Why do have video hum bars on my DishNet Receiver via HDMI? Help me.

Guys,

I have the latest DishNetwork High Definition DVR set-top box. Whenever I hook an HDMI cable up to it, I get a wicked case of horizontal lines, scrolling vertically, over any video image from any source. The obvious explanation is ground loop, right?

Except I don't think that's the issue. My DishNet guy tells me that the latest hardware does not require a grounding block and is somehow grounded through the set-top box. Meaning that there is no ground reference issue, since the dish is grounded the same place as everything else.

My question to you guys is this: Are there any known issues with "ground loop like" interference coming from these new MPEG4 DishNet boxes?

I'm pulling my hair out trying to get these video hum bars to go away. Disconnecting the HDMI cable from the settop box will do the trick, but that's an annoying thing to have to do, plus it doesn't help with satellite viewing, obviously.

Any help is much appreciated.

Oh, and one more thing. Even if I unhook all of the incoming coax from the settop box, so there is no signal coming down from the dish on the roof, the contact of the HDMI cable to the HDMI-out on the settop box remains an instant humbar catalyst. By the way, I get the same effect on two separate HDMI cables, not just one.

Holy crap this is aggrivating.

Dude, I have no idea what to believe at this point. I'm not an electrician. Hell, I don't even profess to having any common sense regarding electricity.

He tells me that his company doesn't ground any of the newer dishes in homes with 3 pronged outlets. I shouldn't be put in a position where I have to educate the guy who is supposed to be an expert on installing the damned dish, but that's the situation I am in.

But forget about the grounding situation for a moment. I only brought it up because I knew someone was going to suggest ground loop as a possible cause. It's not a ground loop, as far as I can tell -- at least not in the traditional sense -- since the video hum remains present even when the coax input is disconnected from the box entirely.

So allow me to restate my question: Does anyone know if these new DishNet DVR settop boxes have a problem with video hum or any other suggestions for what might be causing this?

P.S.

In the event of a direct lightning strike, everyone tells me I'm screwed anyway. My understanding was that the ground was to prevent the build up of static electricity to prevent the dish from becoming a lightning rod. But I really don't understand any of this. Guys, sometimes I just plain get tired of having to understand EVERY freakin' aspect of everyone else's job. People should know how to do their own jobs.

I just finished building my home theater. I hired the job out to a general contractor (first mistake) and I've spent the last 5 agonizing months having to second guess this guy and his merry band of misfits on nearly every decision they made. I had to become an expert on HVAC, basic carpentry, etc. and I'm just exhausted. And now I've got to second guess the DishNet people? Someone needs to lend me a tire iron. The next fool who shows up at my house without a solid understanding of how to do their own job is going to get it delivered to them royal style.

Did some more trouble shooting. Both of the settop boxes in my house (one MPEG4 HD DVR, one mpeg4 HD without DVR) are generating hum.

The problem is not a ground loop.

The problem is not the cables or their tendency to act as an antenna, since I can use the same HDMI cable on a different gadget (DVD player) and I do not get hum.

I think the problem is that both of these boxes are generating some crazy loop-like interferance of their own and sending it down the signal path. Since both boxes are doing it, I'm led to believe that it may be a systemic problem with DishNet's newest MPEG4 boxes.

But if that's the case, I would expect someone else to have seen it.

Try this: If you have the DVD for King Kong, go to the very beginning of the chapter where all of those nasty bugs attack them in the cave. Pause the picture at the moment that the writer first begins to see the bugs emerging from the darkness. It's like 5 or 6 seconds into the chapter.

This is the easiest scene for me to spot the interference on. For the rest of you with these MPEG4 HD-DVR combo boxes, are you seeing this interefence too?

By the way, the receiver that is giving me such a headache is the VIP622.

I guess the lack of a response indicates that no one has noticed video hum on the VIP622?

Well, making the installer stay until the unit was functioning properly would have been one amazing feat, considering that my projector wasn't even hooked up until 4 days later. That, my friend, was the product of contractors who couldn't finish anything even remotely on schedule.

I do have the cell phone number of the installer, and he said to give him a ring directly if I want help figuring out this particular problem (long story). So I think I'll give him a buzz and see if he'll drop by and try out a new settop box to see if that fixes the problem.

I think there might be some wonky wiring inside my VIP622. The hum bars show up the second that the HDMI cable touches the output on the back of the box, and it also shows up if I touch the HDMI to the ethernet jack, a strange fact that I discovered by accident. I'm thinking loose wire?

By the way, are HDMI cables prone to picking up electrical interference from nearby AC lines?

Thanks John.

I had read that thread previously, but I read it once more hoping to find some enlightenment. In fact, that thread was the reason that I asked if HDMI was prone to AC line interference -- because I do have yellow electric line running within 6 inches of my HDMI cable over a small stretch.

But I don't think that AC line intereference really explains my issue (whether or not HDMI is subject to it), since I can use the exact same HDMI cable on my DVD players and the "loop" is vastly reduced.

Unfortunately, my projector is not in the same room with the rest of the gear, so I cannot easily plug it into the same power strip.


I bought two large ferrite chokes and tried to use those, but it didn't seem to make much of a difference. I tried to wrap the HDMI cable around the core, but I couldn't get more than one loop because the choke was fairly small and my HDMI cable is very thick. If I loop that thing too tightly, I'm afraid I'll break it. Do they make really big Ferrite chokes?



Can I use a ground breaking transformer for HD satellite? I thought those only worked with cable? If you know of a good one that will work with sat. please let me know.

But I don't have much hope that it's a grounding issue with the coax line, since the hum bars are still there even when I disconnect all of the coax cable from the box.

The safety issue, however, is something I can appreciate. I guess I need to call this guy back up and insist on a grounding block. And since my main house ground is on the other side of the finished basement, my guess is that the grounding block is going to introduce a genuine ground loop. Sigh.