OTA Mounts, Towers, Rigging Hardware

[ScaryBob]

Assuming flat terrain, the single most important factor with UHF is getting the antenna above local obstacles such as trees and nearby buildings. a 40' tower will typically do that for local and near fringe locations. For deep fringe (over 60 miles) a 60' tower can provide dramatic improvements. However, a lot depends on local terrain. If you are 20' above or below nearby areas, that will subtract or add that distance to the required tower. If possible, get experiences of nearby residents. As mentioned, a site like TVFool can provide information about your general area.

[stampeder]

No such easy to read chart showing a relation between antenna height and reception quality is possible due to the huge number of local variables already mentioned in this thread but also in Post #2 of the OTA FAQ. Generally though, I always repeat what the fighter pilots say: "Altitude = Options" but in the context of this thread I would add "...to a point."

In layman's terms, raising the antenna shows real benefits to a certain point, at which the more time, money, and labour it takes to raise the antenna past that point, the lesser the benefit per dollar/hour/back spasm is achieved. It is the same principle as the law of diminishing returns. For the vast, vast majority of OTA users the point of diminishing returns will never be reached because reception will have already been found to be satisfactory well below that point. Indeed, in some unusual situations reception can be improved by lowering the antenna due to local issues.

As an experiment with the law of diminishing returns, redo your TVFool results in the exact same fashion except increasing your antenna height by an extra 2 feet each time and note that at some point, when the local conditions and relative issues with the path to the transmitter are taken into account, your antenna height's effect on reception becomes almost nil.

[Jase88]

I have the DMX-68 (they measure to the top of your mast, but the physical tower is 64'). In my area it's necessary, as I have plenty of mature trees.

For me, this tower is the very best option. It's free-standing, which allowed me to erect it in the best location on my property--I'm not restricted to the side of my house. It has a rotor plate, which improves the life expectancy of the rotor dramatically. The tower tapers in, which makes installation of the higher sections far easier as they weigh much less. And it's height puts my antenna above most trees.

Installation isn't as costly or difficult as you may think. You dig a hole 4' deep by 46" wide square. Order 3 cubic yards of cement from a local cement company and have it delivered; not all that expensive at all. I have a 4' ground rod which I hammered into the bottom of the hole, then ran a wire and bolted it to the base peg of the tower.

IMO, 20+ feet will make a difference in most installations.

[mlord]

Yes. I should add, if you have the space, then get the highest tower you can afford. No regrets that way, mate!

Cheers

[EMMGEE]

The original poster noted he is Hamilton mountain area. CH, CTS and Sun all broadcast form the east mountain area. Filtering would probably be the best option. WUTV - 14.1 / CH 18.1.

[Steve Gyurki]

First off - My wife won't let me put up a tower. She already does not like the 4 satellite dishes. I want to put up a CM4228 on the chimney. There is a combo antenna strapped to the chimney there now. I have a 5 foot mast then a rotor and another 5 foot mast to the antenna that I want to replace.

My question is - How high can I go above the chimney with the CM antenna safely without adding guy wires?

Thanks for your input.

Steve

[stampeder]

Steve, it depends on the age, size, and strength of the chimney and roof. An aging single chimney can be a hazard when it deteriorates. It depends on the mount type too: a pole bracket lag-bolted into the chimney is only as strong as the brick and mortar itself. A strapping kit distributes the load much better to the whole chimney so that you can go higher. Since you have a double chimney you should be able to do what I did:

At one time I had a 14' pole of 1.5" galvanized steel attached to my double chimney with a strapping kit. It was very stable and served for years with a CM4228 on it. We get gale force winds here on the West Coast once a year or so and it never moved in all that time. I'd comfortably go that high again except I have my doubts about my chimney's mortar as it is getting to be about 35 years old.

First I put down a 1' x 1' piece of 3/8" scrap steel (primed-and-rustproof-painted) to spread the downward load of the pole to prevent it from sinking into the shingles. You could probably make the same sort of base with treated lumber. With the stapping kit I wound the bottom strap about a foot from the roofline and the top one as high as I could get it on the chimney. I presently have an 8' galvanized pole up there with the strapping kit and a pre-4221 Channel Master old timer 4-bay bowtie reflector that gets the Vancouver DTV stations perfectly.

Radio Shack (USA) probably still has strapping kits, and I hear that Princess Auto has them in Canada too.

BTW check with your municipality to see if a chimney mount requires a permit and inspection according to local building codes.

[Steve Gyurki]

I am currently using one of those strapping kits from RS on the chimney. I do not think I am brave enough to go 14' up though like you. I think that I will get a decent gauge 10' X 1.5" piece and cut it for the rotor. My hope ( although faint) is to get CBC-DT from T.O. with a 7777 pre amp thus eliminating the need for StarChoice which is really all we watch on it anymore. May have to stick with analog Kitchener or London. Sadly, it is easier to get Erie, Pa. here than CBC in HD. I guess we may watch Omni now in DT from London also. Anyways, thanks for your time.

Steve

[gohabsgo2]

Steve,

I am getting CBC HD from the CN tower even with my CM422HD just sitting in the upstairs bedroom in south/west Kitchener, near Conestoga college. It is kind of spotty though, especially with bad conditions like the fog we had this morning, it was out. I am sure once I get my antenna up on my roof peak, it will come in much stronger. My location is ~55miles from the tower and the CM4228HD is rated for 60miles. You can check your location at tvfool.com and it will tell you your distance and the Nm (noise margin) rating at your location also for each channel.

Larry

[gohabsgo2]

What do most people use for mast material for a CM4228HD? I plan on using a rotor also - do you just get a pole an cut it and use one piece to hold the rotor and the other piece to go on the turning part of the rotor?

What diameter works best and type of metal and where do you buy it?

Thanks,

Larry

[stampeder]

Larry, most antenna clamps and rotor mounts are for 1.5" O.D. pipe.

Some masts sold out there are just thin walled extruded steel, which don't tend to hold up well in Canada's weather extremes. Your best bet is 1.5" O.D. galvanized conduit pipe. For important info about using galvanized steel see the What materials are recommended for building a mast or mount? section in Post #21 of the OTA FAQ.

[gohabsgo2]

Thanks Stampeder!

[WeeB]

I am planning on putting up a 4221 on an eave mount on the roof of my house. I think I have most things figured out. I am planning on running the coax down the outside of my house and then in through the exterior brick wall and into my living room. I just have a couple questions.

1) What do you most people use to secure the coax/ground lines to an exterior brick wall. Are there any screw in type clips that will screw in and stay secure in the mortar between the bricks?

2) When drilling through the mortar to get in to the house, what is the best way to be sure I wont hit any studs or electrical wires. Also what about the vapor barrier and insulation that is there? Is there any problem with poking a small hole in it to run the coax through?

Thanks for all the help everyone. I have learned so much from this forum and all the great people that are here.

[Tom.F.1]

Hi WeeB,
They sell black cable ties with a screw hole tab on the end. Easier than clips. Lowes has them.
For drilling a hole, measure from a window or door frame inside and out to avoid a stud. i drill straight thru insulation, brick, vapor barrier etc. I use Amazing Goop to fill and seal the hole. Cut the drywall bigger than the hole and fix/glue vapor barrier with a ziplock bag. Install your wallplate over the hole.

[WeeB]

Thanks for the info TomF.1. About the black cable ties with the screw hole, will they just screw right into the mortar? Can you just screw into the mortar just as you would screw into a peice of wood?