Plenty beefy, more than adequate! I usually use a piece of 2x8 or 2X10 on the underside of the decking if I can't hit a rafter or truss with the lag screw.

Don't forget to use sealant on the external holes. Pitch pads are best (we now include them in new production J-mounts) followed by roof-grade silicone.

tmp31416, Other than the fact that I don't like using J-mounts for large antennas, it looks good to me.

I would be careful drilling outwards. If you aren't perfectly straight, the spacing will be off on the outside. You may want to only drill only one hole from the inside and then do the others from the outside with the foot as a guide.

Instead of guide holes ... why not just measure from the peak down to the top of the boards? You know the width of the boards you added so you can easily figure where the "backer boards" lies. If this site is near a roof vent (or something else) then you can use that as a further "landmark" in helping you in locating it's position.

Does a homes steel roof effect reception on a ota?Also wondering would it help reception if you ran a wire from my small outdoor antenna to the steel roof.Thanks in advance for your comments.....bart53

As long as the antenna is well above the peak of the roof, by at least several feet, it should have minimal impact. The father above, the less impact there will be. Placing the antenna near or below the roof will reduce reception significantly, even of local channels. An attic antenna would be next to useless. Another side effect could be multipath reflections which could cause ATSC reception issues.

Running a wire from the antenna to the roof?! :confused: Not sure what this will do but cause signal degradation or cause static discharge through the RG6. You might want to consider grounding the roof with grounding rods and installing lightning rods to prevent static buildup.

The metal roof will not make a good antenna, if that's what you meant by running a wire to it. :)

Further to comments above: You also don't want to use an attic install antenna with a steel roof.

Does a homes steel roof effect reception on a ota?Also wondering would it help reception if you ran a wire from my small outdoor antenna to the steel roof.Thanks in advance for your comments.....bart53
Use steel roof as antenna - Bad idea.
Use attic antenna from inside steel roof - Bad Idea.
Use antenna below roofline pointed through steel roof - Bad idea.

Use antenna below roofline pointed away from steel roof - No problem
Use antenna above roofline pointed in any direction - No problem

the same as it was in june 2009

http://digitalhome.ca/forum/showpost.php?p=947890&postcount=930
http://digitalhome.ca/forum/showpost.php?p=947936&postcount=931
http://digitalhome.ca/forum/showpost.php?p=947946&postcount=932

Folks, just a reminder that if you lose track of any of your earlier posts here at this site it is very easy to find them: see Post #25 in the OTA FAQ for how to do that.

We rely on the good will of everyone here, so we've made it easy to get the OTA info you need that has already been provided so generously by our veteran and experienced members.

cheers

Thank you all for your replies to my questions.They all have been answered fully....bart53

[Not sure if this Reception Results forum is the right place for this (other than I do live in this area). I looked for a more appropriate location, such as an Installation forum, but, alas, didn't find it. However, if there is another place, mods please don't hesitate to move this post to that forum -- thanks.]


Has anyone put up a strap-type chimney mount on a chimney structure that is wood frame and paneling covered by aluminum siding, with square columns at the corners.

I'd like to get my CM4228 up permanently, and a bit higher, than it is now. I also want to avoid punching holes in the roof or siding.

I'm considering a chimney mount (strap-type) such as the CM 9067 ( http://www.channelmasterstore.com/TV_Antenna_Chimney_Mount_p/cm-9067.htm), which has the longer straps that would be necessary to reach around the structure. It would also allow me to use a 10 foot pole, with the straps set about 5 feet apart, thereby minimizing the stress. There would be about 4-1/2 feet of pole above the chimney structure so that the 4228 could still have a reasonable margin above the aluminum.

My main concern is whether the siding, and particularly the corners, can withstand the strap tension without collapsing.

I have tried pressing hard against the corners and they seem quite solid, although where they reach near the ground, some have been dented, e.g., by my lawn mower coming too close!

To deal with this, my thought is to use 1-1/2 inch aluminum angle (or something similar) that's, say, 3/32-inch thick, along the vertical corners extending above and below the straps, as reinforcement.

I think this would reduce the risk of collapsing the corners by spreading the tension more along the full distance from above the upper strap to below the lower strap. But this is only my "theory" and I'm not sure if this will really work as well as I think it might.

Here's a photo of a similar chimney structure with the corners and antenna mounting hardware "added" (my rough editing).

http://i1008.photobucket.com/albums/af209/plainom2/chimneybwSmall.jpg

Any comments, ideas, suggestions or experience with this type of installation?

The siding corners will not take the compression of straps. The corner pieces have no real structural strength to them. They will bend and/or crack. Plus it will look ugly.

Why not use a few lag screws right through the siding? Bell TV installers do it all the time for dishes. You can caulk around the holes, and fill the holes at a later date with caulk should you ever remove the antenna mount.

Agreed with MaxHeadroom. Further, Lag bolts are probably a cheaper approach than using a chimney kit.

This will also work best if you can get the lag bolts into the frame.

You can't use aluminum siding for structural integrity.

Note that using a chimney kit would--due to the compression issue--make leveling the antenna next to impossible (in addition to the nasty aesthetics of bending/warping the siding). And likely create water ingress behind siding, etc. Problems that will cost way more to fix down the road....

MaxHeadroom, Jase88:

Thanks for the responses. You've addressed my concerns.

I can only speculate as to where the framing is underneath, and that's part of the problem.

The framing is clad with a paneling material that itself cannot support a load so I have to get to the framing. I would imagine that the corners are at least two 2X4s at 90 degrees, so there should be a couple of inches of access at those points and there's probably some vertical studs at 16 or 24 inch spacings. It would perhaps allow for a J-pole type mount, but I have to get the CM 4228 8-bay a fair distance above the chimney exhausts, and I wonder if a J-pole type mount will be able to support it (especially under winter ice/snow load). [E.g. the Winegard DS3000 with an extended pole.]

I wonder what the Bell/dish installers do to find the studs in behind. Also, do they put the mount directly on the siding, or do they use something to shim it so that the siding isn't crushed?

In addition, If it's on a J-pole type mount on the side of the chimney structure, there won't be any way to reach the antenna itself -- it would have to mounted on the pipe, and then the pipe raised, pivoting at the mount. This would be problematic for fine adjustment of the direction.

Dish antennas seem to be placed on the side of the structure more-or-less directed toward the signal source, but in my case, I'm interested in signals on both the front and back of the antenna, so it has to be up in the clear, and not have the house or chimney siding behind it.

That's where the chimney mount with a 10 ft pole seemed to do the trick. Because the pipe clamps on the mounts would be within reach, it would be possible to loosen them to turn the pole for aiming, and to remove the clamps to drop the antenna down for maintenance etc.

Okay, so I have to find another way. Perhaps I can do some experimentation to see if I can locate some horizontal framing in the chimney structure, and use wall mounts with a vertical pipe.

Sort of brainstorming ideas to see if something will satisfy what I'd like to have, and work well. (Tall order?)

Why not pull the siding off temporarily so you can start pounding nails through the siding until you find studs? http://www.youtube.com/watch?v=4bh7tHkZBMs

Bell TV installers typically crush the siding under the mount. You can use some blocks of wood to offset to avoid crushing the siding.

I'd forget about a J-pole and use a galvanized fence pole as recommended elsewhere on the forums. Then you can secure the pole at two points on your chimney wall instead of just a single point with a J-pole.

Anyone know if 5 foot tripods are still made by brand name suppliers? All I see are 3 foot ones. BTW, anyone know how far down a mast downs into one of these when the legs are fully opened? Thanks.

Many retailers won't sell the 5' tripods, as they don't include the mast. But yes, they are available.

Jase88, Any suggestions on where to look? Ontario ... GTA. Thanks.

can't find them in ontario, but the skywalker 6030 5ft tripod can be bought online from u.s. suppliers.

If you're a real do-it-yourselfer, I made my own tri-mast.
I have a 12ft pipe on the roof peak, supported by two 8 ft lengths of unistrut.
I used some angle iron lagged into roof joists, bolted supports to angles and attched to mast pipe about 5ft up, with muffler clamps to make it adjustable.
Maybe a little oversized, might have made the roof stronger. :)