: OTA Mounts, Towers, Rigging Hardware
2011-06-09, 05:24 PM
Thanks for the reply HWP. My tower will be freestanding, [no braces] so it really needs to be a heavy duty hinged mount. It's a 68" tower.
Again if anyone has photos or the specs for the HUB 7-8 mount, that would be awesome. ;)
2011-06-09, 06:00 PM
If anyone has any pictures of this hinged mount, can you please post them. Also, does anyone happen to know the diameter of the concrete anchor bolts used?
I've seen the hinged mount for DMX towers--no pictures, though. I believe the rods themselves are either 3/4" or 1" in diameter. Either way, Wade makes excellent towers and equipment, and I trust any design they've put their name on.
As mentioned, this base option is far more expensive. And it's more difficult to level the install vs. the base stub approach.
2011-06-10, 07:40 AM
Thanks for the info.
Given the cost of this hinged base, I was considering making my own. Large concrete anchor L bolts are easily obtained, [Fastenal] and just wanted to be sure I used ones with a large enough diameter. I was considering 1-1/8" or even 1-1/4" just to be on the safe side. Thick walled gavanized pipe is not hard to find either. The last part is the U shaped brackets. I'm still researching those.
2011-06-10, 08:47 AM
You really, REALLY need to be careful in trying to build something yourself. Towers are highly engineered structural devices that have been designed to work with all the matching bits and pieces. Tower failures can cause significant property damage or death.
I personally would only rely on the OE parts.
2011-06-10, 09:16 AM
When speaking with the folks at Wade about the hinged mount, they told me they recently had a failure with the HUB 7-8 mount out west somewhere, during a storm with "extraordinary circumstances". This did not give me a warm and fuzzy feeling about their $800 hinged mount....
When I asked for a drawing or the specs on the mount itself, they would not provide it.
This information and the cost, has me considering making one myself, that is designed well beyond the factory one in strength. Obviously everything would need to be galvanized too.
2011-06-10, 04:07 PM
Here is a picture of the hinged mount. As you can see, it would not be that difficult to make.
2011-06-10, 04:34 PM
300sflyer, the issue is the type of steel used. Different types of steel have different properties (tensile strength, sheer strength, brittleness, etc.). Without knowing that, your home brew attempt will likely end up with your tower on the ground (or on someone's house) after a storm.
2011-06-10, 05:28 PM
I must agree: Unless you're a highly qualified structural engineer, I would not attempt to re-engineer the DMX tower. The DMX product line has been sold since the 70's (or even earlier)--with only minor changes made to the design over that time. It's a well-evolved, tried and tested product.
300sflyer, if the issue is one of heights--ask around here. There are members--like myself--that have successful experience raising a DMX 68' on base stubs. Someone may be willing to help out.
A base-stub installation--in my opinion--is stronger, cheaper and easier.
2011-06-11, 01:40 PM
Yep, agreed 100%! Any damages or losses from a falling antenna tower might not be covered by the homeowner's insurance if an uncertified design is used. A properly engineered solution has certifications (usually an engineer's seal on the design documents) that insurance companies examine in case they are called upon for a payout. Wade absolutely certifies the DMX line provided that it is installed to their spec.
2011-06-12, 12:14 AM
Below is my tower, which I believe is a basic (non DMX) 16 gauger.
As you should be able to see, the main/lower mast does not rise out of the tower much- maybe a foot to two feet. But attached to this mast is a second mast (higher up) that has a CM rotor attached and the stacked antennas which take up all the length of the second mast. If I'm correct, looks like two masts both at 5 foot lengths, not sure of the gauge though.
I'm thinking of replacing the stack with a UHF (91XG) VHF (Antennacraft Y10-7-13) combo and would like to use longer (10 feet?) and stronger masts. (Yes, there is a 4228HD attached to the tower, but I think that is irrelevant.)
Are 1.5" masts stronger than 1.25"?
Can I use 10 foot masts that are 1.5" with this tower and proposed set-up?
If I can use 10 foot masts, how much of the lower mast can safely rise out of the tower and how high can the top mast be raised?
I'm thinking if 10 foot masts are ok, then I could have 5 feet rising out of the tower and 5 feet within/below the tower end. Not sure on how high the second mast can be.
Opinions greatly appreciated.
2011-06-12, 08:04 AM
I use 1/8" thick-walled, 1.5" aluminum pipe for my antenna mast. Very strong and much lighter than steel masting.
I don't know much about the tubular legged towers but if you can mount the rotator within the tower on a plate of some kind and use a thrust bearing on top, you'll be able to put more antennas on the mast. I know the Delhi DMX series has a plate in the top section specifically for this purpose.
2011-06-12, 08:50 AM
I used to have the rotor just above the tower but it would make me nervous to go over an 8' mast on top . Adding in the wind and the weight from the rotor , upper mast and antenna , being offset from the lower mast would put alot of stress on the top of the tower and lower clamp points . I`ve lately mounted the rotor inside the top of the tower and the antennas are mounted on a 10' stainless steel mast . I could go longer with no problem but the 10' suits me fine . I even had room to locate the pre-amp inside just above the rotor . I took a hand grinder to the bottom of the mast for the UHF/VHF cables ( runs inside the mast) to exit. Makes for a nice clean look . I`ve yet to do this for the VHF but she`s coming down to make some hardware changes to the GH10 . I like how sturdy everything is now with the rotor inside the tower . As far as how long of masts that can be used safely , I`ve never toyed with that.
2011-06-12, 10:12 AM
That's great guys, thanks for the info and pics.
I didn't do the tower instal, and when I see other towers around town with the offset method- I'm thinking it's normal. Now I understand why my installer didn't go very high. I'm keen to get the rotor inside the tower with the plate and thrust bearing. Will probably add a little more height if I use the 10 foot mast, and will be better stress wise.
Love OTA: That's basically the set-up I'm aiming for (91XG instead of GH).
2011-06-12, 04:20 PM
Roger, Jase, and Stampeder,
Thanks for your replies. I will certainly consider all of your comments, before I decide whether or not to make a hinged mount. My biggest issue with the OEM hinged mount, is the price tag. For what it is, it just seems WAY overpriced!
I want the ability to raise and lower the tower to make adjustments to the antenna and rotor, without having to climb 70 feet in the air. I don't know of any other way to do, this without a hinged mount.
2011-06-13, 11:05 AM
My intention is not to scare you off, just to help you be aware of some of the non-technical concerns over risk.
2011-06-13, 05:56 PM
I've noticed some farily strong / heavy guage - and very well galvanized / well rust protected - boat dock hardware - hinge and pin assemblies w/various types of pins and hinge assemblies / holes for bolting / mounting etc.
Pretty common in some of the hardware do it yourself stores.
If you can get at least 90 degrees range of motion out of that sort of hinge ... then
It might be possible to modify, and use a few of that sort of hardware as tower hinges at base ?
2011-07-05, 11:31 AM
Question of roof tripods and mounting ...
1. Is there much difference between a "cheap" one vs a brand name one?
2. What should I look for in a tripod?
3. Is it better to get a telescopic mast? If not, what type of pipe should I get as the mast? Is 10ft mast a reasonable size to consider?
4. For better support, I believe tripod legs should be spread to it maximum span. Can you tell me what that spread might be? I'm thinking I will need to strap some additional wood onto the roof rafters to ensure anchors are set into the frame.
5. How best to accomplish that the anchors are in the right place (Question #4). I don't what to randomly put holes into my shingled roof. I know you can fill the holes will roof tar but I rather like the idea of just using the least amount of holes as possible. As the more holes one creates, the better the chance of leaks.
6. Any thing else that I should consider?
Roof is a 2 storey and I don't want to do it more than once.
2011-07-05, 11:52 AM
I've been reading a lot here in preparation for my move from satellite to OTA, and have one concern with my plans. I was going to remove my dish and mount a 4221HD on the same mount, but I noticed that there is an aluminum downspout 2 inches away from the edge of my dish. Will this interfere with the antenna reception?
2011-07-05, 11:59 AM
If it's just the downspout and it's not touching, interference should be minimal. An eaves trough might be a problem. It also depends on the type of antenna.
2011-07-05, 12:14 PM
Just curious... why would an eaves trough be a problem, but probably not a downspout? I ask because I was considering extending my mount to make the antenna as high as possible. This would put it closer to my 2nd storey eaves trough.