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## Re: [TowerTalk] Tram rope

 To: eric@k3na.org Re: [TowerTalk] Tram rope Jim Lux Tue, 19 Dec 2006 16:49:23 -0800
 ```At 12:38 PM 12/19/2006, Eric Scace K3NA wrote: >Hard to draw a diagram on a text-oriented reflector. If you read >this message with a fixed width font it should work reasonably well. > >First, the tram line in this diagram is like the gondola lift you >sited, Jim. Tram wire sits overhead, and the sheave of a pulley rides on it. >The antenna dangles below, and attached to, the frame of the pulley. > >Sketch at the point where the pulley rests on the tram: > ><-- tower is towards the left. > >\ >\ > o._ > | '-._ >(ant) '-._ tram line continues off to right toward ground anchor. > >There are three force vectors meeting at the pulley: > -- antenna weight, points straight down. 100 lb in this example. > -- up toward the tower to the left. I used 45 degrees in my > quickie statics example. > -- to the right down to the ground. I used 30 degrees below horizontal. >If you resolve the last two vectors into vertical and horizontal >components, you can create two equations with two unknowns, and solve. > >Of course, I did the algebra without the benefit of a morning cup of >coffee... and got wrong answers. The answers for a 100 lb antenna should be: > 333 lb up toward the tower > 273 lb down toward the ground anchor That's more what I would think. 700 lbs just seemed a bit too high. Got it... _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread Re: [TowerTalk] Tram rope, (continued) Re: [TowerTalk] Tram rope, David Robbins K1TTT Re: [TowerTalk] Tram rope, Frederick M. Mott Re: [TowerTalk] Tram rope, K8RI on TowerTalk Re: [TowerTalk] Tram rope, Eric Scace K3NA Re: [TowerTalk] Tram rope, K8RI on TowerTalk Re: [TowerTalk] Tram rope, Jim Lux Re: [TowerTalk] Tram rope, Eric Scace K3NA Re: [TowerTalk] Tram rope, Dick Green WC1M Re: [TowerTalk] Tram rope, Eric Scace K3NA Re: [TowerTalk] Tram rope, Dick Green WC1M Re: [TowerTalk] Tram rope, Jim Lux <= Re: [TowerTalk] Tram rope, Dick Green WC1M Re: [TowerTalk] Tram rope, Eric Scace K3NA Re: [TowerTalk] Tram rope, Dick Green WC1M Re: [TowerTalk] Tram rope, Eric Scace K3NA Re: [TowerTalk] Tram rope, Dick Green WC1M Re: [TowerTalk] Tram rope, Eric Scace K3NA Re: [TowerTalk] Tram rope, KC4HW Re: [TowerTalk] Tram rope, K8RI on TowerTalk Re: [TowerTalk] Tram rope, Steve Maki Re: [TowerTalk] Tram rope, Doug Renwick