Grounding Info & Standards: OTA/Dish/CATV/Telecom

[stampeder]

Here's a previous thread that might be of interest to OTA and CATV installers (not including Satellite) about whether to replace old, pre-existing RG59 coax cable with RG6 (I say its better to switch to RG6 if you are having troubles with your RG59 and you can afford to replace it):

http://www.digitalhomecanada.com/forum/showthread.php?t=25419

[jbracing24]

Should an incoming outdoor antenna cable pass through any kind of surge protector before connection to a DT tuner?
I have a 30ft tower with a CM 4228 and a Samsung 451. I know the tower should be grounded because it is buried at the base. Most of my HT equipment is plugged into an APC 8 outlet surge protector. The surge protector has an RF style input and output marked Sat/Cable. Would there be any value in using this on the antenna cable run? What about signal loss? I am more concerned about lightening than other electrical surges.
Comments welcome

[Tom.F.1]

Your incoming line from the antenna has to (MUST) go thru a ground block. This ground block must be grounded, preferably to a ground rod. Then you have a place to put your lightning arrestor.
I'd keep the ground block outside, immediately before you enter the house with the coax.
You can use a water pipe inside, but do you really want to bring a lightning strike inside your house to get to ground?

[jbracing24]

I found this information on hdtvprimer.com...

Lightning arrestor - A lightning arrestor is a device that protects the equipment. It has a set of points or gas-discharge devices that will arc-over when a high voltage is present. A lightning arrestor is important when the feed-line is twin-lead. But coaxial systems don’t usually have lightning arrestors because the center conductor rarely acquires a high voltage, and the shield conductor is usually grounded directly.

[jbracing24]

The same source had this advice...

Grounding outdoor antennas
For TVs, the main benefit of grounding is lightning protection. Lightning is a powerful radio wave generator and any elevated wire is an antenna for it. A lightning strike in your neighborhood can generate hundreds of volts, even thousands, on the coaxial line. These voltages can damage your equipment.

To reduce these voltages the antenna cable should have a grounding block (Radio Shack 15-509) at the point where it enters the house, and that grounding block should be wired to a ground rod driven into the ground as close as possible to the grounding block. An effective ground rod is one driven deep enough to reach into moist soil.

The ground rod should also connect to the mast via a heavy wire. #8 aluminum wire (Radio Shack 15-035, $7) is readily available for this. Ground wires should be as short and straight as possible. Turns should be curves with a 6-inch radius. Ground wires do not need insulation.

Some people will tell you “Don’t ground the coax. That just makes the antenna a lightning rod”. But the coax is already grounded through your receiver’s power cord, so you can’t prevent it from being a lightning rod. All you can control is how much of your house the high current will go through before it reaches the ground.

Does this advice also apply to tower installations? Comments welcome. The installer didn't seem to be concerned about this issue.

[jbracing24]

Originally Posted by Tom.F.1

Your incoming line from the antenna has to (MUST) go thru a ground block. This ground block must be grounded, preferably to a ground rod. Then you have a place to put your lightning arrestor.
I'd keep the ground block outside, immediately before you enter the house with the coax.

Well, I spent part of the midnight shift "Googling" the subject.

Winegard notes that a ground based installation must extend four or more feet into the ground to be an effective "ground". Since my tower is only 1 1/2 ft in the ground, it is not considered "grounded". So, the advice I previously posted will have to be followed.
So, as Tom.F.1 noted, a ground block should be installed at the cable entrance, a #8 aluminium wire attached running to a 4 foot ground rod nearby. Also the tower needs to be connected in the same manner to the ground rod.
School is out on a further connection from the grounding rod to the breaker box ground with 6 gauge copper wire. The National Electrical Code in the US requires it, since in a direct hit, part of the charge could build up in the ground between the house ground and the grounding rod. Wineguard agrees but Channel Master differs.
Singapore Science Centre site goes further, after recommending a proper grounding, to use a quality surge suppressor with coax protection. If properly rated, they can react quickly by absorbing large surges of current before it gets to sensitve equipment.
Orlando Digital TV site notes that inline coax arrestors will help with near hits but with a direct strike generally, nothing survives. If the voltage is high enough, the arrestor will generally burn itself out and shortly afterward your equipment. Nice!!!

Looks like I will be shopping for a ground block, #8 wire, clamps and a grounding rod. The effort to run a wire around the house to the house ground may not be practical.

[Yaamon]

I grounded mine with a coax block and also grounded the base of the antenna.

Connected both into a 4' copper treated rod that I drove into the ground.

A note if you are using a preamp like the 7775 it also has protection from lightning and surge.

The thing you have to remember if lighting happends to hit the antenna directly, no ground wires is going to prevent power surge from coming through the wires and into the equipment that may cause damage.

By grounding a antenna what you are doing is basically bleeding off any electrical/static discharges in the air and bleed it off to the ground, when you have bad weather.

I dont think any 8 gauge or thicker is going to bleed off hundred and thousands of volts fast enough.

[jbracing24]

Originally Posted by Yaamon

I grounded mine with a coax block and also grounded the base of the antenna.
Connected both into a 4' copper treated rod that I drove into the ground.

I drove a 4 ft ground rod at the base of the tower and connected a short piece of 8 gauge high current wire to the tower. I spliced the coax, just before entering the house with a ground block and used the 8 gauge wire from the ground block to the rod. Inside, I ran the coax through a surge protector, before attaching to the Samsung.

I also ordered a TII in-line coax protector, which is a gas tube surge arrester connected to a gound block. This type of unit came recommended by a friend who works in commercial networking and communications (involved with communications towers ei. Minolta Tower etc,) He said this kind of arrester has saved his butt more than a few times. This will replace the ground block now installed.

As you say, nothing will survive a direct hit, but the insurance company might just be a little more sympathetic if you take all the measures you can.

[stampeder]

There's a thread in the Home Theater Corner Forum about using Coax cable:

http://www.digitalhomecanada.com/for...ad.php?t=33244

[Murray OTA]

I've read that when using an outdoor antenna mast that it should be grounded by connecting it to a ground rod using a heavy wire (#8 aluminum wire). What is the best method of connecting the wire to the mast?

By searching the net, I found a Canadian site that sells what they call a "grounding wire pipe clamp" at www.mycableshop.ca/sku/200-296.htm. Is this the way to go? Do they sell anything like this at Home Depot or any other local hardware store?

Any advice would be appreciated, thanks.

[Brewmaser]

That type of grounding clamp is available at most hardware stores. I believe there is info about grounding somewhere in the FAQ's on this site.

[HDTV101]

Originally Posted by Brewmaser

That type of grounding clamp is available at most hardware stores. I believe there is info about grounding somewhere in the FAQ's on this site.

This is my grounding ... the clamp was bought at Rona in the electrical department along with the #6 green ground wire. The satellite dish is also grounded using a lug connector under one of it's bolts.

[Murray OTA]

Is the ground wire that comes attached to some brands of RG6 sufficient to use for grounding your antenna mast? All the info (packaging) I have found refers only to grounding a Sat Dish with no mention of using it for an antenna mast.

[stampeder]

Murray, antenna masts tend to project several feet higher or more into the air than satellite dishes so in my opinion the ground line from that kind of coax (usually its 16 or 18 AWG) is too skimpy. To be really sure, you probably want to go with 10 AWG at least.

[j2k]

Hi everyone!

I'm planning to move my antenna from my garage to the roof of the house. I found that my cable tv is grounded (from a splitter) to a grounding rod by my house.

The grounding rod is sticking maybe 20 cm from the ground and is very close to the building (maybe 2 cm away from the wall, looks like it might be touching the brick in one spot). I am wondering if this location is suitable or if it should be further from the building. Also is there any way to verify that this grounding rod is actually a proper ground (without digging it out)?

Or would it be safer to just put a brand new grounding rod? If yes, then are there any rules when choosing its location?

One more question - when grounding the mast, does it matter if the wire is copper, aluminium, solid or stranded as long as it is thick enough?

Thanks!