Flat Black and Chrome
The hurricanes blew through Florida in fall of 2004, and cleared the back of my property of about 50 tons of oak and pine trees. The loss of these trees to the aesthetics of my property was tragic, but it did give me wide open spaces for experimenting with some verticals. My first attempt was to put up a stock Butternut HF-2V I had laying in the garage. I placed it in the ground, and started to lay some radials. The antenna worked pretty well. Its bandwidth on 80 was only about 30khz. Next I added 30M to the antenna by placing a stinger cut to about a 1/4 wave. I put a light 3 foot cross member about 1/3 the way up the vertical, and ran a wire from the feed point out to the cross member and then back to a piece of nylon twine which was connected back to the vertical near the 30ft level. (An example of a cross member can be seen in Figure 3 at the top.) There was some interaction between 30 and 40 requiring some retuning. This gave me all of 30, all of 40 and 30khz of 80 with good to excellent SWR.
I decided to try to improve the efficiency of the Butternut by lengthening the antenna, and losing the 40M coil. I extended the antenna to about 41 feet. I had to retune the 30M element as well. I didn't notice much improvement. I next ran a rope between a couple of pines, and put up a 55' T style wire antenna and fed this as a top loaded 1/4 wave vertical on 80M. I did extensive A/B testing between the Butternut and the T on 80M and found the T was marginally superior. I next placed a 60ft piece of wire out a little farther along the rope and built a parallel tuner, and end fed this on 40. I extensively A/B'd this antenna as well and found it also to be slightly superior to the Butternut. It's bandwidth was not quite as good as the butternut, but over many contacts and listening sessions on DX from every direction the end fed antenna 1/2 wave was clearly marginally superior. I also loaded up the 80M T on 30M through a tuner and found it to be a good performer on 30M. I put up a 160M inverted-L off in another direction with the vertical portion about 65ft high suspended by a tree. Each of these antennas could be chosen by means of a remote coax switch. These experiments gave me good indication of how the finished product would perform. If all one could get up are these tree suspended wire verticals he would still have a good system on 160, 80, 40, and 30.
I next decided to formalize this design as an all in one multi-band vertical, with some aluminum as the support instead of trees. I made a 65ft 2 inch diameter pipe out of 10 6' sections of 2 1/8 inch tubing from Texas Towers. I joined each piece with a 2 ft length of 2 inch tubing. The top was 2 Inch tubing extending out to resonate the antenna. I found the antenna was long 3.5 mhz and wound up cutting it back to about 59ft. (I think this length differential is a function of the way I attached my radial system, and if you decide to try to duplicate this I would plan around the formula predicted length and not around my experience). This gave me resonance at 3.6 mhz with 1.35:1 at 3.5mhz 1.9:1 at 3.8mhz. I guyed the tubing in 3 directions, and used a modification of the N6RK falling derrick method to get it vertical. Figure 0 is a picture of the vertical being raised by this method. I use 2 x 1 1/4 inch 10ft EMT joined by 2 ft of 1 1/2 in EMT. This piece telescopes into the other 8ft of the 1 1/2 in EMT to give a derrick of 27ft. In retrospect I wish I had guyed the vertical in 4 directions and suggest to anyone deciding to copy this project to guy in 4 directions. It makes the raising and lowering much simpler. I use a modification of this technique. Note how the derrick is steadied by the guy ropes on each side of the post. For my vertical I use guy ropes on the vertical and guy ropes on the derrick. I took 2 pieces of black pipe and pit an eyebolt in each. I pounded the pipes into the ground along a line co-linear with the pivot of the vertical. I tie the guy ropes from the vertical and from the derrick temporarily to these pounded in pipes for guying while raising and lowering the antenna. These pipes and the center pivot of the vertical form the fulcrum around which the entire system rotates. This basically makes 2 triangles at 90 deg to each other. The first triangle is horizontal on the ground and the second is vertical. As the vertical is raised, the triangle formed at the apex of the derrick becomes horizontal, and the triangle formed by the apex at the vertical becomes vertical. If you take a piece of paper and cut it into a square and fold it along a diagonal to give 2 triangles at 90 degrees, and pivot the thing along the axis of the fold you will get the idea. A rope on the back of the derrick runs through a block and tackle to a tree that is 90 degrees from the pivot axis, and about 35 feet behind it. If you don't have a convenient tree a screw in guy anchor will do the trick. Make everything square. Even a little torque on the aluminum will be magnified by the time it gets to the 59 foot end. I have a tag line which runs up the vertical to give me the 4th set of guys. I tie these tag lines off to the vertical when not in use.
With the guys fixed in this fashion the vertical can be raised and lowered by one man easy as pie. I have to temporarily guy the antenna in 4 directions to get this to work smoothly. I use a block and tackle to give me a little advantage when raising or lowering, and I tie some loops in the rope as I raise the antenna so I can loop them around a post about 20ft away from the point where the rope exits the block. With this technique I can pull the antenna up in intermediary steps, and I can make any adjustments I need to during the raising or lowering. There comes a point where the weight of the derrick falling down will over take the weight of the vertical as it goes up. I have a saw horse next to the derrick that I can rest it on to keep the vertical from being raised too quickly as the derrick falls. Easy does it.
I decided to incorporate 40M and 30M half wave vertical wires into this antenna as well. Figure 1 is a picture of the finished antenna. You will note the antenna basically looks like a typical 80M vertical. The 40M and 30M elements are laced in the rope guys. Figure 2 is a diagram of how the wires are laced. I left these files large so they could be expanded for close up inspection. The red wire is the 160M inverted-L in the foreground of the picture and is a separate antenna from the vertical system. The long black wire is the 61ft 40M vertical, and the shorter black wire is the 30M 44 foot antenna. The white represents a piece of rope that suspends the wire from the upper set of guys. All wires are terminated in an insulator. In addition I use an insulator fixed to the guy line as a guide to hold the wire as it passes through. The wires are free to move through the insulators in the guys as the antenna sways. This avoids any kind of abrasion to the rope.
Figure 3 is a shot of the tuners for 40M and 30M. They are housed in plastic shoe boxes from the local dollar store. Figure 4 is a shot of the tuners with the cover off the boxes. The coils are #8 and #6 solid copper wound on a 2 3/4 inch OD PVC coupling. Figure 5 is a close up of the 40M tuner. The caps were surplus 120pf caps I had on hand and are good for 1500W power levels. The 30M tuner is tapped such that I can move a couple of taps, and tune the antenna as a 5/8 wave on 20, since 44ft is just a little longer than 5/8 on 20. I can still tune the 80M section of the vertical using a tuner in the shack as a 5/8 wave on 30M. So if I want, in a few minutes I can field configure the system such that I have: 160 inv-L 1/4 wave, 80M 1/4 wave, 40M 1/2 wave, 30M 5/8 wave and 20M 5/8 wave. I don't operate much 20M but it's nice to have the option.
Figure 6 is a close up of the 160M feed point for the inverted-L. This antenna uses a hairpin solenoid of 2 inch diameter and about 17 turns. I may rewind this to a 3" diameter and less turns, which should give a higher Q. It also uses a short piece of solid wire for linear loading to fine tune the antenna for 1820khz. The SWR at 1.8 mhz is about 1.35 and around 1.92 mhz it reaches 2:1. This antenna does a fair job for DX on 160. I spend very little time actually tuning 160, but I have managed 50 countries, over the past season with almost no effort. My job keeps me unavailable at sunrise and sunset on most days, so the countries I have worked are catch as catch can in the evening hours. It is certainly better than the Butternut with the 160M coil added.
Figure 7 is a shot of the coax switch. I modified the controller of this unit so it follows band changes on my Ten Tec Orion. All of these antennas are tuned to exhibit better than 1.2:1 at resonance so band-switching is basically a point and shoot operation. Click a band and hit the key. If I have the amp running, I have to switch that, but the settings on the amp are very reproducible so I don't really have to put a carrier on the air to tune-up unless I wander into parts of the band I don't normally frequent. There is very little interaction between the antennas. I can tune any one and the others basically do not change resonance. All the antennas share the same radial field. I presently have about 24 x 1/4 wave radials on 80M and another 10 x 100 footers for 160 connected to the radial termination plate.
I had the coax switch and the caps in the junk-box. The aluminum was about $350 shipped from Texas Towers. I use #14 solid for the radials 5 x 500ft rolls at $15 per roll. The 40M wire is 61ft long, and the 30M wire is 44ft long. I use stranded #14 for those. The 160M inv-L is 137ft of stranded #12. The coils are wound out of solid #6 or #8 from the hardware store. I use 2 pieces of 1 1/4 EMT and one piece of 1 1/2 EMT for the derrick at about $40 total cost. The rope is 1/4" double dacron. I have probably another $50 in stainless hardware. The insulator and base for the antenna is from A9KW at zero-five antennas. This is a very nice base for this vertical. You could use a piece of fiberglass from MAX-GAIN, the 2" OD 1/4 wall thickness fits inside the 2 1/8 inch tubing perfectly. I would use a 2 foot piece with 11" in the vertical and reinforce the fiberglass below the vertical with a piece of 2 1/8 about 11" long. So all told it would cost about $850 to get this antenna up and running from scratch with no parts from the junk-box including the purchase of a coax switch and 100ft of Buryflex. What you get is a no compromise competitive multi-band antenna. If you bought the Butternut HF-2V new with the 160M and the 30M coils it would run about $775 dollars if you include 2500 ft of #14 radial wire and the same 100ft of Buryflex. So the antennas are comparable from a price perspective. From a survivability perspective the home brew multi-band is far better. The Butternut is rated to only 60mph. It has a smaller foot print since it doesn't need guys, but a good wind would send the Butternut to the ground. I expect the home brew antenna will survive 100mph and not blink. I've already seen 50mph in a storm on this antenna and it didn't blink. The Butternut would have been toast. I don't know about ice loading, being a Floridian, so that may be something the builder might want to take into consideration.
In the end I painted the antenna flat black for aesthetic considerations. It blends in more with the scenery when the XYL is in the kitchen looking out on the backyard. In my youth I had an old Harley K model that I stripped to the bone and painted it flat black and chrome. No decals no nothin'. Just a motor and wheels, flat black and chrome. I sold it when I went off to med school. I needed the dough to pay the tuition. I never bought another. Since then I've worked on too many head injury patients to tempt my fate, and I think a geezer on his Harley looks a little ridiculous, but I always lamented the loss. This antenna reminds me of my old Harley. If you look closely, where the wire verticals attach you can even see some "handle bars".