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## Re: [TowerTalk] Tram rope

 To: Re: [TowerTalk] Tram rope "David Robbins K1TTT" k1ttt@arrl.net Mon, 18 Dec 2006 21:21:13 -0000
 It depends on the angle of the dangle, so to speak. The the copy of the YCCC Scuttlebutt article at the top of the page at: http://www.k1ttt.net/technote/tram.html for calculating forces. In the examples I show that a 100# antenna can easily get over 500# tension on the rope if you try to pull it too far out from the tower. David Robbins K1TTT e-mail: mailto:k1ttt@arrl.net web: http://www.k1ttt.net AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net > -----Original Message----- > From: towertalk-bounces@contesting.com [mailto:towertalk- > bounces@contesting.com] On Behalf Of Dick Green WC1M > Sent: Monday, December 18, 2006 18:57 > To: 'Dennis OConnor'; towertalk@contesting.com > Subject: Re: [TowerTalk] Tram rope > > I don't want to be contrarian, but has anyone seen a tram line made of > reasonably strong rope break? Has anyone calculated the actual forces on > the > tram line? For example, the breaking strength of 7/16" nylon rope is about > 4,500 lbs, with a safe working load between 450 lbs and 900 lbs (some > references say no more that 1/5 breaking strength, others say no more than > 1/10 breaking strength.) Would the forces exerted by a 100 lb antenna on a > tensioned tram line exceed that? Also, the haul rope supports some of the > weight of the antenna. Doesn't that figure into the equation as well? > > I ask this question because yesterday I successfully trammed a 44 lb > Cushcraft 40-2CD to 110 feet using 7/16" 3-strand nylon rope. The next > antenna to be trammed is an 81 lb SteppIR. Is there really a chance that > my > tram line will break? > > 73, Dick WC1M > > > -----Original Message----- > > From: Dennis OConnor [mailto:ad4hk2004@yahoo.com] > > Sent: Monday, December 18, 2006 7:27 AM > > To: towertalk@contesting.com > > Subject: [TowerTalk] Tram rope > > > > Let me second Dave's comment... Using rope for a tram line, > > or small diameter cable is asking for a crash... I also use > > only 1/4" EHS... Because the tram line is pulled into a > > caternary shape the total forces on it are far greater than > > just the weight of the beam... > > The other thing I do is that the tram line is run up to the > > top of the tower, through a pulley, and back down to a ground > > anchor on the opposite side... This way the side thrust is > > not transferred to the tower... Because of having to fly the > > beam over the woods, etc., my tram line is 600 feet overall > > and is kept on a drum and used only for that purpose..... > > > > denny / k8do > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam protection > > around http://mail.yahoo.com > > > > _______________________________________________ > > > > _______________________________________________ > TowerTalk mailing list > TowerTalk@contesting.com > http://lists.contesting.com/mailman/listinfo/towertalk _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk
 Current Thread [TowerTalk] Tram rope, Dennis OConnor Re: [TowerTalk] Tram rope, Dick Green WC1M 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