Coping: Ure’s Monster Antenna Project

If everything went according to plan, my buddy the retired Major from Gig Harbor will just be stirring as he and his wife arrived at Uretopia Ranch last night. Last, as always, and now done with kibitzing until past midnight.

They’re on a stopover enroute to a medical conference in SoCal next week. And we have three agenda items.

The smaller of them I’ve already described in some detail. The frequency-sweep approach to B-field phenomena which may relate to anti-gravity. That’s one.

The second is “The Light Crown Project” detailed in Peoplenomics a week, or so, back. We will be building up a couple of Light Crowns testing them to see if they offer any effects and, if yes, are they replicable?

The third – which I lie to myself as related to “prepping” – is to build the biggest, longest, meanest 80 meters ham band long wire either of us has ever seen.

Frequency and Wire Length

Here’s a simple thing to understand: A lot of radio antennas are ¼ of a wavelength.

There is a formula for antenna length that you will run into when you outgrow the limits of a Technician Class license and want to work the world on that amazing spectrum between 3 and 30 Megahertz.

You know how AM band radio bounces around at night? Well, the HF radio spectrum is doing this almost all the time, with occasional short time-outs for geomagnetic storms of solar flare arriving. The highest frequency that can be used for bouncing is called the MUF – short for maximum useable frequency.

Most of time time is spend on the 20 meter/ 13 MHz ham band. I like talking to people in Europe, down into the Middle East, and Africa. The “right” antenna to do this is a 3-element beam on an electrically operated crank-up tower.

When I was to “go long” – up goes the tower. As it goes up, the take-off angle of the signal comes down closer to the horizon. A single hop to Europe.

At night, the 14 MHz band closes down. For years, I have enjoyed a CCD antenna. It’s use has been on the 7 and 3.5 MHz bands. Short for continuous current distribution it has a very low noise floor for receiving. But, since it is comprised of dozens of capacitors, it doesn’t “get out” as well as a dipole (two wire) antenna. Everything is a compromise.

Most ham radio buffs, who are active on the 80 meter band, have only a few options. One is to put up a 130 foot wire, fed in the middle. This is a Dipole.

If the dipole droops down toward the ground atg the ends it is called an “inverted vee.”

There are other designs, though, that offer some gain over a simple dipole. The plus is they can more than double effective radiated power. The minus is that they eat real estate like it’s going out of style.

An example of such is the Double Extended Zepp and antenna. And you can find online calculators, like this one, to help you figure out the dimensions. I don’t think West Mountain Radio would mind me sharing the real estate problem that comes with a Double Extended Zepp antenna on the lower end of the 80 meter band.

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Hate to say it, but most hams don’t have 336 feet of real estate to lay out such a behemoth. If you do, you can achieve an effective radiated power of about twice what a simple 130 foot dipole would deliver.

About here, you have permission to slap your forehead. “George has lots of land…”

Ah, now we get into the design part. We have two ways we can design one of the world’s cooler long wire antennas: One way would be to put it up using ladders – which would get us up to about 15 feet above ground. Or, we would rent an all-terrain scissor-lift and that puts us up at 35 feet. I don’t suppose you’d care to guess which one we’re aiming for?

Except that the one at the rental joint needs repairs…but I’m leaning on them to “get ‘er done.”

Which leaves working out the actual layout.

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The cold side of the antenna goes to the short side and the hot side to the longer. 558 feet by 186 feet.

Talk about a signal on 80-meters: If we can get the scissor-lift it should look like this:

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Our alternative (if we are ladder-bound) is to put up a conventional off-center fed dipole of 90 feet on one side and 45 feet on the other and do some tower welding. Then we could get it up to about 50-feet at the center and it would get out fine.

Or the Double-Extended Zepp.

Construction note: Continuous duty rated 3 kilowatt balun at the tower.

Either one would be satisfactory. It’s just a matter of what equipment is available.

Ham radio is always like a three-in-one fishing trip.

You have an antenna selection to make. Then you have an equipment selection to make since we have a number of radios to choose from.

Last, there is the band and mode decision.

Any change in one will change everything else.

Running the TenTec 540 in Morse code is different than running the Kenwood 590 and linear amplifier on SSB. And that’s all different from the Yaesu 757 when that’s set up for slow-scan television or PSK-31.  Or one of the tube rigs…ham radio heaven out here.

But that’s why the hobby still interests both of us after more than 50-years each working at it.

Yeah, we’ve done our share of public service on ham radio (my introduction was in the wake of the 1964 Alaska earthquake). But more than anything, it’s fun messing about in areas where most of the moving parts are invisible, and therefore magical.

We’ll see how the scissor-lift deal works out.

Write when you break-even,

George@ure.net

Comments

Coping: Ure’s Monster Antenna Project — 8 Comments

  1. George,
    In Australia we had a giant 40 meter rhombic antenna at our Ham Station in Woomera left over from the 50’s. It used a pulley system mounted to 20 meter or so tall telephone poles, so you could raise and lower the wire so you could do maintenance. Worked beautiful to talk to the states. VK5KBV

  2. Some sign companies have bucket trucks that go way up in the air Past 35 feet and they have extension ladders that go I forget how many hundreds of feet they go so yeah check your local sign companies and see if they can help you for a day to install that because they would be cheaper than other people I believe to install something that high compared to using the regular crane of course some of those ladder trucks do have cranes on them so in conjunction with the bucket truck and the latter crane you could get the job done and go a lot higher

  3. George, It has been too many years since I was a Ham, (early 1960’s), nut isn’t there a sweet spot for the antennas distance from the ground with respect to its frequency. That is, it might be 33′ rather than 35′. I forget what the name of the effect was’ or even if it had a name.

  4. I’m interested to see how this antenna works out for you as I’m always looking for ideas to compliment my 550′ horizontal loop…

  5. I cant find the website now, but a guy on Yahoo showed a website about sonoluminescence. Seems MIT figured out how to make plasma by shooting some wave of megahertz strength into a fluid (somehow involving beryllium?) and obtaining temperatures as hot as the sun. This could solve all our energy woes. The reason it was being presented was due to a story about their funding being cut off once successful, thought to be due to the PTB’s harvesting of oil in Somalia. Like Tesla’s work being cut off- as you say, history sometimes rhymes.
    So..hopefully you wont be making plasma with this radio wave tower!

  6. Right after Stan and I got married we moved to a place that had multiple duplexes – and stayed there for about eleven years. The next property over was home to a ham radio operator, who had a good sized antenna and a modest house – and a blackberry bush of impressive size that had enveloped a garage with a Volkswagen just barely visible under the vegetation.

    Well, he kept the ham radio ‘stuff’ in good shape apparently, though toward the end of our living in the duplex, he passed away. And it was a surprise that under that gigantic shrubbery was a rather large boat.

    Those blackberry bushes will take over everything!