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| 20m dipole that was taken down |
Well before I left for Europe I was contemplating another antenna for my attic. At this point I have a 20m dipole, a 40m dipole made from two mobile whips as well as the same for 30m. It is getting very crowed up there. It would be nice to replace them all with one antenna. I did try using my High Sierra Sidekick but the results were very poor to say the least. So that came down and on once again on went my thinking cap. I some how stumbled across the Alpha Delta DX-EE. It's only 40 feet in length, covers 10,15,20 and 40 meters with the tuner in my K3 I can also get 12, 17 and 30 meters. With this antenna I could remove the other antennas to make room for 6m's, put my Discone antenna back up and possibly an active antenna. This past
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| 40m dipole still up for now |
Saturday I assembled the antenna, it is made from 12 gauge solid wire which makes it very easy to work with. I had to do the assembly in the basement as the antenna is 40 feet in total length. I got Julie to help me get it up into the attic. From there is was bumping my head, crawling around on all fours and weaving between the rafters. Each leg is in a "Z" configuration as the attic is not 40 feet in length. Most of Saturday was spent assembling the antenna and getting it into the attic. Sunday was spent getting the SWR readings and fine tweaking the antenna. Below are the SWR readings before adjustments.
40 meters
7.000=5.7 7.030 = 6.1 7.060= 10.7 (lowest SWR @ 6.788 1.5)
20 meters
14.000= 1.97 14.030= 1.9 14.060= 1.9 (lowest SWR @ 14.551 1.)
15 meters
21.000= 1.7 21.030= 2.0 21.060= 2.3 (lowest SWR @ 20.730 1.1)
10 meters
28.000= 2.2 28.030= 2.2 28.060= 2.4 (lowest SWR @ 27.711 1.1)
So now its time to tweak the SWR which was made very easy ( except for the up and down from the attic) with my MFJ antenna analyzer. Below are the final results I was able to achieve, now having said that I did have a slightly better result but I got greedy and wanted to further improve on what was a very good over all SWR. In doing so I ended up never getting it back to that sweet spot......so lesson learned "when the SWR is what you think to be the best LEAVE IT ALONE"
Final SWR readings
7.000= 2.52 7.030= 1.60 7.060= 1.59
14.000= 1.88 14.030= 1.98 14.060= 2.0
21.000= 1.39 21.030= 1.46 21.060= 1.54
28.000= 1.4 28.030= 1.61 28.060= 1.76
So over the weekend I am going to do some tests between the new Alpha Delta antenna and the only remaining antenna in the attic my 40 meter mobile whip dipole antenna. I will post them when the results are in.