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[Articles Home]  [Add Article]  

An Inexpensive and Effective 20-Meter Vertical

from Greg Danes, KJ4DGE on February 16, 2019
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An Inexpensive and Effective 20-Meter Vertical
By Greg Danes, KJ4DGE

The reason for this venture was lack of space and stealth to a degree. Also, I wanted something I could put up is a place clear from trees and the house. I am fortunate to have a semi-next-door neighbor with a stand of bamboo on their property. They are more than happy for me to cull it from time to time. The tallest pieces that are healthy are around 20 feet in height. This was the non-conductive mast I decided to use, and it blends in more than a metal or plastic pole.

I could have used a simple length of wire at 16.5 feet for the radiator but instead chose a bought mono-band dipole that I had no success with tuning or mounting in this small yard. The dipole now cut gave me 2 16.5 feet section the first of which I secured to the 20-foot bamboo pole. See pics. Next, I needed at least 100 feet of coax to run from the window of the house along the ground and to the base. Then I started to experiment with it.

I found even with an air-wound balun for a current choke I was losing a lot of power in this setup and had excessive SWR across the bands. So down it came and remembering the articles I had read on this and having built a current balun that worked well in the past for 40 meters I built a new one on a liter bottle of Coke using 6 neat turns of the feed line. This worked to get me about 75 watts out but the SWR remained the same with only a small portion of the 20-meter band around 14.260 being 2.1 as measured by the FT-990.

Knowing that any ground plane does better with more radial and with the right angle, I cut 3 measured 16.5 foot wires to add to the bottom of the current choke side of this mess running at 45 degree angles that allowed me to still walk around the house without having to duck under them :-)

I also tied these radials off so that would act as natural guy wires with a purpose so to speak.

See above and yes that is an iron railing next to the steps that lead down to the basement. Along with the 20-foot bamboo mast, I have a 5-foot metal bar as a brace to the bamboo and lashed to this, giving be an addition 25 foot height overall.

After several trips to the rig to check SWR, I found that now I was getting 1:5:1 and 100 watts power out across the entire 20-meter band! I did have to trim the white wire a bit in the picture as it was a guess and a mess when I measured it, but the results were more than I had wished for. No doubt the one radial couples with the railing a bit and gives a broader ground pattern but the angle I feel is the real reason for the SWR being lower.

All in all, about 2 hours of building and testing. And the results? Even with VERY bad conditions I checked into the SATERN net on 14.265 with an S7, was heard by a group of 7s and 6s in California and worked one with a S9. This was my first attempt at a vertical for 20 meters and the results are better than I wished for.

Experimentation s what its all about as hams. We have a leg up on fiddling with things until they work. You never know until you try.

Additional pics below:

Before you ask, No, the broken weed-whacker in the trash can is not part of the antenna...wait I could use the nylon spool from it for something! Now if anyone knows of a sure-fire way to kill climbing ivy...feel free to contact me. :-)

Best wishes from KJ4DGE

Member Comments:
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An Inexpensive and Effective 20-Meter Vertical Reply
by ONAIR on February 16, 2019 Mail this to a friend!
I have used bamboo to make many antennas! Great material!!
 
An Inexpensive and Effective 20-Meter Vertical Reply
by WB0OEW on February 16, 2019 Mail this to a friend!
Get's you on the air, well done. Even a few elevated radials work well and yes, I think angling them down a bit brings the input Z up closer to 50 ohms. Thanks for posting.
 
An Inexpensive and Effective 20-Meter Vertical Reply
by KB2ICN on February 16, 2019 Mail this to a friend!
Thanks for posting. In FL, I've seen some residents\businesses plant bamboo in a row for privacy. The stalks grow a few stories high. I'm now motivated to plant some bamboo trees.

Thanks for sharing!
-kb2icn Chris
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by KE4GNK on February 17, 2019 Mail this to a friend!
Uh, be careful.

Bamboo spreads by its underground roots, and in Florida, if you get enough rain in your area, it will take over your yard, your neighbor's yards, and quite possibly the entire neighborhood. We had a neighbor across the street in Florida where I grew up, and his entire yard was full of the stuff. It took a Bobcat, a big crew, and several days to clear it out when the house was sold. Only 9 months later it was visible again, above the single story house's roofline.

I'd suggest harvesting what you need from the wild, or buying dried sections. The stuff is as invasive as Kudzu in Alabama and Georgia...
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by KJ4DGE on February 17, 2019 Mail this to a friend!
Thanks for the warnings. I live in the business section of downtown Leesburg VA. The bamboo in question is part of a tiny strap of land that belongs to my neighbor across the street. Beyond this strip is a commercial parking lot. He and his wife prune it around the edges a a jester to the folks around us. The business next to our yard here put up a wooden fence 6 inches over our property line and unfortunately we have no money to fight them over 6 inches.

That being said planing a fence of out own directly behind their made of bamboo would be poetic. Bamboo can be used for furniture, piping, all kinds of neat uses. I also grow Morning glories from seed so know all about the dangers of evasive plants/weeds if not kept in check. I also use the bamboo for a 30 foot mast for 2/440, a stealth discone scanner antenna (also homebrew). Used it to cover a shed here with a tarp do to no ladder as a prop until I could position it then pulled them back down. loads of things use can use bamboo for.
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by SWMAN on February 17, 2019 Mail this to a friend!
Yes, once it gets established in a yard it is almost impossible to get rid of. You need a very very strong weed killer to kill it, almost like Agent Orange. Just be careful if you plant it, a little goes a long way. You may regret it later.
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by KJ4DGE on February 17, 2019 Mail this to a friend!
my main fight in this yard is climbing ivy on the side of the brick. Thought of C4 but that would ruin the brick :)
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by W8QZ on February 18, 2019 Mail this to a friend!
Have you tried Roundup on the climbing ivy?
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by KJ4DGE on February 19, 2019 Mail this to a friend!
No,
Not a fan of Monsanto. Next step though is to drill holes in the root and soak it in toxic but not as toxic weed killer. Damn Ivy actually embedds itself into the grain of the brick. Someone told me to power wash the side of the house but that would just get rid of the leaves I think, wish I had before and after pics of all the work I have done so far. The house was being eaten from the outside in. It actually was crawling into a spare unused room through tiny breaks in the window sill and.... well you get the idea.
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by AC7CW on February 19, 2019 Mail this to a friend!
When I was a kid people were making quad antennas out of bamboo. Construction is much simpler/cheaper than a yagi: Just use bamboo, twine, etc., tie the thing together, add coax...
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by KJ4DGE on February 21, 2019 Mail this to a friend!
Thanks for your support. Yeah it can be used for a lot of things. Martial artists use bamboo for staffs, kendo and other training weapons as its tough enough but won't crack your skull too badly weird huh?

From an antenna perspective it also is light enough to hold a wire but loose enough to sway in the breeze during a bad storm. Most rigid masts just come crashing down. W5CIA comes to mind. He had a monster beam down LA way and Katrina or one of those storms broke the crap out of his array. Still he made a lot of DX on that rig before it took a fall including me in Alexandria, OK not DX for him but I broke a pileup with 5 watts on 6 meters :)
 
An Inexpensive and Effective 20-Meter Vertical Reply
by KC1GCG on February 22, 2019 Mail this to a friend!
Hi Gregg. Thanks for the interesting article. I have a 5/8 wire verticle for 20 M that I enjoy using. It has 4 elevated radials. More info is on my qrz page if interested. I have an mfj 225 antenna analyzer that is a very helpful tool for when I want to experiment with things like angle of the radials and such. All that additional info besides just swr is really useful data.
Also a tip for those that do not have bamboo growing locally is Ocean State Job Lot stores. They sell packs of 8 ft pieces of mixed diameter making it pretty easy to join pieces with a proper sized dowel and some heater hose clamps. Even some Gorilla tape has held up well! I've used them for masts attached to 12 ft pvc to get some 25- 30 ft or so masts and also to support wires for various antenna experiments.
Keep on writing and I hope to catch you on ssb someday to chat antennas.
73. John K1jrf
 
An Inexpensive and Effective 20-Meter Vertical Reply
by WJ4VA on February 22, 2019 Mail this to a friend!
I have an R8 mounted on a 10 ft section of 2" waterpipe (with a tilt over base at the bottom) in the same fashion. My railing is a bit beefier though.
 
An Inexpensive and Effective 20-Meter Vertical Reply
by WB4M on February 22, 2019 Mail this to a friend!
I second and third the bamboo comments! A friend had a large, dense stand of bamboo close to his house and it took a bulldozer to get rid of it. I know a guy who split some large bamboo stalks lengthwise and made rain gutters out of them! As for the ivy, yes it adheres to brick and will invade tiniest cracks and windows. Unless you are willing to dig up the ivy roots, you will need some type of strong weed killer. Now back to the antenna - it's amazing just how well even a most simple antenna will work. That is why I have always enjoyed making wire antennas. Have fun with your antenna.
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by W9IQ on February 23, 2019 Mail this to a friend!
For your ivy problem, use Tordon RTU (ready to use). It comes in a one quart squeeze bottle. Cut the ivy plant near the ground and apply the Tordon to the freshly exposed cut stump surface, particularly in the cambium area next to the bark. This very selective treatment will kill the roots.
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by K6CRC on February 24, 2019 Mail this to a friend!
Great story, great ham spirit.
Some of us have to work with yards, neighbors, and spouses to get a usable antenna system up.
 
An Inexpensive and Effective 20-Meter Vertical Reply
by KD8ZM on February 24, 2019 Mail this to a friend!
Even in Ohio, bamboo is very invasive. I have it planted on an island out back, as it can't spread underwater, so it is contained. The cold weather doesn't stop it one bit. In fact, the bamboo I planted, I obtained from Massachusetts!
Brady kd8zm
 
RE: An Inexpensive and Effective 20-Meter Vertical Reply
by KJ4DGE on March 4, 2019 Mail this to a friend!
As nasty to have growing in a yard, the cut bamboo holds the test of time as a mast. We have had 35 to 55 MPH gusts here in Leesburg VA and all 4 masts I have alongside the house are still standing. Perhaps due to the flex and lightweight of the material and some good guying on my part.
 
An Inexpensive and Effective 20-Meter Vertical Reply
by N5LB on March 8, 2019 Mail this to a friend!
Well done. I have had great times with a vertical on 20.
 
An Inexpensive and Effective 20-Meter Vertical Reply
by KA0USE on March 21, 2019 Mail this to a friend!
bamboo! this is waaaay too cool!
 
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