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Guest Message by DevFuse

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Tower Installation


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34 replies to this topic

#21 OFFLINE   babzog

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Posted 16 July 2008 - 04:20 PM

Thanks again for all the good info.. lots of reading to do later!

Christopher - beautiful installation! I've actually angled the tower so that the corner, rather than a side, is facing to the SW. Can't move it now. :) Not sure if I can rig it like yours. I see you also use the additional bracing. I'd hoped to get away without having to add that bracing but it appears that most installs are using them.

Was checking into prices for grounding rods and wire. At HD, I can get copper (copper clad steel, I beleive - they're quite heavy) or galv. ground rods. The galv rods are quite a bit cheaper than the copper. Given that I need three of 'em for the tower, should I go with the copper or are the galv. rods fine? The soil turns into wet clay about 3' down.

Also, HD has 3/O (3-ought) copper cable - about as thick as my finger! For grounding each of the tower legs, better to go with as large a cable as I can find, or is #3 or #6 enough?

For bonding the rods together and then that ring to the house... #6 is the min. required. Does that mean that's sufficient or should one go larger?

Finally... ground rod ends and all ground wires can be buried?

Cheers!
Jon

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#22 OFFLINE   Christopher Gould

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Posted 16 July 2008 - 05:29 PM

Thanks, Christopher. You're the guy with the photos I was trying to find. Rock solid installation. I wouldn't want to stumble into it in the dark!


the dish itself is about 6'0 high. I'm 5'10 and can step under it to mow. :)

#23 OFFLINE   K4SMX

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Posted 17 July 2008 - 12:06 AM

I'd recommend the copper-clad steel ground rods. An alternative to the ring is to space one rod about a foot or two out from each tower leg. It was explained to me long ago by a very bright senior engineer at Bell Labs, now deceased, that this has the same electrical effect as driving a single, gigantic triangular-shaped ground "rod," with a large amount of lightning dissipation capability.

Use the 3 ought with multiple stainless steel hose clamps at the tower legs and the brass ground rod clamps, also available at the Homeless Depot. Smear Noalox all over everything. Yes, you can bury the wires and rods.
Stew in Florida

HR21-100 (eSATA: Seagate Barracuda 750gb/Antec MX-1), Mitsubishi LT-46131 (HDMI), Onkyo A/V (optical), Slingbox Pro/WLI-TX4-G54HP
HR20-700 (eSATA: FreeAgent Pro 750gb), Mitsubishi LT-46131 (HDMI), Pioneer A/V (optical)
HR20-700, Mitsubishi LT-37132 (HDMI), Sony A/V (optical)
HR20-700, Mitsubishi WD-65731 (HDMI)
H20-600 (x 2)

#24 OFFLINE   brant

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Posted 17 July 2008 - 12:23 AM

to be honest, there's no need to use the copper-clad rods. galvanized rods work just fine. multiple grounding electrodes must be spaced at least 6' apart because of the 3' step potential radius around them. noalox is for aluminum connections. #6 copper is all that is required for a grounding conductor in this setup. the rods (along w/ their connectors) are to be driven below grade.

being that you're getting this wire cut to length, you may want to try an electrical supply house; the big box stores are outrageously expensive on wire cut by the foot. being you're not a contractor, you may or may not get a better price. but you can call ahead and ask.

you can drive all the rods you want and use the biggest conductor you can afford, but there's not much you can do in the event of a direct strike. the only thing you've got coming into the house is the TV coax and i'm assuming something like LMR400 coax for the internet (i have a camvera networks system; probably very similar to what you have for the wireless). you may want to use inline surge suppressors on your coax or get surge suppressors at each wall outlet that have protection for the coax built in. also use a suppressor at your computer w/ in & out for patch cable coming out of the modem.

#25 OFFLINE   K4SMX

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Posted 17 July 2008 - 01:08 AM

The ground rods in the example I gave are intentionally spaced close together because electrically it looks to lightning like a single, solid conductor with a very large surface area.

The Noalox is for where the copper ground wire meets the zinc galvanization on the tower leg. It works for zinc, too, but it's not a high priority item. If the zinc gets eventually eaten away, it'll be a long time before the steel rusts. :)
Stew in Florida

HR21-100 (eSATA: Seagate Barracuda 750gb/Antec MX-1), Mitsubishi LT-46131 (HDMI), Onkyo A/V (optical), Slingbox Pro/WLI-TX4-G54HP
HR20-700 (eSATA: FreeAgent Pro 750gb), Mitsubishi LT-46131 (HDMI), Pioneer A/V (optical)
HR20-700, Mitsubishi LT-37132 (HDMI), Sony A/V (optical)
HR20-700, Mitsubishi WD-65731 (HDMI)
H20-600 (x 2)

#26 OFFLINE   brant

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Posted 17 July 2008 - 07:04 AM

i'm not sure the lighting is going to know or care how far apart the rods are; its looking for the path of least resistance. the NEC requires 6', and to get away with doing otherwise usually requires the services of an engineer.

#27 OFFLINE   babzog

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Posted 17 July 2008 - 09:08 AM

I was surfing around last night to see if there were any considerations of one type of rod vs another. Seems that acid soils require the use of galv. rods (acid eats the copper) and alkaline soils require the use of copper rods. A soil map of my area seems to indicate that the soils are typically acidic. Will need to test further to verify.

Bury it all .. great! :)

Reason for pondering the 3 ought cable (for the leg-rod connections) is to provide a nice path to ground as I would think a strike would vaporize the #6, but if #6 is sufficient, I'll go with that.

Oddly, my calls to local electrical service suppliers are yielding results in line with HD. Sometimes HD is better, sometimes not. ie: they're better for galv. rods (by nearly $10 ea) but are lousy on wire prices. OTOH, I can only buy #10 ground wire by 1000' spool from the supplier and by the foot from HD. I'll be shopping around, picking up the components from here and there. :)

Internet service is via RG6 from the antenna to a standard cable modem with cat5 to my router.

Update: Just got word back from my ISP... they can run up to 300' of cable, so no worries! Woot!

#28 OFFLINE   brant

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Posted 17 July 2008 - 01:51 PM

you're not going to stop the power of a direct strike; 3/0 doesn't stand a chance any more than #6 (something that can vaporize the water inside of a nonconductive tree is going to cause massive damage to copper). you're trying to give a path for the transient voltages. #6 is certainly a better path than rg6. put surge suppression devices on your equipment in the house (the cable modem, receivers; tv's, etc. . .) and put inline surge suppressors on the coax.

just out of curiosity, do you know what type of wireless internet system you are on? mine is camvera; it doesn't work w/ a cable modem though. I have lmr400 coax coming from the antenna into a navini networks wirelss modem.

#29 OFFLINE   babzog

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Posted 19 July 2008 - 12:53 AM

Tested the soil today (let some soil soak in distilled water overnight and tested with the pool kit). Seems it's slightly alkaline (even though a soil map indicates the soils are generally acidic in my area). Oh well.. can't argue with test results. :) Copper rods it is.

Found a good site for calculating how much wire can fit in a conduit: Designing Conduit Runs

They don't mention though (other sites do) that you should subtract 15% off the allowable fill for each 90deg elbow. If I stick to 2 elbows, then the 1.5" conduit (as suggested earlier) will be perfect for up to 7 runs. If I go with three elbows, then I have to bump up to 2" conduit or reduce the # of runs.

Then it struck me... I could use one of these:
Posted Image
to connect to my vertical riser at the tower and then horizontally into the enclosure at the tower base. This should give me access for pulling, reducing the # of elbows to 2 and reduce my conduit size from 2" to 1.5" (saves me enough to buy a weatherproof box). I think it looks neater too, esp. when compared to a 90deg elbow arching over the edge of the foundation.

Do you foresee any problems with this approach?

#30 OFFLINE   babzog

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Posted 19 July 2008 - 01:00 AM

Hey Brant,

Do I know the type of wireless. Sorry, no I really have no idea, other than it's in the 5GHz range, employs a cable modem as my interface and uses pppoe on the network.

#31 OFFLINE   babzog

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Posted 19 July 2008 - 01:07 AM

I now have the materials (save the rods which I'll pick up tomorrow) to build up the grounding system. Picked up a pile of #6 for the bonding wires and some #3 for the tower leg - rod connections (made me feel a little better going to a slightly higher gauge). Couple of questions regarding attaching grounding wires to rods though, before I begin:

How many wire connections am I permitted per clamp?

Can I run the bonding wire from house to the tower and run around the ring using one contiguous piece of wire or should I cut the wire and separate the tower's ring wire from the ring-house wire (even though they'd still be clamped to the same rod)?

The supply house only had aluminum connectors (for attaching the copper to the galv tower legs). Are there are problems attaching aluminum to galv. metal?

How close should I drive a rod to a newly buried phone wire (that's been run to about 2yrd from the tower's foundation)? The phone line is going to be buried in the same trench as the conduit, which is the reason for routing it in this fashion.

Many thanks again!
Jon

#32 OFFLINE   brant

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Posted 19 July 2008 - 10:25 AM

leave the ground wire continuous; just loop it through the ground rod clamps.

i'm not a big fan of the aluminum connectors, but if that's all they had. . .

the rod is fine next to the phone line.

that pvc box you linked a pic of is called an LB. works fine.

#33 OFFLINE   Stuart Sweet

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Posted 19 July 2008 - 11:04 AM

As the original poster is talking about a DIRECTV dish, I'm moving this back to DIRECTV installation.
Opinions expressed by me are my own and do not necessarily reflect
those of DBSTalk.com, DIRECTV, DISH, The Signal Group, or any other company.

#34 OFFLINE   brant

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Posted 19 July 2008 - 01:12 PM

As the original poster is talking about a DIRECTV dish, I'm moving this back to DIRECTV installation.



huh? that's where its been since its inception.

#35 OFFLINE   kycubsfan

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Posted 07 November 2008 - 08:20 PM

Any progress of late? I'd like to see some pics of the finished product.




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