| It occurred to me that since the STEP-IR was such a great antenna that it should be possible to copy that basic idea using entirely different materials to create a dipole antenna that could be used on all bands just like their Vertical. |
| If we start with two barrels of PVC connected together for the entire length, we can form an element and a take-up system that would work like a cable and throttle mechanism similar to what controls the speed on your lawnmower. |
| By taping the 2 PVC tubes every foot or so, loose, so as to not choke the movement inside the tubes, we can attach them to support poly rope that will serve as a strain relief, and offer full weight relief for the system. In other words the dipole PVC elements will ride on the mounting ROPE. |
| When the 2 TUBES are mounted, the BRASS element can be easily slid down inside the first tube. When it comes out the far end, a high tensile Twine can be pulled back through to the center drive mechanism. If the length is 140 feet overall, then 140 feet of twine is needed. Once 70 feet of twine is loose at the center and 70 feet is inside the tube, the Brass Element can be passed down the second PVC pipe. The TWINE and the BRASS element are super glued at this far end after being placed over the U-TURN to be described below. |
| When the Antenna is set to it's maximum length of 70 feet on each side, one tube will have 70 feet of Brass Cable, and 70 feet of Twine. When the antenna is made smaller, the Brass will be wound onto the center take-up reel, driven by the Drill Motor. When the Brass is entirely pulled into the center drive, then 140 feet of twine will travel down both tubes. When the motor turns the twine will reverse course at the far end. This is the U-TURN device that accomplishes that. The Brass Element will never go around this bend, just the twine. |
| Here is a layout of a U-TURN made of PVC. The U is a metal device that channels the twine, and is polished to protect the twine from wearing. The end cap has an EYE BOLT installed with heavy washers, and the support Poly Rope is tied to the Eye Bolt. That Eye Bolt will serve as the connection point for support ropes that will suspend the elements |
| When the Brass Conductor is pulled from the center of the antenna, it is moved over a VERY VERY strong Magnet. That magnetizes the element very nicely, and it is conceivable that we could wind up with a 140 foot long MAGNET suspended in space as an HF antenna. I will be curious to note if it improves the performance of the system when it is magnetized? I don't think this has been done before !? |
| N 8 "A" "D" AUTOMATIC DIPOLE |
| RESONANT ON ANY FREQUENCY ALWAYS A 1:1 SWR ON EVERY BAND! |
| FEATURES Cheap to build... The PVC tubing probably costs less than copper wire. Uses a Cordless Drill motor. Any voltage will work, with a supply that will vary speed. PVC Pipe construction for light weight and low cost. I have a few miles of BRASS CABLE -- 22 gauge X 7 -- extremely strong and flexible If you can fabricate simple parts it should be a snap to duplicate. Will work well with a center support like a tower to take the major weight off the system. Magnetized Elements?? Could they be a benefit to reception of RF? Could be used from the ground with ONE element as a Vertical for any frequency. Could be used with many elements as a ground counterpoise. Variable and resonant for any frequency of operation desired. |
| Ideally the center support will be hung from a tower or some other strong support. This EYE will be screwed into the TOP END CAP of the GEAR housing. All weight will be placed on this Eye. The elements will be supported by the POLY Ropes, and suspended by distant supports/trees. |
| COUNTER This is my solution to let you know the length of the elements of your antenna. The Shaft of the Take-Up and Let-Out Reels is the drive, and a gear is threaded onto it. The assembly mounts to the 3 inch diameter Motor Mounting Assembly. As the Drill spins Clockwise or Counterclockwise, the gear spins, and is mated to a larger diameter gear. That Gear in turn, drives a Smaller Gear at it's center, and that smaller gear drives a larger gear. That larger gear has a small gear at it's center which in turn drives an equally sized small gear mounted to a 10 Turn 1K Potentiometer. In my case the use of large and small gears results in a gear reduction ratio of 8:1. As the Drill motor turns the shaft of the Pot is rotated This results in 80 complete rotations of the Reels for a 0 to 1K OHM complete range. At any time a resistance measurement can be made that will correspond to a length of driven element. Power does not need to be applied continuously, and at any time a resistance check can be performed to learn the relative length/position of the antenna elements. It has Memory! This resistance measurement can be applied to a micro-controller for predefined settings of popular frequencies. It can also serve to limit the elements from being driven past the smallest or largest length desired (Motor Stops) |
| Place 3 mounting screws here to LOCK the Drill Motor. |