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netlaw@interaccess.com writes: > I did a "dry-run" assembly of element #1, the 20M reflector--not one rivet > has been pulled yet. Starting with the tip and trying to line up the holes > with the next tube inboard, I can only get one hole of three to line up > sufficiently to accept a rivet; only one of the other two holes is close, but > I can see that it is not quite lined up, and would require drilling. > > Ok, onto the next piece of tubing in the sequence to see if the problem > recurs; there I am able to line up 2 holes. This continues on the A and B > sides for the 20M reflector--at most, I can line up two holes, but around 30% > of the time, can only line up one without further drilling. > > I double-checked the assembly--swagged end for any piece goes inboard, non > swagged goes to outboard side as viewed from boom. All elements I am trying > to assemble are consistently labeled, i.e., 1B goes to another 1B goes to > another 1B, same for 1A. > > The instructions say to put rivets into ALL rivet holes--there is not one > instance on the A or B side of the 20M reflector where I can do this--always, > one of the three holes is not aligned. This also ius visually obvious when > one holds the pieces that go together next to each other; the holes just don' > t all align. When they say "all," are they expecting only two usable holes? Hi, Paula -- Hmm, I haven't run into this before. The elements are assembled at the factory and THEN drilled manually so it's almost impossible to screw it up. Have you tried putting some of the A pieces on the B side to see if they just got swapped? > > I haven't tried the other elements yet. Frankly, I was sufficiently stunned > by this development to figure it was worth investigating before continuing. I > might think the different line-ups for the holes were tuning options, but I > understand that the 20M elements shouldn't require this, and the ability to > align different hole combinations is not consistent (for example, from the B > side, I can sort of align 2 of the 3 holes in the tip piece 2 different ways, > but neither option allows me to fit two rivets in, and of course, each option > involves a different level of telescoping of the pieces). I'm trying to > figure out how they did this at the factory. > I'd try the other elements; I'll bet you a nickel that the others are just fine. The only way the elements could NOT fit is if they got mixed up with other ones that were drilled differently. (They're all drilled differently since each hole is drilled by hand.) Nonetheless go ahead and assemble the element. Put a rivet in one of the holes and do not pull the mandrel out (don't use the riveter); you just want to hold the pieces together temporarily. Now measure it. If it's the right length, rivet it. It doesn't really matter where the holes are - it's the length we're interested in. Hole locations (other than providing some assembly frustration in your case) are immaterial. Feel free to drill new ones if you need to. I've assembled a couple of dozen F12 antennas and they're pretty straightforward - I don't even use the manual - so you just ran into a small speedbump. Let me know if you've got anymore questions. > Suddenly my TH7 doesn't look so bad any more.... That's cuz it's still a high performance tribander. Cheers & GL, Steve K7LXC Tower Tech -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Web sites: http://www.qth.com/force12 and http://www.force12inc.com Submissions: send to Force12Talk@qth.com To unsubscribe: send a blank e-mail to Force12Talk-leave@qth.com Force12Talk Message Archive: http://www.qth.com/force12/list/force12talk For problems with the list, contact n4zr@qth.com |
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