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## Re: [TowerTalk] Guying a self-supporter

 To: Steve Maki Re: [TowerTalk] Guying a self-supporter "Roger (K8RI)" Mon, 10 Nov 2008 01:12:53 -0500 mailto:towertalk@contesting.com>
 ```Steve Maki wrote: > Roger (K8RI) wrote: > > >> Static load would increase on all legs. I'd expect to see the down wind >> leg loading increase to a point, depending on guy tension. >> > > Roger, > > I want to understand exactly what you're saying here. > > In a strong wind, would you expect there to be more total compression in > the downwind leg with guys attached? I would expect just the opposite... > Not at all and I hope I can put this into proper words. What I'd expect in in a static, no wind condition would be more compression just from the vector sum of the guy tension IE sum of the total COS angle of the guys with the tower multiplied by the tension. What I'd expect in any specific wind would be less percentage of the *total* compression on the down down wind leg "at the base" with one caveat. With guys not tensioned strongly enough I would expect the compression to behave much like an unguyed tower up to a point where the guys would stop the bending of the tower. The guys are going to have some effect even at very little tension. IOW the tension would increase on the down wind leg *until* that point was reached and then the % of the total compression would become less on the down wind leg. In the case of guying at a single level below the antennas with proper guy tension I would expect the % of the total compression to be reduced on the down wind leg "at the base", *but* at the guy point I would expect the bending moment to cause a considerable increase in compression just below the guys. IOW the load above the guy point would act as a lever. AS a relatively extreme example, If the antenna was 10' above the guy point and and was producing a force of 20# it would produce a bending moment at the guys of 10' X 20#, or 200 ft pounds where normally that skinny section of the tower would see very little compression force. More typically the guys would be much closer to the antenna producing far less leverage and bending moment at the guys. In the example, if the tower were strong enough (which this one in the example isn't) a second set of guys would be some where about 10' below the first set or about the same distance below and the load is above. (It's not quite that simple, but it's close with straight tower sections of the same strength) > In low winds, yes the static compression from the guys will add moderate > extra loading, but I would expect the curves to cross at some medium > wind speed. Agreed. > This is for a rigid tapered tower (which doesn't exist), but > I'm betting the results are similar in most reasonable real life scenarios. > > Probably so. I used the BX series as they are relatively inexpensive and would present an extreme example due to their characteristics. IE, that top that's like a wet noodle. <:-)) The HDBX is much stronger, but doesn't go as high and the sections are much heavier. Roger (K8RI) > Steve K8LX > > _______________________________________________ > > > > _______________________________________________ > 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 Re: [TowerTalk] Guying a self-supporter, (continued) Re: [TowerTalk] Guying a self-supporter, jimlux Re: [TowerTalk] Guying a self-supporter, Steve Maki Re: [TowerTalk] Guying a self-supporter, jimlux Re: [TowerTalk] Guying a self-supporter, Steve Maki Re: [TowerTalk] Guying a self-supporter, Roger (K8RI) Re: [TowerTalk] Guying a self-supporter, Steve Maki Re: [TowerTalk] Guying a self-supporter, Peter Voelpel Re: [TowerTalk] Guying a self-supporter, Steve Maki Re: [TowerTalk] Guying a self-supporter, W2RU - Bud Hippisley Re: [TowerTalk] Guying a self-supporter, Bill Re: [TowerTalk] Guying a self-supporter, Roger (K8RI) <=