I think the point to remember is that drill motors are not designed for continuous duty, not even the heavy duty ones. I burned up a brand new, heavy duty Dewalt hammer drill, drilling 3/4" holes in
Jorgensen Steel, now known as EMJ Steel is in Oakland and if not in stock will get whatever you want. They might deliver if headed to your area but otherwise pick it up. Then take it to Pacific Galva
see my earlier post also. I forgot to mention A513 DOM tube which has a little less yield than normalized 4130 with 72kpsi yield at about 40% of the cost. I use it when high yield stuff is needed. Jo
Patrick Please suggest some stocking suppliers and models. Grant KZ1W Ultrasonic emissions have a much higher success record. Ultrasonic waves are easy to "beam" directionally which permits a ground
My 2 cents, having two HDX589s and a TMM433. I don't think you need a thrust bearing, if your tower has the welded in sleeve for a 2" mast. I think this is standard on all the current UST crank-ups.
This could be the result of "value engineering" of the hose clamps by MFJ, so you might consider buying new clamps from McMaster or others that are US made "all stainless". I also found in assembling
Here are some alternatives, depending on the antenna loads, height, vehicle. - used boom truck (maybe <$10k if you shop around) check ebay, craigslist and bidadoo auctions - commercial tower trailer
Plug the element and booms ends with a short piece of open cell foam and cover it with a cap with a small hole on the down side. Water and moisture can escape and bugs can't get in. Not my idea, done
Today, I took down a A4S, original Cushcraft. The 2" x 18' boom was filled with water, probably nearly full. The antenna was way over the spec 37 lb weight. All elements and the boom had end caps. In
"40' could be manhandled"? I want to be far away from that exercise! I'm of the school of slow and safe (particularly when 807's are around), so welded up a 5" channel H about 4' on the cross, 3' on
It been a while since my mechanics course, but I think the accurate way to calculate the loads is to translate the individual antenna wind loads to moments at the tower base. Then sum these and see i
It's an interesting question about the strength of the top section in a crank up, so I looked at the UST calcs for the HDX589, 85mph 3 sec gust, 71mph fastest mile (EIA-222-F). I'm not a PE so this n
A very cool finite element analysis! A lot of work to set that analysis up for the LM470. If I see the overload points in your FE analysis correctly, the overloads are in/near the overlapped sections
Hi Dick, What I've learned - Measure the conduit first, I've been surprised by actual pull lengths different than what looked right on paper. I use conduit measuring tape, about 1/4" wide and flat. I
Sand around any conduit/pipe in rocky soil is a good practice. At my WA QTH any holes would let water in even if the conduit was barely covered with dirt. I tried simultaneous pull & glue once and wo
Ground temps are usually lower than where the cables enter the shack and the ground temp swings are larger if there is a real winter at the QTH. So, temp cycling pulls wet air into the conduit and co
"Hermetic" is very difficult to do. Belden withdrew their air dielectric RG8 series coax because of water migration (original 9913 not current 9913F7). I know, I had 270' of it in a conduit. Consider
Lot's of confusion because commercial "thrust" bearings are really some combination of thrust and radial load bearings. What most hams need with tower installations is a bearing for radial loads, som
One of the worst wear environments for a ball bearing is for it to have small oscillatory motions. As in a rotator infrequently used and subject to wind oscillations. This breaks down the oil film an
My PV arrays were on 8" sch 40 pipe buried 8' in 36" diameter concrete (Santa Clara County permit nonsense). A big Bobcat with an hydraulic auger can do that - really amazing. Also, when the auger hi