Posted: 2/7/2012 12:36:45 PM EDT
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I am thinking of putting a mast up for a UHF/VHF vertical (comet GP-1) and TV antenna (whatever cheap yagi I can get local). There seems to be a dearth of information on masts and their use in ham radio, or I'm not looking in the right places.
I see that MFJ carries the Rohn 20-50 foot masts and they will be in my new back yard 
So if I want to put a 20 or 30 foot mast up can I mount it to the side of the gable with a bracket mount and have no need to guy the mast? The gable is at least 14 feet high. If I can't get a 30 foot mast, can I safely push a 40 foot mast up to 30 feet, or will I lose strength? |
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I have the Rohn 40 ft version here. It is extended to 33ft and supports a 40m OCF dipole and a small VHF/UHF omni on top. It is anchored to the soffit at about 10 feet and the base is set in a bucket of stones, buried 1/2 way in the ground. No guys on mine unless you count the dipole. I think you will be fine anchored at 14ft extended to 30ft. I use the cotter pins as well as the clamps to secure the upper two telescoped sections. The bottom section just has the clamp holding it and it has been fine for 5-6 years now.
Masts used with antenna rotators/yagis need to be secured against twisting from the wind. |
| As has been said if you use a rotor it will have to be guyed. I have lost one at 40 foot and a rotor with a large TV antenna. Hope you have plenty of upper body strength. My main complaint is the clamps. Over tightening distorts the tube and males it difficult if you plan on raising and lowering more than a few times. |
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Quoted:
As has been said if you use a rotor it will have to be guyed. I have lost one at 40 foot and a rotor with a large TV antenna. Hope you have plenty of upper body strength. My main complaint is the clamps. Over tightening distorts the tube and males it difficult if you plan on raising and lowering more than a few times. So if I elect to put a rotor on it I need guys...3 I take it? I guess I could still mount my vertical above the tv antenna? However, I'd almost rather turn the thing by hand than set up a rotor and guy it. Especially if I can get away with a gable bracket mount with no rotor Posted Via AR15.Com Mobile |
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Going either way to 30 feet.and anchored at the gable at 14 feet you might be ok. Using the the 40 footer means that you don't extend the last bottom section. Don't do it the other way by doubling the top. It gets top heavy easy.
My fault was misjudging guy anchors and pull out strength. Major straight line wind gist took down top section. Guy anchors were replaced with moble home achiest. Way overkill. I managed to get my hands of four 50 foot HD Rohn. Before they were dropped from the line up. Figure someday I will find a good use for them. |
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Quoted:
I have the Rohn 40 ft version here. It is extended to 33ft and supports a 40m OCF dipole and a small VHF/UHF omni on top. It is anchored to the soffit at about 10 feet and the base is set in a bucket of stones, buried 1/2 way in the ground. No guys on mine unless you count the dipole. I think you will be fine anchored at 14ft extended to 30ft. I use the cotter pins as well as the clamps to secure the upper two telescoped sections. The bottom section just has the clamp holding it and it has been fine for 5-6 years now. Masts used with antenna rotators/yagis need to be secured against twisting from the wind. Yep, a good ground mount makes a lot of difference. Just an FYI to OP, it's actually pretty easy to rotate from the bottom if you need to. A base stub for a "bell" type rotor and a heavy duty pillow block bearing for your eave mount. Poor mans theory of a UST MA series crankup pole. |