It is similar to a Carolina Windom or an Off-Center-Fed design but I really like the radiation pattern that comes from the 10 feet of coax that hangs down from the 4 to 1 balun to a choke or line isolator. I will not rehash the design as it is included in the link above.
I did not make the 4 to 1 Balun as described in the article but rather used one from KI6J. Stu offers them as kits here. Those little kits are hard to beat for price. You can wind Stu's balun to be a 1 to 1, 4 to 1 or 9 to 1. I ordered another one for another linked dipole I am thinking about.
I used BNC connectors that I already had on hand and a piece of PVC pipe that was a shipping container for a whip antenna in its past life. It is 1 inch OD so it fit the washers I planned to use as end caps. I did not have screws and bolts to attached the BNC connectors to the washer so I used brass nails, solder and some glue.
The glue I used throughout the project is JB Weld Plastic Weld and I cannot say enough good things about it. It does require setup time but it secured everything I needed it to, metal and plastic.
|Washers, BNC Connectors and brass nails.|
|Ferrites to be used for the line isolator (12 inches worth)|
|These numbers do not mean much to me but this is what I used|
|RG-58 U used for the line isolator/choke (I used about 14 inches)|
|Washers with the holes drilled out|
|Ferrets and coax going in to the pipe|
|The end connector going together|
|The ends are glued to the pipe|
|The 4 to 1 balun kit|
|add a 25 foot wire and 41 foot wire, 10 feet of coax and a feed line and it is ready to go|
I tried it in the backyard and it worked fine. It is flat on 20 and about 1.7 to 1 on 30 meters and tuned all bands 80 through 6 meters no problem with an Elecraft T1 tuner. Of course the disadvantage is it takes some space to put this thing up. It is heavy at 1 pound 12 ozs and you need to be able to support it. However, on the right summit this thing should work very well.
I hope to get it up to a summit soon. I am positive it will out perform anything I have used in the past. Thanks to K4IWL for the article/design and Stu, KI6J, for the balun kit.
If you plan to make this antenna please check this link as there is some additional information about the design.
UPDATE 16 July 2015: After getting some good advice (see comments) I went back and made a 4 to 1 Voltage Balun using a T106-2 (red) core toroid and 26 bifilar turns of 20 AWG enameled magnet wire. This is different that the original design but is recommended on the link I included above. I have not tried it yet but tested the balun and it seems to be flat at 50 ohms. I will update this entry when I test it.
|Toroid wound and installed|
|The final product|
UPDATE 18 July 2015: I was having all kinds of problems with the 4 to 1 balun in the small tin so I decided to use a pill bottle which did three things. Made it more light weight, gave me more room to work with and finally, it allowed me to attach a rope support and to tie off the antenna wire making it easier to adjust if needed. This helped a lot. I also decided to try David's other suggestion and use a 1 to 1 curruent balun instead of the ferris and coax. This saved a lot of weight and made the overall package much smaller.
|Pill Bottle Balun|
|1 to 1 current Balun|
I strung this up in the backyard and it performed well. I worked a few SOTA stations then decided to test another antenna. More to come.
Thanks David VE7EZM/AF7BZ