My friend Billy doing all the work. The tree has been ignored for several years and the branches of the tree have grown up through the beam.
The completed job. This is a Cushcraft A3 yagi with the 40M dipole attachment. This antenna was first installed on top of this tree in 1984. The A3 has served me faithfully for 24 years but is starting to be intermittent on 40 & 20M. Since I have to take it down for repair anyway, I'm going to replace it. A picture of the new antenna can be seen below. Hopefully, I'll have it up by September.
The wide-angle view. The yagi is 95 feet (29M) off the ground. In the background, you can see the guest house that I have been building for several years now. The exterior is complete and I only have the interior millwork and flooring to finish. I'll post more pictures of it soon.
Here is the antenna stack that I used during the 2008 June VHF Contest. Antennas from top to bottom are: 1) Phased 23 cm 44 el KLM, 2) 70 cm 22 el K1FO, 3) M2 6M7JHV, 4) M2 2M18XXX, and 5) M2 222-10. Just visible at the bottom of the tower is the top section of Roh 25G that is mounted at the peak of my roof. For reference, the 6M yagi is about 45' high.
Above is a picture of one of my antenna projects. This is a highly modified SteppIR 3-element antenna. I used three of the 30/40 meter dipole driven elements instead of the normal SteppIR elements. Each element has a shorting relay in it so it can be used either as a parasitic element or a driven element. The outer two elements are used on 40M as a driven elment and a reflector, and all 3 elements are used on 30M. Of course, it also uses all 3 elements on 20-10M and 4 elements on 6M. The antenna gives 6.2 dBi gain with 20 dB F/R on 40M and 7.0 dBi gain with 22 dB F/R on 30M. The elements are 39' long tip-to-tip, the boom is 18.5' long, and the turning radius is less than 22'. The boom is 2.5' longer than the normal 3 element SteppIR to support the second set of fiberglass tubes that the reflector uses. The antenna supports FWD, 180 and bi-directional modes on all bands, including 30 and 40M.
Please note that SteppIR does not sell this antenna yet. This is a prototype that I built to prove the design. SteppIR is planning to produce it starting in 2009.
Here's another view.
Here's a 6M version of the antenna that I built for rover operations. This antenna has a turning radius of 48" so it is small enough to rotate while driving or for use in an attic. The elements are fixed length and provide good performance from 50.0 to 50.5 MHz. Foward gain is 8.2 dBi (about 6.1 dBd) and F/B is better than 25 dB. This is about 7 to 8 dB better than a halo and only 1/4 dB down from a full-sized 3 element M2 yagi. The boom is 72" long, the driven element is 90" tip-to-tip, and the director and reflector are 66" tip-to-tip. I'm currently using an M2 T-Match from a 6M7JHV antenna, but will change to a 2.25:1 Unun/Balun for an improved match. This will allow me to shorten the driven element a couple of inches and is quite a bit cheaper than the M2 T-Match.
I have also designed four- and five-element versions of this antenna using 10' and 14' booms, respectively. The four-element design has a forward gain of 7.1 dBd and the five-element design has a gain of 8.1 dBd. When used for rover or portable operations, all three of these designs can be transported fully assembled on top of a vehicle, allowing quick setup at each stop.
I'm playing with a way to mount the antenna on my Toyota Tacoma.
The ad for the SteppIR Dream Beam 36, the big-brother to my antenna. This antenna was on display at the 2008 Visalia DX Convention and also at the Dayton Hamvention.
Copyright 2004-2008, Clay Curtiss, W7CE. All Rights Reserved.
Unless otherwise noted, all photographs Copyright 2004-2008, Clay Curtiss. All Rights Reserved.
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