After a lot of self-debating, tossing and turning things over and over in my mind, I continued ahead with my plans to rebuild my ham radio tower setup,
as described here two weeks ago. Today, a helper and I dug a 2'x2'x3' deep hole, built a rebar cage, coated the aluminum pipe with a heavy sealant and put it up. The rest of my parts for the job are here, but no more work will be done for a while. Concrete used in critical places (self-suspending balconies, for example) has to cure for 28 days before the forms are taken off, so I'll leave this sit with no stresses on it for those 4 weeks. Or thereabouts.
There was a long discussion in the comments back then about just using a 4" PVC pipe filled with concrete instead of aluminum pipe. In the end, I went with this pipe for a few reasons. Most importantly, I'm not experienced enough with the PVC approach to feel sure that it would hold up, and I wasn't able to get enough information to convince me. Since I'd already bought this aluminum pipe, and was familiar with everything I'd done to get to this point, I decided to go with what I had. As a bonus, if I wanted to go to a bigger tower or heavier load, I feel confident this is capable of handling it, while with the PVC pipe approach, I'd be less sure I could do that.
Before you ask, there's a plastic plug in both ends of this pipe so that it can't fill with water.
My plan for now is that once the pad is cured sufficiently, I'll mount all the hardware I bought to replace the winch and cable, and then crank the tower over. Once that's down, I can do a bit of routine antenna maintenance, like check the cables and connectors. I'll get a good look at the house bracket and see if it needs anything beyond the bit of scraping and repainting I can see now. I should be done by the end of March.
For the next few weeks, though, this job will mostly just sit. There's indoor work to be done getting the hardware ready to mount, and I'll be spending more time on my CNC conversion project.
Cool......
ReplyDeleteMeanwhile, I'm still in the garage sorting out stuff and trying desperately to make enough room to get the Supra (BACK!) in there......
Looking at the photo, if you run a guy wire from the top of the aluminum pipe down to the left and attach a ground anchor set into concrete some of the bending stress would be transferred to the ground anchor.
ReplyDeleteThe guy wire would not have to be attached until you were raising/lowering the tower and the guy wire and connectors could be stored away from the elements.
The angles and guy wire cable size have to be calculated.
In rigging, I think it is close to the principle of using shear legs to transfer the strain of a lift.
I worked enough with riggers in the shipyard to learn their job is high skill and they are experts. I also learned enough to know that moving heavy objects is never to be done casually.
Congratulations on a job well done! I hope it works out well for you.
ReplyDeleteThank you for all your help and ideas. I really value that kind of input. In the end I probably went curmudgeon and figured that at least I'm familiar with the approach. By making everything a bit more rugged and rated to a higher working load, I think I have more margin. More in my comfort zone.
DeleteBack when my wife had cancer, we started using the phrase "boring is good". Especially when the alternative to "boring" is "life threatening". In this case, the alternative is a few hundred pounds of metal coming down, and threatening my legs since I'll be standing beside it.