The wind turbine guys do tiltups a lot. (usually just poles though) I did a quick look and found some interesting pics from five 60 meter tall 25g tiltups being used for wind speed instruments (with
yeah I don't know. On the page that had the thumbnails of the pics, they said "25g Tiltup Towers", but may be wrong? see here http://www.hi-techtowers.com/wind_assessment.aspx?stab=projects _________
Is this analysis wrong? http://wiki.contesting.com/index.php/Guyed_tower_study If so, where? It's a 45g analysis. I would think that means 25g sees more deflection at the top. I didn't understand peo
we were talking about tilting up 25g/45g and I mentioned the wind turbine guys. I was just surfing around and found a company that actually sells ginpole kits for tilting up 25g and 45g (this is not
an old issue, well talked about in the archives. But after reading the archives, I thought I could be more specific. Although people named some higher end brands before, I wanted to name some lower e
Hi Dan, I have some fiberglass poles you can have for the price of shipping, just because I have too much crap around the house.. I had a LightningBolt Quad a while back. it didn't last long because
I've bought 3 used towers. (hmm.. actually 4 but I sold one) All involve labor and materials to bring them up to snuff. power wire brushing, pressure wash, phosphoric acid wash before cold galvanizin
my thought was that Kevin might not be "3 1/2 feet into solid rock on all four sides" as it would have been difficult to do that just with a jackhammer. (unless it was soft rock?) What kind of rock i
I guess one could argue the other side of the coin. "You guys are over-engineering all of this. Just drill three 1" holes in the rock and epoxy the rebar or anchor bolts in. No concrete needed" I gue
Question for the people who are sleeping at night: If people create an antenna load that requires such a strong mast to resist bending, then that force is transferred to the top section of a crankup.
"Wind loading specification from the tower manufacturer. In my case, the tower was rated for 23.3 ft2 of antenna located one foot above the topof the tower. This is a 350-lb wind load at that point,
Thanks for the thoughts on analysis. sounds like some folks were interested in this, so here's what I was thinking when I said I wasn't confident analyzing the moment limit at the base was sufficient
Steve: Also: I've never seen anyone describe how to migrate a manufacturers' spec on windload at 1' above the tower, to something distributed across a 10' mast, given moment limits for each section.
I looked at the Equivalent Moment description on page 22-21 of the 20th edition of the ARRL Antenna book. The graphic, Fig 32, shows a uniformly designed 70-foot lattice tower. The section design is
If it's a crankup, I guess there's no guys. Rohn specs 70mph 0.8 sq ft wind area for 60' of unsupported rohn 55g Is that 15 lbs/sq ft? Even if you scale that back to 50mph, how can you get anything a
It doesn't matter whether you analyze the top section as if it started on the ground or on top of something else. It's the same analysis. right?. (except higher wind higher) "about 75 feet of 55G or
I thought I was focusing on the right thing. Worry about the moment once it's up. Design everything around that. I think it's wrong to start thinking about 55g and building out. You want a "thing" th
I thought this was a good read: wire rope failure forensics. Nice photos for a lot of failure modes. From a guy whose career is analyzing wire rope failures. Some nice stuff about lightning issues, p
If the cables don't need replacing at the rate "the field" is replacing them, then why do we get any cable breaks? Are there other issues? Most hams don't do much maintanence, from the cables on used
[Dennis] "From day one, we used an aluminum 2" OD THICK WALL ALUMINUM CONDUIT Mast." I was curious about aluminum conduit. A quick search says that modern aluminum conduit is 6063 temper T-1 (our typ