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Old 23-Jul-2013, 11:54 AM   #1
Wake49
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Moving Attic Antenna outside, looking for grounding advice

Hello all, may report: http://www.tvfool.com/?option=com_wr...46ae4f45b516fa

In December I made the move to cut the cable. My alternative is a Roku box with Hulu, Netflix and Amazon and OTA reception. I bought an RCA ANT751R and mounted it in the attic. When I was only getting two channels to start (NBC would come in spotty to make it three) I added a preamplifier: RCA PRAMP1R to boost the signal and ended up with maybe four or five stations (plus substations, so maybe 12 channels total).

I went on to research antennas and how they work and found a good DIY bowtie style antenna. I built one of these with a reflector and put that in my attic. Now I can get FOX, CBS and PBS, but only sometimes. FOX only comes in perfect during the day (three bars), at night it is one bar at best. CBS (four bars at best) isn't reliable and I can miss large chunks of shows if it starts getting spotty. Obviously ABC comes in great (six to seven bars) and NBC is also consistent (five bars). The other stations, (Real 39 and Real 20 and their subs, mainly) come in good (four to five bars).

Here are my two questions: I want to move the antenna outside and picked up a Wineguard Gable Mount (off Amazon, it is due to me on Wednesday) and a 1" mast. I am moving the RCA antenna outside since (a) it is not doing anything but collecting dust and (b) I didn't really build the DIY one for outside use; I am afraid it will blow apart with the first strong breeze...

First question: Does anyone have and use the RCA751R and can you attest to its abililty to get stations that are 20-30 miles away (mainly 20 but I feel a ten mile buffer will help me. FOX is the station I want to get strong) consistently? If I do move it outside and it doesn't perform like I want it to, is the Antennas Direct DB4E a good antenna? This is kind of what my DIY is modeled after.

Second question: How do I properly ground my mast? I have a grounding clamp here at work. What kind of wire should I use? Is 10 AWG good? Should I run it down the fascia and right into the ground? Does placing the ground clamp above the antenna automatically divert any lightning away from the antenna?

Thanks for the help.
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Old 25-Jul-2013, 1:12 PM   #2
Wake49
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Well, my mount came in yesterday, and I have picked Saturday as my install day. I have to work in the morning, so weather pending I should be able to watch some Saturday night TV...

What I have learned from some research and internet chatter is that I have to ground both the mast and the coaxial cable. I will be doing this with a mast clamp with a #10 AWG wire running to a grounding rod (HD only sells an 8', I don't need to bury that much, right?) and interupting the coaxial cable before it enters the house with a grounding block that I will also run with #10 AWG wire to the grounding rod.

Is there anything I am missing?
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Old 25-Jul-2013, 3:04 PM   #3
elmo
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I'll leave the grounding to those who know that subject well. It's not really too hard to do, but if not done right, you could be in for a shock.

So anyway, the 751 is a fine antenna for gathering channels from a range of directions. And since you have it, mount it and see how it does. The 20 miles isn't an issue for it. Now that you're on the roof, it should perform better. I'd start at 47 degrees by the compass, then tweak as needed. Keeping it pointed away from ABC since that's so strong, will help tune that down a bit, which can be a good thing sometimes. And if it doesn't work out, you can always go for a DB4E as it is a good antenna too. It's not VHF tuned but with ABC virtually next door, it'll tune it as you've seen by your DIY. So if you're more inclined to go that route, I don't see an issue. The reflector grid should help to boost reception. The gain profile seems to increase as does the real Ch # increases, according the the tech specs on it.

Of course, avoid all the trees and buildings and runways that you can.

Good luck and keep us posted.
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Old 26-Jul-2013, 2:37 PM   #4
Wake49
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Ok, thanks elmo.

I think I have the basics of grounding down. I am just curious on grounding the rod I am burying behind the house.

From everything I have read, it seems that I am supposed to ground the rod I am burying at the back of the house to the service box in the front of the house. Can I ground it to the grounding rod in the front that is attached to the service? This way I can run a wire around the perimeter of the house and don't have to run it through to access the panel. Otherwise, the panel is easily accessible...
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Old 26-Jul-2013, 4:32 PM   #5
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Post # 20 of the thread, http://forum.tvfool.com/showthread.php?t=901 summarizes the basic steps of grounding the mast and coax.

If you need to add a ground rod, be sure that the antenna ground system is bonded to the existing ground system that serves your electrical service. Bonding provides a reliable connection between the two parts of the grounding system, so that they will not have large voltage differences if there is a fault.


I own a DB4e, its an excellent UHF antenna. Try what you already own first.
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Old 26-Jul-2013, 8:44 PM   #6
Wake49
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One thing, I am locating the antenna on the back of the house, and my service is on the front of the house. How do I tie the two together? Should I run a #10 wire around the house at the foundation to tie the two ground rods together?

Last edited by Wake49; 26-Jul-2013 at 8:50 PM.
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Old 26-Jul-2013, 10:40 PM   #7
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If you opt to add a ground rod, you'll need to use #6 AWG or heavier copper to bond (tie) the grounds rods together. This is to provide for the possible current that could occur during a fault other than just the antenna system... the new rod becomes a part of your power system ground.

An alternative is to run the mast ground to the existing ground rod using #10 AWG. Then, run the coax to a point close to the existing ground (10' or less as the wire runs) where you would locate the grounding block. This option avoids the cost of a new ground rod and a long run of #6.
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Old 27-Jul-2013, 3:41 AM   #8
Wake49
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So, from that thread I read one of those manuals and saw this picture:

house.jpg

This is an exact picture of my situation. I cannot mount the antenna on the front of the house due to power lines in the way, so I have to mount it on the back. This creates the problem of there being no direct route for the 10 AWG wire to run to the grounding rod in front. I would have to run it around the house and then I have to worry about bends and frays and other hazards associated with that type of long-run installation. What they have pictured here seems to be the best option for this particular situation. Believe me, I don't want to spend the extra money on a roll of #6 AWG wire, but I don't think there is a safe way to do it otherwise. I also think the best option is to run the #6 AWG wire through the house like they show here. Should I run it through Scheduled 40 conduit? Would that insulate it in case of a strike? And I can connect that #6 AG wire to the ground wire in the box (like is shown in the picture), correct? I don't want to run it inside and then out again.

Thanks again for all your advice. I appreciate it.
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Old 27-Jul-2013, 4:16 AM   #9
GroundUrMast
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Despite the suggestion made by the nice drawing, I would avoid running an antenna system ground conductor into or through a building. In the unlikely event of a direct lighting strike or major power system fault, it seems prudent to at least try to keep the energy outside the building.

The option of running a #10 or better mast ground direct to the existing electrical service ground and avoiding the expense of a new rod and #6 copper looks like the best choice to me.
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Old 27-Jul-2013, 2:15 PM   #10
Wake49
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Quote:
Originally Posted by GroundUrMast View Post
The option of running a #10 or better mast ground direct to the existing electrical service ground and avoiding the expense of a new rod and #6 copper looks like the best choice to me.

Ok, I will do it this way.

I am going to run a 1/2" conduit around the perimeter and am running a home run from the mast to the existing service with #10 AWG wire. I am putting the grounding block right where the coaxial is entering the house, which is directly below the antenna. I will then continue the ground (this will not be spliced. I will just bare the wire at the grounding block) around the house to the front where the service is. I can just tie my #10 AWG wire directly into the existing ground rod (with the appropriate connector) and I am done?
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Old 27-Jul-2013, 4:56 PM   #11
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New info... new suggestion

Given that the coax enters the house on the opposite end from the electrical service, you may well find it best to add a new ground rod near the coax entrance point. Bond the new rod to the existing ground rod with #6, then it is a part of your electrical service ground. That allows you to keep the mast ground isolated from the coax ground until they meet at the electrical service ground connection.

If the coax ground block is more than 10' (wire length) from the connection to the electrical service ground, you have the possibility that a large fault current would cause a large voltage to appear on the coax due to the voltage drop in the long grounding wire (between the grounding block and electrical service connection point). The situation is worse if the mast is hit, and the ground block is sharing the same ground wire.

The mast ground should not serve the coax ground block. The coax ground block should be located close to the electrical service ground and use it's own short length of #10 wire to connect the the electrical service ground.

If you want to put it in conduit, that's your choice.
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If the well is dry and you don't see rain on the horizon, you'll need to dig the hole deeper. (If the antenna can't get the job done, an amp won't fix it.)

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Old 5-Aug-2013, 7:36 PM   #12
Wake49
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Ok, I finally finished moving the antenna above the roofline via a gable mount.

My configuration:

Coaxial: Antenna's transformer to a RCA Preamp, Preamp to grounding block, grounding block to preamp power supply, power supply to TV. Coaxial grounding block is grounded to grounding rod with its own #8 wire.

Mast: Home run #8 wire from grounding clamp on mast to grounding clamp on rod on rear of house.

Grounding rod: Added at back of house to accommodate antenna service, bonded with # 6 AWG wire around perimeter of house to the main service grounding rod, tied each with its own grounding clamp.


I am now picking up FOX and CBS reliably, most of the time with six to seven bars of service. I did lose reliability for real 20 (WCCT) and real 39 (WCTX). I am surprised with real 39, since it shares a tower with WTNH 8 and I get that with seven bars no problem...

I rarely watch those two channels, and I think that I am happy with my lineup now that I get FOX and CBS (although after all this hard work I read that those two are threatening pulling their OTA broadcasts). If I feel really necessary though, I might just end up buying the DB4E antenna, as I know that it will outperform my RCA ANT751R. But I am happy at the present moment with what I have.

Thanks!
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