Telescoping Masts question

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k1agh

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I'm thinking of getting a Rohn telescoping mast antenna ethier 30 or 40 feet. Anyone use this type? How big is too big? My neighbor doesnt care if I put one up and my town has no issues with it as long as its not an antenna that needs the base in concrete then I need a permit due to land use issues and watershed things. Would 50 feet be too much? I have plenty of space for the guy wires and stakes just dont know how high I want it.
 

N5TWB

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It depends on what you want to put on top of it. A ham friend is going to use one to put up a hex-beam antenna with a small rotor. It will probably be OK because it's a balanced and small wind load. If you're going to put a Yagi, that might be another thing entirely. I assisted in taking down a telescoping Rohn pole with just a dual-band antenna on top and a wire dipole of some sort just below it. Even with guys, it swayed a bunch.

Also, you're going to need some kind of solid base because that's what the guy wires pull the pole down to so you're likely to still need a permit.
 

AK9R

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The Rohn telescoping mast is made of steel. Consequently, it's heavy and it rusts. I think I'd try to find a way to do it with an aluminum mast...well guyed, of course.
 

n5ims

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How high? Simple answer boils down to how much weight do you want to lift while erecting it. They're pretty light duty as far as what they'll support (translates to fairly small antennas, rotors, etc.) but pretty heavy as far as dead weight. Also, guys are a must, and unless you plan very carefully (leave enough slack), this makes the last few inches really really hard to lift and hold into place while you secure it in place. (Too little slack, you can't secure it, too much slack and it'll start to fall over with even a slight breeze.)
 

k1agh

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Well after speaking with another ham who suggested i use a pulley system where the antenna is on a rope and you use the pulley to put it up. He does this with his so he doesnt have to bring the mast down and its easier on maintenance. He suggested a dig a 3 foot hole with gravel on the bottom for drainage and then put a pipe and use quickcrete to hold in place them put the mast in that. I've read other online reviews where people have done that and had no issues. He said the Rohns can hold my vhf/uhf antenna I have and the 160m-10m wire antenna I'm goign to get with no issues. The height I'm still not sure about and I know the Rohns do have a rust issue but is there any other companies out there that make a decent telescoping mast antenna? It will still be guyed and possibility attached to my shed.
 

prcguy

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I've installed dozens of telescoping "push up" masts over the years including many 30ft and 40ft on roofs with large CB antennas for people in the 1970s. These were all whatever brand Radio Shack sold then and they may have been Rohn. I currently have a 20ft version mounted to a deck and handrail with the mounts only 4ft apart, no guys and the mast is nested slightly nested at 15ft and it's had some pretty big antennas on it with no problems.

As a coincidence to the rust comments, about 2mo ago I retrieved a 20ft push up mast I helped install in around 1972-73 and it was buried about 2ft in the ground. The above ground part is in perfect condition and there is rust where the mast was in the dirt but is mostly cosmetic and not a structural problem. That's after about 43yrs sitting in dirt and occasional mud.

If the OP wants to go up 50ft then guy wires will be needed every 10ft and if you hard mount it to the house you don't need guys at the first level. You would need something to keep the mast from sinking into the ground but I don't see any need to bury the base in concrete since the guys will counter any side forces on the base. Its a good idea to provide something for the base to sit on and to immobilize it but you don't have to go overboard, just make sure the base will counter the downward forces of the guys during wind.

Its not fun taking a large push up mast down once its up but when house mounted you can go on the roof and slowly let every thing telescope down to reach your top antenna. You mark where each section was clamped and when telescoping it back up its not bad, even with a 40 or 50ft version. The rope and pulley is the best way to deal with a dipole but the dipole will run into the guy wires when coming down so keep that in mind.
prcguy
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k1agh

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Well I decided to go with a 40 ft mast. It will be attached to a small outbuilding then guyed above it. I was hoping to find a crank up antenna but no luck. Now Im at 216 feet above sea level, will a 40 foot antenna be good foru vhf/uhf and hf?
 
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