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(by the way, the 10-15-20M portion really kicks). The MFJ antenna analyzer indicates that we are loading at around 6.800 MHz, so we are way low in the band. The FT1000's SWR meter also indicates a high reading, but since the resonant frequency is out of band, we cannot use the the rig to tell us exactly where we're resonant, except by tuning it to the MFJ's output). We've opened the 3 turn coil about as far as it will go (closing it lowers the resonant frequency), and we've also tried moving the jumpers on the driven element (and only on the side closest to the mast) out around 2" more toward the element tips from the 12" presets. These action have resulted in a noticeable but nominal impact on the resonant frequency. We also have looked closely at the photos in the tech note for assembling/tuning 40M on the C-4XSL, which has led us to pose the following questions: 1. When the alumoweld wire is brought through the center spreader and folded back, should the folded back portion be held by BOTH clamps--that is, by both the clamp that initially holds the end of the alumoweld wire to itself AND the clamp that holds the jumper? Our thought was that by clamping in two places, this would reduce the size of the loop formed by folding back the alumoweld wire, and thereby possibly reduce the electrical length of the element (since we're now clearly too long to be resonant within the 40M band). If this approach is required, I assume this should be done on both the reflector and driver? This is the only thing we could think of in reviewing the photos that seems different from what we've done during assembly, and the comments to the photos seem to suggest the same thing--clamp the folded portion of the alumoweld with both clamps. 2. If the above approach is not required, does anyone have any ideas for why we are loading so low out of band? The leads from the F12 balun are not unusually long (around 3", an adjustment of which shouldn't make a big difference on this band). The antenna is on a crankup that we took to full height to make sure we are clear of interactive items like the roof. We originally assembled the 40M elements to emphasize the CW portion of the band, following the presets in the manual (3" away from the spreader for the reflector, 12" away from the spreader for the driver). Should we be looking to move the jumpers out quite a distance on both elements (even thought that would suggest the SSB preset per the manual)? 3. When making tuning adjustments, do we need to adjust the jumpers at all 4 points of connection to the alumoweld wire, or can we make the adjustments on just the one side of the 40M driven element that is closest to reach (these would be the points of connection that are on either side of the boom, but on the same side of the 40M element)? I know, the manual says adjust them all, but I thought I'd seen some suggestions here earlier that one could make the adjustments on just one side of the element and be OK. Do we need to include the reflector in these adjustments, or just the driver (again, the manual states the driver only, but want to make certain). Thanks. 73, Paula K9IR -------------------------------------------- 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 |