Homemade Full Wave Dual Band Antenna For 2 Meter & 70CM’s Measurements To Make It

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Here are the measurements of the 1/2 inch copper pipe that is needed to build this antenna.

1- 12 inch
2- 2 inch
2- 3 inch
2- 5 7/8 inch
6- 7 1/2 inch
12- Elbows 1/2 inch
1- 1/2 inch PVC TYPE C Conduit Body
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#hamradio
#Antenna

[jkbish]

I followed the instructions. I have been using it for months. If you use 2 meter band, this is a great antenna. I am a bit surprise this antenna is not sold on the web. This is my favorite antenna for 2 meters. I do recommend it.

[jkbish]

I bought the 1/2 inc copper tube. I cut it according to your measurements. I connected it together with aluminum rivets, just like you did. I fashioned the so-239 just like you did. I tried it out today on 2 meters with my Icom T-70A-HD. My receive signal was terrific. I put out some CQ but no one responded. The improvement on received signal was many times greater than my radio's rubber duck.
Thanks for the design.
By the way, all the parts and pieces were not cheap. The main trip to Homedepot cost me about $45. Then I discovered I needed the right screws and I had to purchase a soldering gun (been out of the hobby for a few decades). If I built this at cost, just the parts would best be put at close to $55.

[maufran.nogueira]

I would like to see the antenna in action: swr, gain, range, signal quality ... Thanks for sharing!

[jkbish]

I bought the 1/2 inc copper tube. I cut it according to your measurements. I connected it together with aluminum rivets, just like you did. I fashioned the so-239 just like you did. I tried it out today on 2 meters with my Icom T-70A-HD. My receive signal was terrific. I put out some CQ but no one responded. The improvement on received signal was many times greater than my radio's rubber duck.
Thanks for the design.

[kirkgroeneveld]

Ii built one this week, but soldered all elbows. How do you keep it square all around? Mine doesn't sit level. Also, I showed the finished product to a gathering of Elmers, and they spotted several things on the junction box. First, one claims you should never use gray conduit box, as "it has a metallic element in it that interferes". have you heard this before? 2nd, they recommended mounting the SO-239 on the back wall of the junction box, instead of the lid, so that it is more secure. Do you position it mid-way down the box? I found the ridges or lips inside the cover plate were too narrow to admit the SO-239...and had to cut pieces away for my mounting hardware. 3rd, what gauge wire did you use for the hook-up, and was it sold core, not braided? I was told "The length of your hook-up wire is ALSO part of the length of the antenna." So, keep it short and smaller gauge sold cord wire is better. Last: Why did you not split the difference between the 2" and 3" connector pieces to make all four 2.5" ? Does it make any difference? or are those measurements critical? How do you tune this antenna?

[garystephenson]

nice job I made one of these back in 1990 and work with it may years . WW8O

[davemould]

I will build this and post the output from my nanoVNA which will show impedance, SWR and center frequency. One thing though - when connecting coax direct to a balanced antenna such as this one, you should put a balun immediately before the feed point. I suspect that 1 or two ferrites clipped onto the coax near the feed point would be enough, or wind the coax a couple of turns on a ferrite ring. Otherwise you will have current in the coax shield, and the SWR will change when objects come into proximity with the coax. The NanoVNA is pretty cheap on Amazon, and indispensible for anyone building a homebrew antenna as well as testing commercial antennas (there are a *lot* of fake or rubbish commercially sold antennas).

[graywoulf]

It is an interesting concept but without any information on performance I can't see buying the materials just for an experimental antenna. Do you know of any reviews on this design other than yours?

[frankhovis]

I don't see how this connects to the central heating system. I think it might leak.

[neerptr]

I am sure this antenna would have both horizontal and vertical polarization, good for both FM/repeaters and SSB. But yes SWR is important, really for both rcv and xmt, but more for xmt. I doubt if the antenna has much gain. There have been many VHF and UHF and above antenna designs following similar concept and can work, but must look at what you need. If can tune with tuner if feed is not 50 Ohms at the antenna and mounted on a tower say at 30 ft could be useful, IMHO. But dont expect much performance vs like a 5/8 wave or other typical base antennas, probably not as good as a 1/4 wave vertical, but better than vert for horizontal use. Might be good for satellite use if the satellite signal is strong.

[davidribakoved.c.]

Question. Beautiful Project by the way! In your conduit junction box are you joining the two pieces of copper together, or is there a gap between them? also, how do you deploy it, on a mast? Very clean and neat looking antenna. Is it useful for satellite ops? thank you very much!!

[kbvsb]

Thank you! I can't wait to make a few! I Just finished my second 2 meter cube. I was wondering if anyone had made a Dual band or 70 CM Cube. I am pretty sure this is the Ticket! Thank you for Sharing this !!! 73's kb9vsb, Dwight!

[jkbish]

I see you have offered a design with the copper=Ts. What is the purpose for the in the different design?

[taketwophoto]

How did you tune it? Is there a space or gap inside the LB? Is the LB plastic? ???? Lots of questions.

[jkbish]

i like the rivet idea. I just don't want to sweat the copper. This looks doable

[albertshilton]

THANK YOU FOR THIS VIDEO. However, I’m not sure what decent means. I would also like to see it in action.

[jkbish]

using the pipe measurements the total is 78.75   6.6 feet
calculated
6 feet  11.8 inches   @ 144 mHz
6  feet   9.5 inches @  148 mHz

So, it appears the pipe measurements are a tad short to allow for the 90 degree elbow additional
copper. Wonder if this is correct?
*IF* I am, then I will just cut each piece about a half inch longer so it fits into the 90 elbow.
Does that make sense?

[chrissmart]

Could someone adjust these measurements for 222-225 mHz? I'm urging people in my local club to build something for that band. thanks!

[neerptr]

I do with the video had more testing shown. Essentially all we have is photos of what is called an antenna. But good to see some working on building things. I wonder if there is a name for this antenna so we could google and look up giving more detail.

[glockipsc]

Kind of dark, but inside the conduit box.... is looks like the two vertical pieces are split and not touching. Is there a certain distance that needs to be maintained between the two? Is this where the tuning occurs, or is that done by changing the length/height or the lower verticals? I'm in a restrictive HOA, and this looks like a great piece of "decorative art" to put on the back porch. :) And, I'm guessing on the feed line: the center wire attached to the top vertical, and the shield attached to the lower vertical? Thanks in advance, and it looks great!!!