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I just had an HR20 and new dish installed by DirecTV. The HR20 is in our living room, where our old Sony SAT-HD300 used to be. We moved the Sony to the guesthouse in the backyard. Here's the problem: When the HR20 is on, the Sony suffers from pixelization and squiggly lines, but only on a handful of channels like KCBS, HBO 504, and a Showtime channel. Any the problem does not happen all the time, but most often at night. DirecTV tech is stumped. They sent a serviceman out last week; he replaced the LMB section of the dish, and we thought it solved the problem, but 5 minutes after he left, the problem came back. I have another service call set for this Friday, but who knows. Cabling seems good, signal strength in excellent. DirecTV asked that I install a digital signal booster (which I did), but no effect (it's gone now). Any advice would be welcome.
 

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63strat said:
I just had an HR20 and new dish installed by DirecTV. The HR20 is in our living room, where our old Sony SAT-HD300 used to be. We moved the Sony to the guesthouse in the backyard. Here's the problem: When the HR20 is on, the Sony suffers from pixelization and squiggly lines, but only on a handful of channels like KCBS, HBO 504, and a Showtime channel. Any the problem does not happen all the time, but most often at night. DirecTV tech is stumped. They sent a serviceman out last week; he replaced the LMB section of the dish, and we thought it solved the problem, but 5 minutes after he left, the problem came back. I have another service call set for this Friday, but who knows. Cabling seems good, signal strength in excellent. DirecTV asked that I install a digital signal booster (which I did), but no effect (it's gone now). Any advice would be welcome.
I am going to make a big guess here, but you may have grounding problems. It is highly likely that there is a differences in electrical potential between the 2 buildings and your cable and STBs are bridging in the LNB in the dish. You might have the tech take your old dish and install it on the guest house. It would be a lot easier than trying to get both structures to use the same common ground. This can also cause bigger problems like shorting your equipment out or worse, I think you might be violating code by doing this too. This is outside of my area, but I have been exposed to this kind of problem with networks.

Your installer should know better, connecting 2 building with copper, without a common ground is a no no.
 

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btmoore said:
I am going to make a big guess here, but you may have grounding problems. It is highly likely that there is a differences in electrical potential between the 2 buildings and your cable and STBs are bridging in the LNB in the dish. You might have the tech take your old dish and install it on the guest house. It would be a lot easier than trying to get both structures to use the same common ground. This can also cause bigger problems like shorting your equipment out or worse, I think you might be violating code by doing this too. This is outside of my area, but I have been exposed to this kind of problem with networks.

Your installer should know better, connecting 2 building with copper, without a common ground is a no no.
btmoore is quite correct, technically. There is something you can try. Make sure both dishes are actually grounded to a ground rod just below their mounting position (assuming neither dish is on the roof). For safety grounds, if both dishes are grounded (via a short, fat wire, to at least a 4' rod, again, assuming normal (not rocky) soil conditions), you may eliminate your ground loop problem.

The actual difference in potential (with short ground cable runs to actual ground rods) should not be much of a problem, EXCEPT for RF and lightning (which has a strong RF component). So, you might cure your ground loop problem (if you have one), BUT you have done nothing to protect yourself from lightning damage (and no, I don't mean direct hits....I mean induced voltages from nearby strikes).
 

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hasan said:
btmoore is quite correct, technically. There is something you can try. Make sure both dishes are actually grounded to a ground rod just below their mounting position (assuming neither dish is on the roof). For safety grounds, if both dishes are grounded (via a short, fat wire, to at least a 4' rod, again, assuming normal (not rocky) soil conditions), you may eliminate your ground loop problem.

The actual difference in potential (with short ground cable runs to actual ground rods) should not be much of a problem, EXCEPT for RF and lightning (which has a strong RF component). So, you might cure your ground loop problem (if you have one), BUT you have done nothing to protect yourself from lightning damage (and no, I don't mean direct hits....I mean induced voltages from nearby strikes).
I think he is using 1 dish to feed 2 structures, that could be causing bridging between the 2 buildings to balance the potential difference. If he moved to 2 dishes one on each structure, I bet the problem goes away regardless of the grounding situation. The alternative is to make sure both structures have a common ground (not easy) and a grounding block is installed on both structures and they are attached to the common ground.

BTW I believe that connecting the 2 structures with copper and improper grounding is also an electrical and fire hazard.
 

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Here is another way to think of this.

You have 2 structures, on a dry windy day both structures can build up a static load. When you attach a conductor between the 2 structures you have provided a way for the difference in potential to be balanced. One way around this is a common ground, this allows the potential to be balanced via the ground. If the structures have separate grounds you will have a difference in potential. Now if that connection between the structures is coax with equipment attached, they could have problems all the way up to being zapped. I ran into this about 20 years ago back @ Purdue when we had someone try to run Thick Net between 2 buildings and it kept shorting out the bridging equipment every few months. We fixed it by converting it to fiber (non conductive).
 

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Discussion Starter · #8 ·
Thanks -- I have a single dish for feeding both receivers. However, this is the same setup I had before, only with 2 Sony HD receivers. My setup now is actually the HR20 (living room), Sony HD200 (home office), and the Sony HD-300 guesthouse. No problems with the Sony HD200.

I will try to swap the receivers, too, but have a feeling this isn't the issue. Strange how, if it's a grounding issue, that it only happens on a handful of channel (of course, always the exact ones I wan to watch).
 

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btmoore said:
I think he is using 1 dish to feed 2 structures, that could be causing bridging between the 2 buildings to balance the potential difference. If he moved to 2 dishes one on each structure, I bet the problem goes away regardless of the grounding situation. The alternative is to make sure both structures have a common ground (not easy) and a grounding block is installed on both structures and they are attached to the common ground.

BTW I believe that connecting the 2 structures with copper and improper grounding is also an electrical and fire hazard.
Yep, it certainly is...a true safety hazard (unless everything is GFI'd...then it's ok.
 
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