Moved The Tune-A-Tenna

I had a few problems with the initial location where I’d put the Tune-A-Tenna.

  1. Due to surrounding structures, etc., I could only orient the legs E-W, which is the shorter dimension of my lot.
  2. Too close to my wife’s office, so QRO was out of the question (while she’s in there).
  3. Metal mast interacting with the antenna.

Well – I have some fiberglass pole for a roof snow removal tool that I seldom use. It’s 4′ sections that snap together. So this past weekend I took the Tune-A-Tenna off the metal mast and moved it. I have it at 24′ now, and have one more section of this blue fiberglass pole, but I don’t think I will attempt 28′ until I can figure out a way to attach a bunch of guy lines to it. It’s too flexible for this amount of weight.

Building a higher (hoping 40′ to 50′), more-rigid mast, with at least the top 8′ of it non-conductive, is in the planning phase. When I get that figured out, it will undoubtedly include a pulley system so the main unit of the Tune-A-Tenna can be brought down to the ground gently – no climbing.

However, such as it is, here’s the antenna leg orientation:

With it in this orientation, when I lengthen it to best tune on 3.8Mhz, the ends of the elements are only a couple feet off the ground. Would I LIKE to have a resonant dipole on 160-meters? Yes. But I do not have the acreage. If I ever get on 160, it will probably have to be a loaded vertical, or an hour-glass-shaped sky-loop (no, I don’t think I’ll be doing that). Anyway, on 80-meters, the best SWR I can get is probably a bit over 1.5:1, and I’m sure it’s not a great performer.

On 40-meters, however, this thing dials in such that the SWR meter on the radio doesn’t even light the first little segment – no antenna “tuner” is even in the line. Resonant or nothing. No compromises.

I ran WSPR on it for approximately 12 hours.

Roughly 4-6pm, just after getting the Tune-A-Tenna up. Driving approximately 2 watts on 40-meters.
By about 10pm that same evening, my 2-watt signal had been picked up overseas.

By 6am the following morning, I had more hits in Europe & Africa, plus Australia. Then again, 2 watts is a lot for WSPR. I need to do some calculations to try to drive the antenna with something closer to 500mW. That’s when I’ll get a better idea of how well this Tune-A-Tenna performs.

On a completely coincidental note, a few days after I first put the Tune-A-Tenna up, I noticed the RF noise floor jumped way up here. I’m used to having S5 to S7 noise on 80, but not nearly so much on 40 or higher. Well…

That, my friends, is an S-9, hashy, broadband noise floor, on 40-meters. And it’s new.

Fortunately, another thing on my to-do list is to install an emergency power cut-over switch panel, so a few of our household circuits can run on a generator during a power outage. This will give me an opportunity to kill circuits one-by-one and see if the new source of noise is in our house or somewhere else. I hope it’s here. I don’t want to go chasing interference in the neighborhood. Ish.

By Kelvin D. Olson

Not saying much here. What you really want to see is https://mastodon.hams.social/@kelvin0mql

2 comments

  1. Here’s what I’m thinking:

    1. Set the radio power to 100w (max).
    2. Tune WSJT-X and adjust the power slider until the radio shows it’s outputting 10 watts (a rough approximation at best). Note the slider position (e.g. it showed me -27.9db when I did this on 10-meters just now).
    3. Dial the radio power down to 5w (min).

    Theoretically, then, I’m as close to 500mw as I can be without expensive test equipment.

    Does that seem reasonable?

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