I can't quite get my head around this. Without knowing how much the top end moves, or the middle bows, how can you know the bending moment? If the top does not move at all, and the tower is perfectly
And yet you said just above that the moment would be the same in a pin/pin support. If I had three bathroom scales I'd go do a little experiment, but I don't. So let me ask you what I'd find if I did
BTW, I realize you would need a little more info to give actual numbers - what I'm really interested in is whether all three scales would read the same or not. I would expect them to read the same, i
OK, good. Here's where I'm unclear. Let's say, in addition to the 10 lb load at the top, you put a 10 lb load in the middle of the tripod. What do you see on the scales? Steve K8LX __________________
Tom, I agree with all that, and I think everyone who has been bewildered by the Don't Guy mantra does too. Still, I'm confused by the base moment in Jims calcs and would like to get to the bottom of
Yes of course, but he came up with a number WITHOUT knowing the deflection. That was my whole point. It seems to me that if you hold the top still, and the middle does not bow, then you have pure she
Jim, OK, I thought about that for quite a while (not all day though - I actually worked today!). Went to a couple of web sites that seemed to offer free physics lessons. Drew some diagrams, got a hea
BTW, the page I stared at the longest was this one: http://structsource.com/analysis/types/beam.htm _______________________________________________ See: http://www.mscomputer.com for "Self Supporting
Actually, there's a lot of cushion provided by a long mast. I had an extended guyed 72' HDBX style tower in the 60s, with the rotator a couple feet off the ground, rotating a 4 el tri-band quad throu
No. Commscope cable is smooth, while Andrew is corrugated. Completely different animals. As a matter of fact, there was a change in Commscope 50 ohm product a while back, which means there is two se
Those interested in seeing in what cameras are commonly available would do well to download the catalog at: http://www.atvresearch.com/ ATVResearch is wholesale only but I notice that they seem to ha
Interesting. I've been buying TV headend equipment from Mel for at least 20 years. I wondered about the "ATV", but it seemed that they were mainly headend gear at first, then gradually started carryi
Without having used the specific connectors you mention, I'm going to guess that you are trying to use standard "F" connector technique. The "other" technique is probably the one you need to use with
Not exactly Phil - the stiffness of the guy has a significant effect on the accuracy of a deflection type gauge. For a given tension, a flexible guy (i.e. aircraft cable) will deflect the gauge less
Pre-tension is so named because it's the tension in a guy with no wind present (pre-wind, I guess). I like "initial tension" better. Obviously, the exact amount of pre-tension is less important on a
Right, it's a measure of the force required to bend a wire under a particular tension. So there are two components of the 'resistance': that caused by the tension, and that caused by the wire stiffne
Sure. Assuming a 100' tower, attach a c. 60' cable to the tower at the 100' level AND the 50' level. Grab the center of the 60' line with the crane hook. As the tower goes vertical, the crane hook sl
The advantage is that at the critical beginning of the lift, you have lift at the middle of the tower, and at the end of the lift, you are holding the tower at the top, so it hangs mostly vertical. W
Sure - see: http://www.anchorguard.com Though it seems like for small towers it would be simpler to just add an insulator in each guy wire. 73, Steve K8LX ____________________________________________
Hi Stan, I once tried that very thing with 70' of 1.5" schedule 40 pipe, and was amazed at how much twist there was in that length of pipe. My antenna was a 4 el triband quad on a 30' boom. In strong