Antenna grounding?

[Scouter]

I have a question about grounding television antennas.

Decades ago we trashed our outdoor antennas in favor of the brand new phenomena of cable TV. Now we are going back (cutting the cord as it's called) and I installed a new digital antenna, a plastic box containing who-knows-what inside.

Right now it's mounted on the chimney with a simple bracket drilled into the chimney. I am still missing a few channels, so I am planning on trying to add a 5' mast that the antenna will sit on, if successful then that is how it will be, otherwise I will go back to the current configuration.

Question: does this type of antenna require grounding? Nothing is mentioned in the installation guide, I've tried reaching out to the company, but turns out they are in China and don't answer emails (wish I had know that before purchasing, thanks Home Depot).

Thoughts?

[R Clark]

We cut the cord six years ago.  We relied on a traditional roof mounted antenna until last fall, when I switched over to an omni-directional antenna installed in the attic.  Works great.

I don't think the roof-mounted antenna was grounded; I didn't see any wires coming from it other than the coax.  I know the new antenna in the attic is not grounded; it only has coax running to it.  I also don't recall any ground wires to house-mounted tv antennae from when I was a kid.

When I installed the new antenna, the instructions recommended going to a web site and inputting our address.  The output from the web site made recommendations about which way to point the antenna for maximum reception.

I put it up in the attic, pointed it in the recommended direction, and it's going fine today.  No ground wire installed.

[Ohio Mike]

Question: does this type of antenna require grounding? Nothing is mentioned in the installation guide, I've tried reaching out to the company, but turns out they are in China and don't answer emails (wish I had know that before purchasing, thanks Home Depot).

Thoughts?

The professional installations I've had done over the years all ran the coax through a grounding block on the outside of the home.  Then they ran a bare copper ground wire from the block to the existing electrical ground rod near the foundation.

[Willyou]

I'm no expert. This is just what I think. Grounding the antenna has nothing to do with reception. It is for the purpose of lightening protection. That would include the mast you are planning for your digital antenna.

[Scouter]

We cut the cord six years ago.  We relied on a traditional roof mounted antenna until last fall, when I switched over to an omni-directional antenna installed in the attic.  Works great.

I don't think the roof-mounted antenna was grounded; I didn't see any wires coming from it other than the coax.  I know the new antenna in the attic is not grounded; it only has coax running to it.  I also don't recall any ground wires to house-mounted tv antennae from when I was a kid.

When I installed the new antenna, the instructions recommended going to a web site and inputting our address.  The output from the web site made recommendations about which way to point the antenna for maximum reception.

I put it up in the attic, pointed it in the recommended direction, and it's going fine today.  No ground wire installed.

Thanks. Do you remember the website? I'm getting some of the stations in the area, but not all of them. Some have just 3 bars, most 5, the 3 bars are too weak to watch.

I've tried it in the attic, not any good. I'm in a hollow, so I need to get it up as high as possible, which is why I'm considering a 5' mast.

[Scouter]

The professional installations I've had done over the years all ran the coax through a grounding block on the outside of the home.  Then they ran a bare copper ground wire from the block to the existing electrical ground rod near the foundation.

My problem with that is the chimney is on the opposite side of the house from the electrical ground. I'd have to run a wire about 75' across a metal roof, pretty sure that wouldn't match any code. If I do need to run a ground, it would have go straight down the house into the actual ground.

[Scouter]

I'm no expert. This is just what I think. Grounding the antenna has nothing to do with reception. It is for the purpose of lightening protection. That would include the mast you are planning for your digital antenna.

I didn't think it would have anything to do with reception, wasn't sure at what point an antenna needs to be grounded for electrical protection. The antenna manual does not talk about grounding it.

[R Clark]

Thanks. Do you remember the website? I'm getting some of the stations in the area, but not all of them. Some have just 3 bars, most 5, the 3 bars are too weak to watch.

I've tried it in the attic, not any good. I'm in a hollow, so I need to get it up as high as possible, which is why I'm considering a 5' mast.

There are a number of different sites.  Don't remember which one I used, but this link will take you to one of them.  Put in your address, and it does the thinking.

OTA Station Finder

The display page isn't the best, so look closely for overlay buttons and getting radials from your address to the stations turned on.

[chrisntam]

I moved mine from the attic to the roof after I installed radiant barrier.  I grounded it, thinking the grounding is only for lightning.  No strikes so far (about 10 years), but if I get a direct strike, I think the antenna will be the least of my worries.

[TDKPE]

Grounding is only for static reduction and lightning “protection” and has nothing to do with reception.  

Www.tvfool.com has the best locator function I know of.  Use the >>Start Maps<<  button on the right side of the screen, put in your zip code, and drag the little icon to your chimney using satellite view.  Set your antenna height to 25 ft.  If you click the “Show lines pointing to each transmitter” button under the map, you’ll see traces to each tower from your location.  

Click the “Make Radar Plot” button at the top-right to generate a radar plot with a more complete listing of stations and signal characteristics.  The higher the noise margin (NM), the better the signal, as it’s a composite of signal strength and the negative effects that can reduce the ability of the receiver to lock on.  Clicking on any station line will give you an elevation with exaggerated ground features that highlight how your signal from that particular tower is shielded and deteriorated, or not (line of sight).

There’s a ton of useful stuff in there.  The radar plot page even includes a URL to your plot, but it hides your actual location so you can post it online without revealing where you are to any but the crudest degree.  Here’s mine - Lat/Lon are truncated to a generic area.  

http://www.tvfool.com/?option=com_wrappe...4d8cf5f38a

What’s most useful about the radar plot is in helping you determine how much antenna gain you really need, what bands you need to receive (high-VHF plus UHF, or just UHF), and if you need more than one antenna with transmitters in different locations, at angles that preclude reception with a single directional antenna (that’s where Omni-directional antennas come in, though they have essentially no gain by definition).

Oh, and there’s no such thing as a “digital antenna”.  If it’s designed for high-VHF and UHF*, it’ll receive what they’re broadcasting, in full high-def glory.  I’m using a 1950’s rabbit ears with UHF loop for my office TV.  That ‘high def’ and/or ‘digital’ antenna stuff is just marketing, and if one does it, they all have to do it or they’ll lose sales.

*There is essentially nothing broadcast on low-VHF (2-6) any more, except I think in Alaska, since longer wavelengths travel further, more or less.  High-VHF (7-12) and a greatly reduced UHF band (now only 14-51, used to go up to 69, and before that up to 83) are what’s used, so antennas are smaller since you don’t need the giant long elements for low-VHF any more.  But each channel still has the same 6 MHz bandwidth - they just impress a different signal onto the carrier than in the analog days.  Sort of like phone lines for voice that were then also used for fax and computer digital information.