how high is high?

[gooey]

Was wondering if someone could give me an idea of how high I could stick my antenna with a chimney mount. I want to get it as high as possible, but without using guy wires.

For some reason I remember reading that the max hieght should be 10' on a chimney mount. I am wondering if I can go 15'

I am just curious what other people have done :whistle:

[tigerbangs]

How high depends on a couple of variables...for one, how high is the chimney? Mine is 12' high, and I had no problem using 3-5' masts: 2 masts below the rotator, and one above it. How large an antenna do you plan to mount on the masting? My rule of thumb is no more than 5' of unsupported masting, meaning 5' above the higher chimney strap. Are you planning to use a rotator? It's not hard to go an extra 5' higher with a rotator, but be very careful of becoming too top-heavy. You don't want a 190" VHF antenna with a Channel Master 4228 mounted on top of that unsupported, or you risk the whole mess landing in your yard.

[coyote]

Understand that a chimney top is not a structural support for anything, it's just a stack of bricks. Now imagine the wind load on your antenna when a storm comes through... with a short mast the chimney will likely be OK. But the leverage of a few 35mph winds on an antenna atop a 15-foot mast WILL, after a few storms, loosen the mortar that holds the chimney together.

How high depends on a couple of variables...for one, how high is the chimney? Mine is 12' high, and I had no problem using 3-5' masts: 2 masts below the rotator, and one above it. How large an antenna do you plan to mount on the masting? My rule of thumb is no more than 5' of unsupported masting, meaning 5' above the higher chimney strap. Are you planning to use a rotator? It's not hard to go an extra 5' higher with a rotator, but be very careful of becoming too top-heavy. You don't want a 190" VHF antenna with a Channel Master 4228 mounted on top of that unsupported, or you risk the whole mess landing in your yard.

[gooey]

Well I have a newer home (about 3+ years old) that does not have a brink chimney. I have a stucco (sp?) chimney.

My current set up is two 5' poles. I think I am going to upgrade it so that I have two 5' poles, attach a CM rotator at the top of this and install another 5' with an antenna at the top of that thing.

The antenna is about 6.5 lbs.

I figure also that this things will only be up for a year or so when D* adds all the HD channels to their local line up at the end of this year.

So anyone think my idea is a bad idea? am I setting myself up for some trouble?

thanks again!

[kevinw]

Possibly. The bands used in the chimney mount have to be pretty tight. Most likely it will crack the stucco. My chimney is plank sided and I had to crank it down pretty tight putting indentations in the wood framing.

Dented wood on a chimney is not a problem but cracked stucco could lead to moisture getting under it. You could try a Tripod mount or even an Eaves mount.

[aerialist]

One of my best configurations is a ten foot tripod with a ten foot inch and a half diameter mast in it. The ten foot mast drops three feet into the tripod leaving seven feet above the tip of the tripod giving you seventeen unguyed feet above the roof peak. A very solid mounting system.