR and most, if not all, seem to be affected by this problem. The picture appears fine when viewed via the TV only, however, when viewed through L1 (my setting for the VCR) the behavior is readily apparent and is very noticeable in regard to the fluctuation of skin tones. Oddly enough, last evening while suffering through this irritation, the fluctuations evaporated after about 20 minutes or so and the coloring then appeared stable throughout the duration of the recording???


Additionally, after performing a search on this topic, it seems I'm not the only one to experience this particular issue. From my reading, it does indeed appear to be somewhat related to the specific VCR attached and how the unit interacts with the Panny's built in TBC for enhancement of vhs tapes. It also seems to be present regardless of whether one uses composite or S-Video cables since the Panny's TBC is in work for both. If anyone has an alternative solution for this, other than purchasing another vcr unit, I'd love to hear it as I certainly am not looking to discard my handy GoVideo macrokiller simply to work around this issue.
 

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I've seen this before. Its technical name is differential phase error, and its marked by skin tones fluctuating from just too pink to just too green every half second or so. Under 1% or so is acceptable, and equipment normally does not behave this way on its own (see below). If you can see it, the DFE is likely 5% or more. Since NTSC hue is determined by phase shift from a reference burst, something that modulates this will present itself as shifting color hue. You would need a vectorscope to really see this, but while using one even very low values of DFE can be seen.


The few times I've seen it have been in consumer gear and was due to inter-chassis interference. IOW, when two pieces of gear are within a few inches of each other, sometimes when one is on one channel and the other on another, the sync pulses beat together causing this.


You may see it come and go, and may not realize that it does this because one or the other piece of gear is turned off or on, or a channel change occurs, causing the beat frequency to change and making things either more or less noticeable.


The permanent cure is to move the two offending pieces of equipment farther away from each other, which normally fixes it every time. Try moving one unit one shelf further away, and report back, hopefully with a success story.
 

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I don't know that I saw this potential solution posted before. but maybe I'm forgetting. Either way, thanks Tom!
 

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TomCat,


That is a very interesting explanation!


I just replaced a JVC S-VHS machine with a Panasonic E80 DVD Recorder because of color problems like those discribed. Although my color problems were only on the top 20% of the screen. I wonder if moving components around would have solved that?


Oh well, life is alot better with the E80 anyway. :)
 

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I am having similar problems on my E80, but NOT with a VCR. I am trying to record 480i downsampled HDTV off my STB via the S-video port. I get these color fluctuations on ONE station only. And ALWAYS on that station. If I connect the tuner directly to the back of the TV, it is fine...


I tried out TomCat's suggestion, but there is no spot within reach of my 6ft S-video cable that seemed to matter. Still see the fluctuations no matter where I place the tuner.


Is it possible that other components near the E80 are causing the problem? (I'd rather not tear down the whole cabinet if I don't have to... )


If it's the TBC causing all the problems, is this something that can be turned off?
 

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potus,

Quote:
If it's the TBC causing all the problems, is this something that can be turned off?
I suspected I had digital artifact problems relating to the TBC in my E80H as the artifacts were induced into the "MONITORED" signal when I wasn't even recording!


Unfortunately there is no way to turn the TBC off and I returned my E80H to Sears for a refund. It was really hard as they price matched a $533 price.:mad:


After reading more and more threads, it seems Panasonic has a continuing reliability or design problem with the E80H judging from these fluctuation complaints and hard drive problem complaints.


Panasonic is my favorite brand as of now, but it seems they always have severe problems on new technologies. I suffered this with my A320 DVD Player that had a design flaw that caused the first chapter on the 2nd layer of a disc to be skipped. They gave me no help in this issue so it was exchanged for a Pioneer DV-414. My buddies CD Player was one in the first few years of CD's life and it had design defects where the whole tracking mechanism had to be replaced. It does seem once Panasonic gets their bugs worked out, they offer very high performance for the dollar. However, I was severely disappointed by the E80H's performance and many others makers for that matter, but I'm trying again with a Pioneer DVR-510H. Picking it up tonight. Hopefully I'll have good luck with this Pioneer. The luck with the Pioneer DVR-310 wasn't good at all.


Have a good one.
 

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Quote:
Originally posted by potus
I am having similar problems on my E80, but NOT with a VCR. I am trying to record 480i downsampled HDTV off my STB via the S-video port. I get these color fluctuations on ONE station only...


I tried out TomCat's suggestion, but there is no spot within reach of my 6ft S-video cable that seemed to matter...
I wish I had an answer, but my earlier post refered only to problems with NTSC analog, which differential phase error is a possible artifact of. Once we get into the realm of digital, none of that likely applies. My best guess would be that there is something funky about the downsampling that could be causing this, and it could even result in DFE once the signal is back in the analog realm and being input to your DVDR. I would think this more likely than inter-chassis interference in this case.


Every HD station uses equipment that is a little different than the next, and different algorithms exist for them to do essentially the same job, which might be at the root of why this is only on one station. The particular way they do things coupled with the particular way the E80 does things (or possibly the way the equipment doing the downsampling does things) is probably why you are getting that particular result. I know that's a little more vague than helpful, but likely still the way things are.


Regarding my suggestion for true sufferers of inter-chassis interference, it is unlikely that you need to move pesky units much further apart than a foot or two. It usually happens when two components are closely stacked or on adjacent shelves. Good luck potus.
 

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Thanks for the info...


My case is a little confusing. Although my situation IS in the "digital realm", when my DTV tuner downsamples to 480i, it MUST be converting to analog NTSC. It's meant to drive standard NTSC displays. So we are back in the analog domain. (At least for signal between tuner and E80)


One might then expect that ALL 480i coming from my tuner would exhibit this problem on the E80. In fact, MOST of it is fine. Just the one station has these fluctuations. Other NTSC sources (composite out from my miniDV cam, and from my Sony VCR) are ALSO fine. So there must be something just a little "funny" about this particular NTSC signal that is throwing the E80 for a spin... It sounds like the problem is a sensitivity of the E80 to _some_ NTSC signals....


So the next question is: is there any way I could "clean-up", or "normalize" the analog signal before feeding it to the E80? I tried one of those old "Video Stabilizers" (Macrovision removers...) but it didn't seem to make any difference. I thought about running the signal through my VCR, but I have a feeling the video outs would just be a direct pass-through...


Any ideas?
 

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Quote:
Originally posted by TomCat
I've seen this before. Its technical name is differential phase error, and its marked by skin tones fluctuating from just too pink to just too green every half second or so.
Maybe you need to get a job at directv, I've had this problem for a long time with my locals only. The faces aren't green but they are 'in and out'. Sounds like you could fix it right up for them :)
 

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Quote:
Maybe you need to get a job at directv, I've had this problem for a long time with my locals only. The faces aren't green but they are 'in and out'. Sounds like you could fix it right up for them
Fortunately my locals on DirecTV look as good as the HBO's.:)


Have a good one.
 

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Quote:
Originally posted by newsposter
Maybe you need to get a job at directv, I've had this problem for a long time with my locals only. The faces aren't green but they are 'in and out'. Sounds like you could fix it right up for them :)
Thanks. If I lose my current position by spending too much time on the forums I might just be forced to do that. But my guess is that the engineers there are painfully aware of most if not all of their warts...its just takes capital and equipment to fix it sometimes.


When must-carry happened a lot of less than desirable out-moded equipment got pressed back into service. I think they're more willing to tolerate this on locals that affect only one market than they are on PPV or core programming. At least there is competition in the marketplace since Echostar couldn't buy DTV. Maybe with Rupert at the helm things will improve.
 
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