: Rogers STB issues (Ground Loop)
2008-01-21, 01:51 PM
Ok, I decided after noticing that when watching 720p programing that the "interferance lines" didn't seem to be as apparant as when watching 1080i. As I had mentioned previously both 1080i and 720p broadcasts the horizontal lines are less noticable after a better surge protector, and grounding my cable. However, my Xbox 360 still had the horizontal lines appearing (especially in dark games). I had my Xbox 360 settings at (widescreen - 1080i) setting. I just changed them to widescreen - 720p) The linea are gone. Why would that be? My LCD is a The new LG 42LB4D LCD HDTV with a 120Hz screen refresh rate. Since it's 120Hz, could what I have been seeing be a refresh issue? That is what it always looked like to me. I just hooked up my computer via the RGB input, and the picture is AMAZING. No horizontal lines with settings at 1360x768, so that is all good. I would love to finally get a solution/explanation to this. I seem to be getting closer:confused:
This sounds like an ingress signal beating with the vertical sync pulses on the component video interface. 1080i and 720p use different vertical refresh rates although there are actually 60 vertical blanking intervals per second for both. That is why I asked in post #2 if it does that when you use the HDMI interface (digital all the way).
2008-01-22, 12:56 PM
So since I don't have HDMI cables (I guess its DVI to HDMI for the Rogers STB) Should I go into the STB wizzard and remove 1080i as a format option, so 720p is highest quaility format? I'm still hoping that this can be actually resolved instead of loosing 1080i. Quailty wise I can't really notice a difference between 720p, and 1080i except 1080i seems to be a bit sharper.
You don't need to remove 1080i as a test you can simply switch the "set picture format" to Upconvert2, which changes 1080i to 720P. If you click info when you're in there, it may even be explained.
2008-01-22, 02:57 PM
Thanks for all the advice. I will set the picture format to Upconvert2 instead of passthrough in the STB setup menu to see if this removes the horizontal lines.
Is this a known issue? I have looked in these forums a lot, and I have not come across someone else that has this problem. Perhaps, it's common, but some people haven't noticed it the way have. Though I doubt that.
Using various workarounds, people have been able to minimize the ground loop issue.
- using various types of connections - HDMI instead of CV
- using a grounded power bar and running the cable through it
- using various formats
However, the root cause of the issue is really what people should be fixing, not looking for band-aids.
Either the cable is still not yet properly grounded, or perhaps you have some signal ingress to some of the connections. Perhaps moving the cables around will help, or trying different cables, separate the A/C cords from the signal cables whenever possible, etc.
2008-01-22, 03:57 PM
Thanks again. I have tried separating all my A/V cables from power cables. Well as best I could. It did seem to help a little. As you know there are so many when you have a STB, multiple Game Consoles, A/V receiver, and computer. There are a ton of cables to deal with.
I am quite sure my Rogers cable is grounded, but perhaps there is an all around house grounding issue. It is a very old house, but I was told recently, that my breaker box was well grounded, and up to code. All my A/V equipment is on its own circuit too.
You guys have all been very helpful, and I appreciate all the suggestions/support. I will continue to try new fixes, and let you know when I have a solution.
2008-01-22, 07:30 PM
I tried changing my video set-up on my rogers stb from pass-through to upconvert2. Yes, it took all HD channels originally 1080i and converted them to 720p. And yes, the lines were gone. However, the downside (well there are two) 1. all SD channels now are broadcasted native 480p instead of 480i. For a sd channel this brings down the quality a lot. (trying to force a SD singnal into HD doesn't work so well) 2.The other downside is the picture quality seems not as good as before. After I changed it, I can see that I would probably have to re-adjust all my video settings to compensate, however, I can't have 480p replace 480i for my SD channels the quality sucks. Funny too, when I hit the zoom button for the SD channels it goes to 1080i stretch. Would the solution be to remove 480p all together from the STB? I know regardless this is all a stop gap aproach to addressing the real issues, however, Since no one can seem to compterly solve this problem on my end, I'm running out of options...
The upconvert 2 was just as a test. If you want, you should now simply enable 480i standard and 720P in the setup wizard.
2008-01-22, 09:26 PM
Ya that's what I thought. Cool. I had initially enabled 480i standard, as well as 480p standard when I first set up the STB, So I will remove both 480p, and 1080i, Thus making 720p the highest standard attainable, and not allowing for 480p to be an option at all (not that I need that anyway). I have been going back and fourth checking picture quality on HD to see if I can see any difference from 720p to 1080i. I can't really. I will make the changes, and then try to continue to solve the problem once and for all, so I can enable 1080i again without the interferance. I may go with DVI to HDMI, which would also allow me to have it all. For now everything works fine. Thanks again! :)
Just as an FYI, the LG may not accept 480i via HDMI.
2008-01-23, 03:04 PM
Exactly. I read your thread when I first got the HDTV. I may borrow a cable and try it first, before I buy.
Borrowing a cable to test 1080i over HDMI would also help confirm or deny an ingress problem over CV. Note: It's also possible (but unlikely) that the ingress source is inside the TV itself.