Here is a link to the Texas Tornado antenna plan, it is from 1965, a v beam, with 10 db gain. I will get this built , when I find more wire. https://www.americanradiohistory.com/Archive-S9/S9-1965-09.pdf
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Base Texas Tornado High gain wire Antenna
- Thread starter xm49north7
- Start date
S&W357
$upporting Member KO4RJD....WDX-556
Every bit of that looks interesting. Read some and will read the rest of it. Thanks!
Ya, I went thru every old back issue of those old cb mags I could get my hands on, and some old ham ones, looking at home built antenna designs, yes I am an antenna crazed individual, laughs. This one just caught my attention with the huge gain, the simplicity of the design. I have the space for it, I am in the middle of 20 acres. For me the only down side is it has to stay put , there is no rotating this beam, so it will be all one way. Maybe have to build 2 back to back if this one works, laughs, this is also possible.
Article just says 10 db of gain. , I know article is not anything near science, it was written in 1965, when a cb radio had one knob and a mic. I just have a thing for wire antennas, there is some info in the ham world on v beam wire antennas that do quote high gain as well, I do not have the info at hand. If you google v beam antenna you will find a few.
Dam another one to build, laughs, thanks for that , this is a very cool design, not sure why he did not make some directors, went with 3 reflectors and the driven, maybe don't need them or they don't ad much or the ground is the director?? Here is the pdf for the portable yagi. I am going to need more wire than I thought. This would be easier than the tornado, and it can be swung to new positions, I am liking this. I feel for those ham guys and all those bands to cover, we have it easy on cb radio. http://www.arrl.org/files/file/Technology/tis/info/pdf/0111035.pdf
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I did some modeling on this myself. I had to go longer, even using copper wire, to get it to match with the balun the article mentioned. I found 264 feet and about 6 inches is where that came to be. Mind you, in the model the wires will be straight, while in reality the wires will sag to some extent. Also, I used bare copper wire, so if the wire they used has an outer covering, that will add a velocity factor, typically very minor however on a wires this long compared to a wavelength that adds up in raw distance.
I mounted the antenna 20 feet above ground, which is average ground. This is the pattern I get.
[photo=medium]5673[/photo]
Definitely a bi directional pattern. 13.1 dbi peak gain, but there is a 60 degree area that has mostly between 7 and 8 dBi gain. In the reverse direction we have a little over 9 dBi gain, and a 60 degree area that is mostly 3 to 5 dBi in gain. Also, as the article points out, this gain is horizontally polarized, not vertical, so keep that in mind.
When it comes to wire length to SWR, impedance, and gain, I get these graphs. You can click on them to show larger versions. The numbers at the bottom of these graphs are in inches. Yes the wires are over 3000 inches long, that is not an error. That should put in perspective how long these antennas are.
SWR
[photo=medium]5679[/photo]
I applied the 4:1 balun to this, so it is in perspective.
Impedance
[photo=medium]5678[/photo]
In this case, the R component of impedance does not change much, most of the changes comes with the X component (reactance/resonance).
Gain
[photo=medium]5677[/photo]
As we can see, gain doesn't change significantly with the changing length of wire. This suggests that whatever length of wire you come up with to get a good match will not change the overall gain much if at all.
Now to look at what a tuned version of this antenna will do over the 40 channels of the CB band.
SWR
[photo=medium]5682[/photo]
As this is specifically covering the CB band, the bandwidth of this antenna is narrow, very narrow. You can expect a 2:1 or lower SWR on just over half of the channels of the CB band. Further, if you use the "balun" design that the article suggests as opposed to a wider bandwidth version like I used, that will narrow the bandwidth of this antenna still further.
Impedance
[photo=medium]5681[/photo]
I couldn't get these to line up how I wanted, so they don't match the impedance chart from above, however, the info is still readable.
Gain
[photo=medium]5680[/photo]
As you go up in frequency, we see gain rise to some small extent. However, it isn't enough of a change that you will ever notice the difference. Much like the gain chart above, their is little change.
I hope this helps put this antenna design into perspective.
The DB
You are the man; thank you so much, this is an amazing amount of info, everything needed. I would build this for skip, cut for lower side band 38, the horizontal should be no problem with skip. So we have the proof she has 10 dbi, very cool. This makes me want to find that spool of wire even more. One of the main attractions on this antenna is the low height, it is long for sure, but not hard to maintain at that height. Those long wires would also be great for shortwave listening. So what do you think of it, worth a build, to big, to narrow, a fun project???
Shadetree Mechanic
Delaware Base Station 808
Interesting how long the wires are. I guess it's the angle of the V that makes this work without cancelation from having the radiator too long? I might have to play around with this.
Priced the wire out up here in Canada at the home depo today, 85 bucks per 500 foot spool #12 stranded, so a couple spools would get er done. I will start getting some posts cut, making insulators and so on.
Hey xm49north7, welcome to the forum.
That article is very interesting, but it sounded pretty iffy to me, so I also modeled it just to see what it looked like.
Below are my two models in the PDF files at the bottom. Don't use "save" in the PDF window, click on "Open With" instead.
1. is in Free Space, which has no losses in the model and is very similar to the model DB posted. I used the balun noted in the article which is generally said to be very narrow banded. That is OK though. If you plan on building one of these you will have to deal with it being very narrow banded. It won't even cover the entire CB band without seeing >2.00:1 SWR.
2. is over Real Earth, which has the losses added back to model #1, and it is above Earth mounted 6' at the feed point and 10' feet at the far end. This model indicates the gain we see noted in the old S9 article that xm49north7 posted for us.
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Good stuff Thank you for your hard work on this, much appreciated. . Well it looks worth a build to me . Good gain. I can manage about 20 feet at the feed and maybe 16 feet over the ground all the way. Swr is super narrow for sure, so would need to hit this for maybe channel 30 for skip give maybe 28 to 38 ok. That 3d wire frame plot is very cool.
xm49north7, I raised my model over Real Earth up by 9' feet and here is an overlay of these two models of the Texas Tornado. Higher drops the take off angle (TOA) 1 degree and the gain increased 3.5 dbi.
BTW, the (*) beside the title of the model in overlays shows us the active model in the gain and angle details at the bottom right on the image.
Just a guess about matching this monster. Since it is so narrow banded...I would suspect it would also be difficult to tune...you just don't have a big range for error, and don't figure to go up or down in frequency very much...unless maybe you have a auto-tuner in your radio.
If you go forward in this project, maybe you can get Steve to give you a clue to his wide band balun idea.
BTW, you can use the (+) or (-) at the top of these PDF files to zoom in or out.
BTW, the (*) beside the title of the model in overlays shows us the active model in the gain and angle details at the bottom right on the image.
Just a guess about matching this monster. Since it is so narrow banded...I would suspect it would also be difficult to tune...you just don't have a big range for error, and don't figure to go up or down in frequency very much...unless maybe you have a auto-tuner in your radio.
If you go forward in this project, maybe you can get Steve to give you a clue to his wide band balun idea.
BTW, you can use the (+) or (-) at the top of these PDF files to zoom in or out.
Thank you so much, tuning is the worry on this for sure. I will look into the wide balun for sure. I just run normal cb radio so I don't think the radio will be much help on this. It will have to be trimmed to fit. For some reason in my head I thought that with 292 feet per side almost 10 wave lengths long, that all that wire would make it easy to trim for swr. I think not being a loop makes it harder as well, I find loops the easiest to get tuned. I have seen beams like this done as loops with resistance or capacitance added at the end of the horn, not sure how this effects the gain and tuning.