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Issue #5- An Expensive 7 Band Dipole?

By Dave Jensen, W7DGJ

 

Summer in Arizona isn’t necessarily “antenna time,” but as any ham knows, when antenna issues plague you, it doesn’t matter whether it’s snow in Michigan or 110 degrees in the sun in Arizona. For me, I had recently updated the shack to include a new linear amplifier, and my homebrew dipole wasn’t really going to continue to do the job. That antenna was fine for my “100 Watts and a Wire” station, but when operating at close to legal limit there would be some serious reconfiguring necessary, some of which might have me break a promise I made to my XYL.

 

My wife and I have had many discussions about antennas. She hates them, and I think they are things of beauty. While we don’t live in an HOA and have a few acres to play with in rural Scottsdale, I still watch what I do to keep Linda and my neighbors happy. A tower isn’t in the cards because of my promise that I would keep all my antennas “mounted on natural objects in the yard,” and as camouflaged as possible. Picture a 17-foot, 2-Meter vertical springing out of a shrub that stands no more than four feet high, and that will give you some idea of what I am up against in my piece of heaven here in the desert.

 

Arizona isn’t the best place to be stringing up long dipole antennas that were made for those regions of the world where large trees abound. I would just love to have a few majestic oak trees in my backyard that require a tennis ball shooter to get the wires up and over. . . but no, instead we have a completely different set of rules for installing antennas in our native landscape. Rule #1 is to wear protective clothing because a variety of cactus and snakes may be involved.

 

My last dipole antenna was strung between two 100-year old Saguaro cacti with a juniper tree in the middle for a very low inverted-V. Junipers and Palo Verde trees are great desert dwellers, as they are very efficient with their water needs and well suited to the environs. But a tall Juniper or Palo Verde would be 20 feet high, and that really pales in comparison to what you might have available for antenna support back in Ohio. We have nearly 50 trees in our 5 acres, but none of them are over 15 ft. tall. All of them are extremely prickly and not the kind of trees you see kids climbing in the summer.

 

Enter the Buckmaster

 

After doing the research, I decided to buy an antenna that is built for a setup like mine. I found an off-center fed dipole produced by Buckmaster (sold through both DX Engineering and Ham Radio Outlet at about $375) that offers a 3000-watt rating and where optimum performance on seven bands is achieved via Arizona-style height requirements: 32 feet in the center and 10 feet on the ends. While I had no idea where I’d get the 32 feet of vertical rise for the center of my inverted-V, I knew I could find a cactus or shrub to hold up both ends at merely 10 feet. I kept my fingers crossed and ordered the Buckmaster, despite my initial concerns that no packaged dipole could be worth nearly $400.

 

When it arrived, I was happy to see that it was built like something for the military. The center balun was very heavy duty (and physically heavy as well), and the 135’ of wire and remaining components looked equally brawny. I swallowed my pride that I hadn’t built it myself and set about trying to find some way to get the center of my new antenna more than thirty feet off the ground. The negotiation began with my gal, and we settled on an extendable fiberglass pole by DXE, mounted in concrete, with a 35 ft. height and a non-obtrusive color. (Of course, as in any marital negotiation, it proved far costlier than the price of the fiberglass pole alone, if you get my drift.)

 

There’s another reason why I will probably never own a large tower, and this is the first time I’ve ever put it in writing. I’m afraid of heights. (There, I’ve said it.) Whether it’s standing on a ladder and changing an HVAC filter in a house with 13-foot ceilings or climbing an antenna tower with the best protective gear – that’s not me. That’s why God invented the handyman, and long ago I found a solid assistant for projects like this. Gabriel has worked on many antenna projects. . . he’s not a ham, but he often comes up with great ideas and generally seems to follow directions well. That is, until the Buckmaster project.

 

We had secured both ends of my new antenna (135 feet long) to their respective positions on Juniper trees at the required 10’ mark, and the middle pole had been sunk into its pad and was now stabilized. Soon the extension would be brought up to its full height. I handed Gabriel a bottle of bright green Liquid Electrical Tape and described how I wanted to protect the coax connection under the Buckmaster’s balun. My responsibility was to bury the LMR-400 and I went about digging a trench, confident that my handy friend would be fine at the top of his ladder with the sole job of getting a good waterproof seal on the PL-259. 

 

A few minutes later, I looked back and saw that Gabriel had unscrewed the PL-259 connection and was holding my coax in his hands while he painted the LMR-400 termination, inside and out, with bright green liquid tape. I could have soldered on three new PL-259’s in the time it took me to clean out that green gunk from inside the formerly shiny new connector. From that moment on, I now handle all electrical elements of my antennas.

 

In the Shack with a New Antenna

 

Because a Smith chart seemed a bit of a stretch at the time, I did the next best thing and hooked up a QRP radio to run WSPR through the Buckmaster, allowing it to run overnight so that I could check the resulting map on the WSPRNet.org website in the morning. The antenna is clearly more directional than the usual dipole, and in my location showed a bit of a preference for the Southeast with a hole to the Northeast, but both were minor issues that I consider acceptable. It appeared to be getting out extremely well. I spoke to the owner of the company and he told me that some hams have placed two Buckmasters in their yard, with the opposite placement in order to switch between them for best signal.

 

As I worked it over with my analyzer, I discovered that it didn’t require any additional tuning on my part. It was the first time for that . . . every other dipole I’ve used has required some snipping or fiddling to get the SWR as low as possible on my preferred frequencies. I found the Buckmaster very flat (below 1.4 to 1) on 10, 12, 17 and 20 meters, with a smaller sweet spot and a rise to 1.7 – 1.8 on the band edges of 6, 40, and 80 meters. In two or three cases I would need to use a tuner to improve performance, most notably on sections of 40 and 80 meters where I regularly attend nets, but overall it seemed to be resonant across those 7 bands, as promised.

 

Combined with my new power amp, the Buckmaster had made a considerable dent in my ability to reach DX, which has always been one of my ham radio loves. I rated the build quality on this product an A, and the user experience an A as well. If I had a rating for value, I would have dinged it a notch or two because it stung a bit to spend that much on a wire antenna.

 

73 for now,

 

Dave

 

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Dave Jensen, W7DGJ

Dave Jensen, W7DGJ, was first licensed in 1966. Originally WN7VDY (and later WA7VDY), Dave operated on 40 and 80 meter CW with a shack that consisted primarily of Heathkit equipment. Dave loved radio so much he went off to college to study broadcasting and came out with a BS in Communications from Ohio University (Athens, OH). He worked his way through a number of audio electronics companies after graduation, including the professional microphone business for Audio-Technica.  He was later licensed as W7DGJ out of Scottsdale, Arizona, where he ran an executive recruitment practice (CareerTrax Inc.) for several decades. Jensen has published articles in magazines dealing with science and engineering. His column “Tooling Up” ran for 20 years in the website of the leading science journal, SCIENCE, and his column called “Managing Your Career” continues to be a popular read each month for the Pharmaceutical and Household Products industries in two journals published by Rodman Publishing.


Articles Written by Dave Jensen, W7DGJ

This page was last updated December 20, 2022 22:04