Antennas
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The antennas are probably not spaced far enough apart, but they seem to be working pretty well. In order from the bottom to the top they are an M2 40M3LL, a Force12 WARC-7, a Force12 C-31XR, an M2 6M7JHV and a Diamond X510MA. I currently have a 2 element delta loop array for 80M, from ON4UN's Low Band DXing book (page 12-5 of the 4th edition). I'm not particularly happy with it and will be replacing it with a 2 element vertical array, supported by ropes off the tower, during the summer of 2009. There is an inverted vee for 160M also supported by the tower. My low band receive antenna is a NorthEast only beverage, about 600 feet long. Even though it runs downhill at about a 30 degree angle, it seems to work well. After over 2 years of use, I am reasonably happy with all the antenna choices, except the WARC-7. It works very well on 30M (2 elements, linearly loaded). It is only 2 elements on 17M and that is not adequate. And after I installed it, I discovered that it has a severe pattern distortion on 12M whenever it is close to other antennas. So on 12M, it seems like the beam center is about 45 degrees off of where it is pointed. I think a WARC band antenna with 2 elements on 30M, at least 3 on 17M and at least 4 on 12M, that can work stacked with other antennas, would be an excellent product. All the antennas have held up well through steady winds of 30 MPH, with gusts to 55 MPH. Fortunately, it is relatively dry in Prescott, so there are no signs of corrosion. The mast consists of 2 lengths of 0.25" wall 1026 DOM steel from Array Solutions, one 22' long by 2 7/8" Outside Diameter, the other 12' long by 2 1/2" OD. With help from K6QK and N7TY, I ground the OD of the 12' long mast so that about 2' would slip inside the longer mast. Then it was drilled and welded. The total length is about 31' and about 5' is within the tower. The rotator is a large prop pitch from K7NV, which uses the Green Heron rotor. The rotator has been working flawlessly.
Tower Installation
Our move to Prescott was meant to be for retirement, so I wanted to put up a tower that would handle almost any antenna I could imagine wanting. I was able to obtain a permit from the City of Prescott with the invaluable help of K1VR . If you need help with your permit, I recommend Fred without qualification. I decided on the heavy duty HDX689MDPL from US Tower . My experience with US Tower was generally good. The delivery schedule was a little long (the 689 is usually not an in-stock item) and the shipping scheduling was difficult to manage because I had so many other schedules to coordinate. But the final product is excellent. I ordered the tower and antennas from Tom, KM6K at HRO in San Diego. The tower base specification requires a 6' x 6' x 9' deep footing. The hole had to be blasted from solid rock and in order to be 6' square at the bottom, it is significantly larger at the top. I'm not concerned about the footing going anywhere. This project wouldn't have happened without the help of a lot of people (and the understanding of one special woman). In particular, special thanks to Harv, K6QK (SK) and Bruce, N7TY, who traveled from San Diego twice to help with the installation. Harv's knowledge and mechanical skills really made this possible. A little background - the tower was shipped on an 18 wheel truck, which could not get up the winding road to my driveway. So the crane truck operator unloaded it and placed it on the bed of his truck. This took place in the pouring rain (Harv and Bruce's first trip from San Diego). Since the crane truck was too heavy for the driveway, the plan was to drive up the dirt at the side of the driveway, which of course, was deep mud. So the tower was unloaded at the end of my driveway until things dried out, the crane was available again and Harv and Bruce could make another trip. Now the photos ..... |
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