speaking of ground blocks....re: line noise

[bigtiii]

Last DTV installer put a ground block in my lines and I was wondering if they produce enough line noise that I should worry about it.


I was thinking if it does raise the noise level in the lines I'd just remove the block, ground the chassis of the Zinwell and get the block of the loop.

What say ye experts?

[aim2pls]

personally ... I'm anti-grounding .. but some customers request it

[LameLefty]

I've had all three dishes that I've ever had (2 different dual-LNB units at different houses and my current AT-9) grounded and never had any issues. I also never had some of those really weird signaling issues that plagued the HR20 for the first 3 - 4 months. Coincidence? Who knows? But the installation manuals always said ground it when I did it myself and I've insisted that installers do it too since then.

[bigtiii]

personally ... I'm anti-grounding .. but some customers request it

I'm not concerened with the grounding as much as the potential line noise created by the ground block and the extra connectors.

I can ground with no problem, but if the line noise isn't significant then I'm going to leave it as is.

[bwaldron]

I'm not concerened with the grounding as much as the potential line noise created by the ground block and the extra connectors.

I can ground with no problem, but if the line noise isn't significant then I'm going to leave it as is.

No line noise issues that I have ever seen, so long as quality connectors are used and the ground block isn't faulty.

[bigtiii]

No line noise issues that I have ever seen, so long as quality connectors are used and the ground block isn't faulty.

Connectors good....ground block of high quality.

Thanks for then info BW

[JonW]

The receiver doesn't use a 3-prong plug so it can't earth ground anything. If you don't ground the cable at all, then you may actually reduce the risk of drawing lightning, but the cable can build up high voltages from static induced charges and burn out your tuner. If lightning did strike, it could still be drawn in to the receiver depending what you hooked up to it - which is a serious safety risk.

Not only are they supposed to ground the cables, but there should be a unique wire copper run that grounds the dish. If you're worried about line noise due to ground loops, then have a dedicated AC circuit run to your AV room - or buy a UPS or power conditioner that isolates the AC. Heck, a cheap UPS would be more of a source of line noise.

[LameLefty]

The receiver doesn't use a 3-prong plug so it can't earth ground anything. If you don't ground the cable at all, then you may actually reduce the risk of drawing lightning, but the cable can build up high voltages from static induced charges and burn out your tuner. If lightning did strike, it could still be drawn in to the receiver depending what you hooked up to it - which is a serious safety risk.

Not only are they supposed to ground the cables, but there should be a unique wire copper run that grounds the dish. If you're worried about line noise due to ground loops, then have a dedicated AC circuit run to your AV room - or buy a UPS or power conditioner that isolates the AC. Heck, a cheap UPS would be more of a source of line noise.

Thank you for that. No one else seems to believe me that static is an issue with coax lines. I used to live on a hill and in dry weather, you can indeed build up static on exposed conductive surfaces, especially in a wind. Grounding the dish and a separate grounding block are a very good idea, period.

[JeffBowser]

+1 - I never understand the people that just brush grounding off like it is nothing (or the ones that think it does something about lightning :lol: ).

jb

Thank you for that. No one else seems to believe me that static is an issue with coax lines. I used to live on a hill and in dry weather, you can indeed build up static on exposed conductive surfaces, especially in a wind. Grounding the dish and a separate grounding block are a very good idea, period.

[armophob]

Here is a link that over informs on the subject.
http://www.dbstalk.com/showthread.php?t=84943

[Carbon]

Connectors (good ones) only insert a -2db loss . . . I think.

[bwaldron]

+1 - I never understand the people that just brush grounding off like it is nothing (or the ones that think it does something about lightning :lol: ).

Amen.

[K4SMX]

Last DTV installer put a ground block in my lines and I was wondering if they produce enough line noise that I should worry about it.


I was thinking if it does raise the noise level in the lines I'd just remove the block, ground the chassis of the Zinwell and get the block of the loop.

What say ye experts?
I wouldn't call myself an "expert," but I have been building and erecting antennas for 47 years, so at least you'd think I would have picked up the important stuff somewhere along the line. Do NOT remove your "grounding block," and make sure it's properly grounded to your house electrical service by as direct a path possible with #6 solid copper. If you have to run it all the way around your house, buried in the ground, that's OK. It should be at physical ground level, outside your house, and directly beneath your dish.

We have to distinguish between lightning protection, which is an oxymoron in many ways, and proper equipment grounding, which is designed to prevent transient equipment-damaging voltage differences from nearby lightning strikes. I feel at least marginally protected from fire or personal injury in a real lightning strike with nothing less than #4 solid copper (half-inch copper strap is preferred) running in as straight a line as possible directly from the antenna to an 8' ground rod, which is then tied to the service ground with buried #4 solid copper. So-called "grounding blocks" can be further grounded in the manner described above, after also running directly to ground. There should be no alternate lightning paths caused by routing coax through attic vents, etc. Additional coax is cheap compared to what you will be spending if this is not done properly and you get a direct hit.

I have seen what happens with direct lightning strikes to installations using what is minimumally "required." It may be legal, but I do not believe it is adequate. Outside antennas are inherently dangerous and this is serious business. We're talking about millions of volts and hundreds of thousands of amps. Volts x Amps = POWER. That's why I greatly prefer pole mounts. If you put a dish antenna on your roof, you have basically installed a lightning rod. You need a direct strike, if it comes your way, to go directly to a lot of metal in the ground, and hope you've done enough.

Grounding blocks, properly installed, will not cause "noise." In fact, failure to install them would in fact make that more likely.

[bigtiii]

I wouldn't call myself an "expert," but I have been building and erecting antennas for 47 years, so at least you'd think I would have picked up the important stuff somewhere along the line. Do NOT remove your "grounding block," and make sure it's properly grounded to your house electrical service by as direct a path possible with #6 solid copper. If you have to run it all the way around your house, buried in the ground, that's OK. It should be at physical ground level, outside your house, and directly beneath your dish.

We have to distinguish between lightning protection, which is an oxymoron in many ways, and proper equipment grounding, which is designed to prevent transient equipment-damaging voltage differences from nearby lightning strikes. I feel at least marginally protected from fire or personal injury in a real lightning strike with nothing less than #4 solid copper (half-inch copper strap is preferred) running in as straight a line as possible directly from the antenna to an 8' ground rod, which is then tied to the service ground with buried #4 solid copper. So-called "grounding blocks" can be further grounded in the manner described above, after also running directly to ground. There should be no alternate lightning paths caused by routing coax through attic vents, etc. Additional coax is cheap compared to what you will be spending if this is not done properly and you get a direct hit.

I have seen what happens with direct lightning strikes to installations using what is minimumally "required." It may be legal, but I do not believe it is adequate. Outside antennas are inherently dangerous and this is serious business. We're talking about millions of volts and hundreds of thousands of amps. Volts x Amps = POWER. That's why I greatly prefer pole mounts. If you put a dish antenna on your roof, you have basically installed a lightning rod. You need a direct strike, if it comes your way, to go directly to a lot of metal in the ground, and hope you've done enough.

Grounding blocks, properly installed, will not cause "noise." In fact, failure to install them would in fact make that more likely.


Thank you sir for this excellent info. Let me say that the installer that put in the ground block ran a wire to my copper pipes. Should I replace this wire and re-route to my ground pole outside? What guage wire would be sufficient? (I have some heavy romex I could scavange a good ground wire form). The installer from last week did not put a ground wire from the new dish BUT my dish is mounted low to the ground (below the siding line in the brick) and right by my home's electrical box (around the corner) and the ground pole right in the dirt next to the dish so adding a ground wire would be a breeze. I have some of that solid aluminum ground wire that came with some dish install kits I bought years ago....that work?


So while we are at it and as a little shift towards the lightning aspect....I installed two antennas (1 UHF/1 VHF) a year or so ago on a pole mounted to the roof. I have a CM7777 pre-amp that a knowleable friend said would blow if lightning struck those. Do you agree with that or should I run a wire from the antenna pole to the ground as well?


Thanks again for the help, I've got fair amount of general knowlege of installing and setups but since being here I've added some good info to the knowlege bank.

[bigtiii]

+1 - I never understand the people that just brush grounding off like it is nothing (or the ones that think it does something about lightning :lol: ).

jb

Dunno who you are talking to here but nowhere in my posts did I say I wasn't grounding, only trying to find the cleanest (best) way to ground. My statement about not being concerened about grounding was not saying I wanted to remove all grounding. I just want to know if I could ground properly without the block. I'm of the "less connectors is more" camp even if said connectors only add a couple of dB of noise in the lines. No one ever learned anything by not asking a question. I've learned something about you in one single post.

Carry on.

[bigtiii]

Here is a link that over informs on the subject.
http://www.dbstalk.com/showthread.php?t=84943

great link armophob........much appreciated :D

[LameLefty]

Dunno who you are talking to here but nowhere in my posts did I say I wasn't grounding, only trying to find the cleanest (best) way to ground. My statement about not being concerened about grounding was not saying I wanted to remove all grounding. I just want to know if I could ground properly without the block. I'm of the "less connectors is more" camp even if said connectors only add a couple of dB of noise in the lines. No one ever learned anything by not asking a question. I've learned something about you in one single post.

Carry on.

I think you're reading something in that post that wasn't intended. At least, I didn't take it as a stab at you personally.

[JeffBowser]

Whoa, relax there dude, I wasn't talking about you in that post.

I have also learned something about you in one single post - you jump down my throat with no provocation whatsoever :confused:


Dunno who you are talking to here but nowhere in my posts did I say I wasn't grounding, only trying to find the cleanest (best) way to ground. My statement about not being concerened about grounding was not saying I wanted to remove all grounding. I just want to know if I could ground properly without the block. I'm of the "less connectors is more" camp even if said connectors only add a couple of dB of noise in the lines. No one ever learned anything by not asking a question. I've learned something about you in one single post.

Carry on.

[bigtiii]

Whoa, relax there dude, I wasn't talking about you in that post.

I have also learned something about you in one single post - you jump down my throat with no provocation whatsoever :confused:

no sweat, I stand corrected.......but please don't read "jump" into a post where there is no jump. I'm calm at the keyboard.

[rlgold88]

The receiver doesn't use a 3-prong plug so it can't earth ground anything. If you don't ground the cable at all, then you may actually reduce the risk of drawing lightning, but the cable can build up high voltages from static induced charges and burn out your tuner. If lightning did strike, it could still be drawn in to the receiver depending what you hooked up to it - which is a serious safety risk.

Not only are they supposed to ground the cables, but there should be a unique wire copper run that grounds the dish. If you're worried about line noise due to ground loops, then have a dedicated AC circuit run to your AV room - or buy a UPS or power conditioner that isolates the AC. Heck, a cheap UPS would be more of a source of line noise.

My hr20 700 doesn't have the 3 prong plug but the hr20 100 does have the 3 prong which gave me a hum problem that was fixed by correctly grounding my grounding block and sat.
I didnt have the problem until the hr20 100 was connected. Grounding correctly fixed the humming.

[Ext 721]

Dunno who you are talking to here but nowhere in my posts did I say I wasn't grounding, only trying to find the cleanest (best) way to ground. My statement about not being concerened about grounding was not saying I wanted to remove all grounding. I just want to know if I could ground properly without the block. I'm of the "less connectors is more" camp even if said connectors only add a couple of dB of noise in the lines. No one ever learned anything by not asking a question. I've learned something about you in one single post.

Carry on.

I suspect the best and cleanest method would be to have a whole-home power conditioner (never seen one but i hear they exist)professionally installed at or around the service entrance by a properly licensed electrician, and to have all grounding done with the cleaned-up house ground.

If that's a pipe dream, or inherently flawed, I'll gladly stand corrected.

[K4SMX]

Thank you sir for this excellent info. Let me say that the installer that put in the ground block ran a wire to my copper pipes. Should I replace this wire and re-route to my ground pole outside? What guage wire would be sufficient? (I have some heavy romex I could scavange a good groundwire form). The installer from last week did not put a ground wire from the new dish BUT my dish is mounted low to the ground (below the siding line in the brick) and right by my home's electrical box (around the corner) and the ground pole right in the dirt next to the dish so adding a ground wire would be a breeze. I have some of that solid aluminum ground wire that came with some dish install kits I bought years ago....that work?

So while we are at it and as a little shift towards the lightning aspect....I installed two antennas (1 UHF/1 VHF) a year or so ago on a pole mounted to the roof. I have a CM7777 pre-amp that a knowleable friend said would blow if lightning struck those. Do you agree with that or should I run a wire from the antenna pole to the ground as well?

Thanks again for the help, I've got fair amount of general knowlege of installing and setups but since being here I've added some good info to the knowlege bank.
The copper pipe ground for your ground block is probably OK, but you never know for sure there's not PVC in there somewhere. Your dish is probably OK, too, since it's close to the house at ground level. Certainly wouldn't hurt to ground it to a nearby CW pipe, if there's one handy. However, any separate ground for it must be bonded to the house service ground with #6. You can have at pulling your Romex apart. As for the OTA on the roof, I think it's pretty clear from my comments what I think about that! You'll also need to run the feedline(s) for it through a properly installed ground block, grounded in the proscribed manner.

[bigtiii]

The copper pipe ground for your ground block is probably OK, but you never know for sure there's not PVC in there somewhere. Your dish is probably OK, too, since it's close to the house at ground level. As for the OTA on the roof, I think it's pretty clear from my comments what I think about that! You'll also need to run the feedline(s) for it through a properly installed ground block, grounded in the proscribed manner.

My house is PVC free so in that case I'll skip the re-route. Thanks.

I'll purchase a ground block. With my CM7777 pre-amp the added noise shouldn't hurt right? Is there an alternative to the ground block? My antenna pole is easy to reach so would it be the same to run a ground wire from the pole to the ground? Sorry to keep beating this ground block horse :) but I guess I want to be clear is it about grounding the antenna assembly or making sure the coax is grounded properly. Can I assume that this grounding has more to do with lightning than with electrical?

[JeffBowser]

All is well, cheers.
:)

no sweat, I stand corrected.......but please don't read "jump" into a post where there is no jump. I'm calm at the keyboard.

[aim2pls]

Connectors (good ones) only insert a -2db loss . . . I think.



0.5 (insertion loss)

[K4SMX]

My house is PVC free so in that case I'll skip the re-route. Thanks.

I'll purchase a ground block. With my CM7777 pre-amp the added noise shouldn't hurt right? Is there an alternative to the ground block? My antenna pole is easy to reach so would it be the same to run a ground wire from the pole to the ground? Sorry to keep beating this ground block horse :) but I guess I want to be clear is it about grounding the antenna assembly or making sure the coax is grounded properly. Can I assume that this grounding has more to do with lightning than with electrical?
You can quit worrying altogether about "added noise." The antenna pole should be grounded with a #4 solid copper straight down to an 8' ground, which is further bonded to the service ground. The OTA coax line(s) should come straight down to the ground block, and the ground block should be bonded to the ground rod and house service line "back path," all at the same point.

Gotta go cook ribs for six now...Wood fire, and all that! Great quote:"Believe you me, real barbeque does NOT start with the turn of a knob..."

[bigtiii]

0.5 (insertion loss)

So for a single wire on a ground block does each male and female portion of the assy create .5 db loss for a total of 2db or is it only for the connectors on the cable and a total of only 1db loss?

[bigtiii]

You can quit worrying altogether about "added noise." The antenna pole should be grounded with a #4 solid copper straight down to an 8' ground, which is further bonded to the service ground. The OTA coax line(s) should come straight down to the ground block, and the ground block should be bonded to the ground rod and house service line "back path," all at the same point.

Gotta go cook ribs for six now...Wood fire, and all that! Great quote:"Believe you me, real barbeque does NOT start with the turn of a knob..."

"Ah I see" said the blind man.

I gots me 2 grounds to run.

Thankee sir...........and boy you said it....I turn a knob when I "bbq" and my dad fires up his ceramic egg, man what a difference. Enjoy, you've earned it with me today.

[renen]

Gentlemen,

I reinstalled my dish after the installer completed the upgrade to the slimline about a month ago, at the time I replaced the 18 gauge grounding cable with #4 stranded wire to both the grounding block and the dish.

Now, could anyone tell me why is the grounding wire supposed to be solid as K4SMX explained? Could I use stranded instead as long as it is thick (heavy)enough?

Is this related to my Physics classes many years ago where the strands of a cable with a LOT of current would be separated by the electromagnetic field of similarly charged strands, as the voltage tends to travel on the surface of each strand repelling each other?

Rene

[ilfn143]

inside the lnb is a lna (low noise amplifier) inside the receiver is another lna with alc (auto level control) any loss due to cable/connector will be compensated. so i wouldn't worry about any loss. wind blow across the dish will generate static, it'll burn stuff inside lnb (mixer,oscillator,lna...) if doesn't get drain off.

[K4SMX]

Gentlemen,

I reinstalled my dish after the installer completed the upgrade to the slimline about a month ago, at the time I replaced the 18 gauge grounding cable with #4 stranded wire to both the grounding block and the dish.

Now, could anyone tell me why is the grounding wire supposed to be solid as K4SMX explained? Could I use stranded instead as long as it is thick (heavy)enough?

Is this related to my Physics classes many years ago where the strands of a cable with a LOT of current would be separated by the electromagnetic field of similarly charged strands, as the voltage tends to travel on the surface of each strand repelling each other?

Rene
Some people think that the inevitable oxidation on the outside of each strand makes it unsuitable for outdoor use. My house lightning rods are grounded through the 1/2" diameter "mesh" stuff. I really think any oxidation would be instantly vaporized during a lightning strike. Oxidation is really only probably an issue in low voltage ap's. As a matter of fact, with respect to #4 stranded, the whole wire would probably be vaporized in a really big strike. That's why the copper strap is better. Use the biggest wire you can get your hands on/afford.

[aim2pls]

So for a single wire on a ground block does each male and female portion of the assy create .5 db loss for a total of 2db or is it only for the connectors on the cable and a total of only 1db loss?

device total is 0.5 ... i know its confusing but thats the way it is ... a F-81 (ground block) or a splitter with 2 F-connectors is 0.5 insertion loss

[gresmi]

device total is 0.5 ... i know its confusing but thats the way it is ... a F-81 (ground block) or a splitter with 2 F-connectors is 0.5 insertion loss

Are ground blocks needed if the multiswitch is grounded?

[JonW]

You can quit worrying altogether about "added noise." The antenna pole should be grounded with a #4 solid copper straight down to an 8' ground, which is further bonded to the service ground. The OTA coax line(s) should come straight down to the ground block, and the ground block should be bonded to the ground rod and house service line "back path," all at the same point.

On a sidenote, the dish installation instructions call for the dish to be grounded by a run of solid copper wire. When they recently worked on my install, they used some RG-6 cable that a solid copper ground built-in to the cable. Originally they used standard RG-6 and I had to insist they run a separate piece of copper.

There is an art to lightning protection, and there is a trade-off between designing to avoid lightning .vs. designing to survive a strike .vs. designing to survive a nearby strike; but this isn't something a directv customer should be worried about. Just make sure the installers install ground blocks on each coax *AND* run a piece of solid copper to ground the dish. This is what they're required to do.

The blocks and ground wire *should* be connected to a ground stake. If they bring the wiring down on the opposite side of the house, I believe they may be required to install a secondary ground round and run a wire to connect the two rods - but I'm not positive. Just avoid this if at all possible. Try to have the point of entry where the ground rod is.