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Bluetrue

join:2006-08-22
Powhatan, VA

[DW7000] Using messenger wire to ground system?

My installer finally admitted that my system is not grounded properly. Now they want to redo all of the cableing. However, instead of using quad shield, they want to use dual coax with a "messenger" wire. They want to run the dual shield from the dish to close to the electrical service and install an 18 inch ground wire from the ground block to the service ground. So far so good (although the total cable length will be about 175 feet). However, to ground the dish and radio, they want to use the messenger wire to connect from the dish to the ground block. I have read mixed opinions on this. Should I insist that they use a copper ground instead? I am willing to buy it myself if that is what it takes.



anectine17
Premium,MVM
join:2003-01-05
Mountain Home, ID

IMO, the dual coax is fine as long as it's quality, solid copper core. The Wild Blue forum has a list of approved brands that meet their requirements. Others (Greg) will disagree and maintain that quad-shield is necessary on all installs. It's nice, but it's over-kill in my opinion....at least in most situations.

As for the messenger wire as ground...NOOOOOOO. It's not heavy enough gauge for starters. I believe 14 is required as minimum, and the messenger wire is probably 18 at best. Additionally, the messenger wire is probably copper-clad steel instead of solid copper. There's no reason you should have to pay for the proper materials either. Insist they do it right. Go to the link below and scroll through the downloads and find the install manuals. The original DW4000 install manual has the best description of grounding requirements that I know of. Print that and hand it to him. Tell him to read the grounding requirements and that you want yours to meet that standard. It requires 14 gauge ground wire. Good luck!!

Alden

»www.montanasatellite.com/downloads/index.htm
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HN7000S ProPlus | G16/970 | Gtwy 66.82.156.50 | Static IP | .74m Dish | FF 1.5 | Wired/Wireless Network w/ Modded Linksys WRT54GS v.2 w/ DD-WRT | Asus P4S800/Celeron-D 2.8ghz (OC'd to 3.4) Home-Built Desktop | Inspiron 1150 Laptop | Multi-Layered Security



grohgreg
Dunno. Ask The Chief

join:2001-07-05
Dawson Springs, KY

4 edits
reply to Bluetrue

said by Bluetrue:

...instead of using quad shield, they want to use dual coax with a "messenger" wire. They want to run the dual shield from the dish to close to the electrical service and install an 18 inch ground wire from the ground block to the service ground. So far so good (although the total cable length will be about 175 feet). However, to ground the dish and radio, they want to use the messenger wire to connect from the dish to the ground block.
I gotta say that your description has me completely baffled. If the dish is close enough to your service entrance to use an 18" ground wire, why on earth bother with an otherwise useless "messenger ground"? And 175 feet of it as well !! I don't get it.

Messenger wire is a functional component of aerial cable, meant to support the weight of the attached cable. Because if/when the center conductor is permitted to stretch, its resistance value increases as the gauge (diameter) decreases. Result - signal attenuation. If/when the shielding is permitted to stretch, it will simply break and separate. Result - loss of signal ground path. The sole purpose for messenger wire is to prevent stretching of suspended cable. Besides that, messenger wire is typically 17ga steel, not even copper clad. Hughes requires ground wires to be minimum 10AWG copper or 6 AWG aluminum.

Aerial cable is also UV-resistant, since it's assumed to be typically installed in direct sunlight. But aerial cable is NOT flooded - which means it does not have the waterproofing necessary for direct bury applications. I think you'd grow old trying to find flooded (direct bury) cable with a messenger wire, that is otherwise suitable for use with a HughesNet system.

Even though FSB 050518.1C suggests it's an acceptable installation procedure, I strongly disagree with Hughes about running the ODU ground wire through the cable block. The wire between the ODU and common ground represents the electrical ground (primary DC return path and lightning prevention). The wire between the cable block and common ground represents the signal ground (DC zero reference and alternate DC return path). The two should NOT intersect, except when both ultimately arrive at the common ground. And it's best when the distance between the cable block and the modem is LONGER than the distance between the cable block and the common ground point.

Alden - relative to your comments, I do endorse the general use of QuadShield, but not for the reason you imply. There is nothing to support an assumption that QS is universally better on longer runs. QS is engineered primarily as a low noise cable, nothing else. The key to long cable runs is to actual READ the specs on the cable before you even buy it. If it has an acceptable loss figure, whether or not it's of QS construction - is irrelevant. Example; Hughes FSB 060316.1a approves CommScope 5729 (dual shield) for 1 watt runs up to 276 feet. They approve Perfect10 Quad for 1 watt runs up to 277 feet. So you can see in this case, there's no "length" advantage to using that particular quad cable.

As a side note, I also strongly disagree with Hughes FSB 060316.1a where it implies Quad shielding provides a viable electrical ground path. As above, shielding should be relied upon for signal ground only. Solid copper or aluminum should be the default electrical ground, all the way from the ODU to common.

//greg//
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DW4000CE/1.2Ghz Tualatin/1GB PC133 - W2K Pro/SP4 - SRS G11/1410H - RSL78/ACP82 - v4.2.1.10C - RWIN 513920/MTU 1500 - Gateway/66.82.10.xx/DNS66.82.4.8 plus rollovers - Firefox 1.506/proxy switch - AVG7.1 plus Firewall

Bluetrue

join:2006-08-22
Powhatan, VA

said by grohgreg:

I gotta say that your description has me completely baffled. If the dish is close enough to your service entrance to use an 18" ground wire, why on earth bother with an otherwise useless "messenger ground"? And 175 feet of it as well !! I don't get it.
Thanks for your response - very helpful. Just to clarify, the dish is about 80 feet away from the electical service entrance. So the ground would have to go 80 feet to the ground block. They then have to go about 120 feet back to the side of my house and up the side to the attic and then down to the modem. Total cable length is actually around 200 feet.

The 18" ground wire is from the ground block to the service ground.


grohgreg
Dunno. Ask The Chief

join:2001-07-05
Dawson Springs, KY

1 edit

duplicate post



grohgreg
Dunno. Ask The Chief

join:2001-07-05
Dawson Springs, KY

1 edit
reply to Bluetrue

said by Bluetrue:

the dish is about 80 feet away from the electical service entrance. So the ground would have to go 80 feet to the ground block. They then have to go about 120 feet back to the side of my house and up the side to the attic and then down to the modem. Total cable length is actually around 200 feet.
I can't believe they'd be so untrained as to even consider a solution like that. The correct method is
1. 80' of (min) 10AWG solid copper from ODU to common ground at the electrical service entrance
2. 120' of Hughes-approved RG6 to the cable block,
3. xx' of the same RG6 from the cable block to the modem
4. then run ANOTHER ground wire from the cable block to the electrical service entrance ground
a. if the distance from the cable block to the common ground is 20' or less, use the same kind of ground wire (10AWG)
b. if the distance from the cable block to the common ground is over 20', the installation becomes subject to a NEC article that requires an approved supplemental electrode (ground rod) at or before the 20' mark. The supplemental electrode must then be bonded to the service entrance common ground with 6AWG copper.

//greg//


wycolo
Heaven Starts Here At 9000 Feet.
Premium
join:2005-11-11
Laramie, WY

Greg,
I have scenario # 4b.

My home service entrance ground is way over 20 feet.

I currently have a 8'X 5/8" ground rod pounded into the ground all but 6".

I have the ground cable block about 6 feet from the transmitter unit(From original install) then 70 feet or so to the modem.

The ground block is grounded to the rod and the transmitter is directly grounded to the service entrance about 80 feet.

I had to bury the ground wire that goes to the service entrance to protect it from being damaged .
My question is, is all this ok?.

Would the buried #6 solid copper wire throw off the grounding impedance different from the actual service going to the home due to being underground 80 feet to the service entrance?

Since it has to be buried to protect the ground wire from being damaged, should it be a shielded #6 solid burial type copper wire?
Thank you.



grohgreg
Dunno. Ask The Chief

join:2001-07-05
Dawson Springs, KY

1 edit

Your cable block is in the wrong place. Hughes FSB 050518.1c requires that Ground Blocks be installed inside the building within 5 feet of the point of entry". From there, items 4a and 4b above apply.

Incorrect installation notwithstanding, burying copper doesn't hurt a thing. It's aluminum that has the ground contact limitations.

//greg//
--
DW4000CE/1.2Ghz Tualatin/1GB PC133 - W2K Pro/SP4 - SRS G11/1410H - RSL78/ACP82 - v4.2.1.10C - RWIN 513920/MTU 1500 - Gateway/66.82.10.xx/DNS66.82.4.8 plus rollovers - Firefox 1.506/proxy switch - AVG7.1 plus Firewall