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Thanks for the response. Yes, I was definitely giving some thought to bending the ends of the elements. Glad to hear that I'm not crazy and other people have done such things (or are we both crazy?). The system I'm thinking about implementing is one 240N at 120ft and another stacked below it. The lower 240N presents the turning radius problem. I have to put it at around 75ft, just above the second guy level where the turning radius problem exists, or go down to around 48ft below the first guy level to clear guys. I'm worried that 48ft is a bit too low for lower antenna in a 40m stack. Thanks for sharing your experiences. 73, Bob - W3YY ----- Original Message ----- From: "Jim Fisher" <74237.2073@compuserve.com> To: <w3yy@cox.net>; "force 12 reflector" <force12talk@qth.com> Sent: Thursday, May 29, 2003 19:20 Subject: [Force 12 Talk] Magnum 240N Element Droop Bob, At VE1JF we have two C51XRNs, so 4 N-type elements. They perform very well indeed under competitive running and pileup-breaking circumstances. They don't actually droop much, given the nonconductive trusses, but beyond that I wouldn't want to count on their drooping while rotating in winds--they could be flexing up at the wrong moment and cause a disaster. The good news is we also have a 20M reflector on our middle yagi (C31XR-H) which fit the guying system of the previous tower but not quite this one--so per some advice we used a plumber's pipe bender to make bends partway out each side. Seems to work fine, although one could check it more scientifically than we have. One downside is it is the only element of 48 on the tower which has had a rivet failure, due I believe to torquing during end-on winds. The winds around here get up to genuine hurricane velocity, and the bends are maybe 20o halfway out the 20M reflector sides. On the N reflectors, you have plenty of opportunity to bend the ends beyond the linear loading portions and check the tuning with a coax and balun substituting for the shorting wire. I doubt they will be able to hear the difference in VK/ZL or that you will notice any problem with f/b. I would leave the elements long at first and tape the rivets vs. actually pulling them so you can move them to the resonance you want per factory instructions. Speaking of factory, I would ask F12 or F12e for advice on this move. My feeling: go for it! Some pix of our installation on www.ve1jf.com including the QSL page. GL es 73, Jim Message text written by INTERNET:w3yy@cox.net >I'm considering placing a Magnum 240N midway up a guyed tower, but it looks like I might have a problem with the guys not providing enough space for the antenna's turning radius. It's going to be very close, so small things are important. In particular, I'm wondering how far the elements droop at the tip, relative to the boom. If they hang down a foot or two, I may in business. Could anyone provide information on the element droop for this antenna? 73, Bob - W3YY < -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com |
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