Thursday, 20 September 2012

St. Louis Vertical Part 3, Conclusion

© Bob Baillargeon St. Louis Vertical-3593

This is part three, the conclusion of the construction of the St. Louis vertical.

I terminated each end of the twin lead by melting a small hole in between each conductor, large enough to fit a zip tie through and pulled in nice and tight. Then I stripped off insulation from each conductor and soldered them together – did this at each end of the twin lead coil. The bottom shorted conductor is kept bare and I use a good quality alligator clip to attach my coax center conductor. The orange wire is attached to a 17 1/2 foot counterpoise as seen below.

© Bob Baillargeon St. Louis Vertical-3585

© Bob Baillargeon St. Louis Vertical-3587

Here you can see the bright orange stake that I use in the field, along with the bright orange counterpoise so nobody trips over any of this stuff while operating portable.

Using alligator clips allows the use of multiple sized counterpoises to increase the efficiency of the St. Louis vertical while in use.

I carry a second stake with a 40 foot counterpoise. In this configuration the antenna resonates around 6.5Mhz. In a future version of this antenna I’ll add fewer turns of twin lead so it resonates close to 20 meters. I use an LDG tuner, the QRP Z11 along with my FT-817 and the tuner handles this antenna quite nicely.

© Bob Baillargeon St. Louis Vertical-3588

The photo above shows the upper terminated connection with a male/female connector to attach the radiating element that extends to the tip of the Wonderpole. It provides an easy disconnect point for the radiating element.

© Bob Baillargeon St. Louis Vertical-3595


These male/female connectors are available at most hardware stores that carry electrical supplies. I use heat shrink tubing to give all the connections a professional look and I think it extends the life of the antenna components. It doesn’t take long to add that extra finishing touch.






The antenna is staked on a ground spike used for beach umbrellas. It is a discontinued item that was available at Lee Valley Tools here in Ottawa. I attach a one inch wooden dowel about 3 – 4 feet long and to that I attach the St. Louis Vertical with large plastic zip ties. At the end of my session I just snip the zip ties off. The zip ties get the Wonderpole nice and snug against the non-reactive wooden dowel and if need be I can hammer some of the extra length of the wooden dowel into the ground for greater stability during windy conditions. I sharpened the end of the dowel for ease of insertion.




© Bob Baillargeon St. Louis Vertical-3589

Here’s the St. Louis Vertical fully extended at the edge of my patio. This antenna is a great portable addition to operating in the field and it sets up in less than five minutes. My first contact was on 15 meters using 2 watts on PSK31 to a station in Slovenia with a 599 signal report.

Please let me know if you have any questions of the construction details.

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