This a a mast guy bearing for the Buddypole amateur radio portable antenna system using AirSoft BB's as bearing's.
I love taking my Buddipole into the field and enjoying "portable" radio operation. But, I get frustrated when I try to change the heading of my dipole or beam antenna because the supplied guying system gets tangled when I turn the mast.
This design solves that problem while providing a very secure method of attaching the guy wires to the antenna mast. I set the guy lines before assembling the antenna parts. Having the guys set first makes it less likely that the mast will fall while raising the antenna.
To use the bearing:
- Put the mast in the tripod and raise the top mast section 10-20 cm (~ 4-8 inches).
- Snap on the bushing halves with the wide portion at the bottom. (see pictures)
- Slide the bearing onto the bushing with the wide part at the bottom.
- Make a knotted loop ~30cm long in a bearing line and pass from the bottom to the top of one of the eyelets. Then pass the loop of line over the top of the antenna and around the bearing. Pull taught.
- Repeat step 4 with the other 2 lines.
- Raise the top mast section all the way and pull the bushing and bearing down to the bottom of this mast section so that it sets on the lower fitting.
- Now raise the antenna mast all the way and set the guy lines and anchors.
- Lower the mast and install your antenna
WARNING: Do not tie (or clip) the guy lines to the eyelets. They are not strong enough to stand the force and will break in a stiff wind. The magic of this design is that the guy lines wrap all the way around the mast for strength.
If you don't want to build this yourself, it is (or will be soon) available for sale at: http://stores.ebay.com/N0WL-Radio
Use strong plastic for this design. I prefer PET-G.
I also like to use high-visibility colors so the small parts are harder to lose in tall grass. Stealth applications might require camouflage colors or black...
You will need the following for final assembly
- 40 Airsoft BB's
- Lubricant (silicon grease from the plumbing section of your hardware store - or - TFPE lubricant)
- An electric drill
There is a notch on the outer ring of the bearing that allows you to insert the BB's. They are easy at first, but by the time the bearing ring is full, they are quite difficult to insert. I use the flat side of a plyer to press them in. Remember to insert bearings from both sides. Lightly greasing the bearing walls with silicon grease makes the assembly a little easier. If you don't use silicon grease during assembly, be sure to lubricate the bearings afterwards.
I use a drill to break in the bearings. Press the bearing against the drill chuck and let it spin at full speed for 30-60 seconds. The flip the bearing over and repeat.
There are holes through each bushing half that can be used to attach the halves together with a cord. It make it harder to loose a half of the bushing.
This was designed in OpenSCAD. I am publishing the source here. This should work for any mast bearing. Just modify the mast parameters at the top of the source to adapt it.
The bearing design was inspired by http://www.thingiverse.com/thing:2098928, especially the notch to insert the BB's; although my code is 100% original. Thank you "EasilyBuild" for publishing your original design.