St. Louis Vertical Part 3, Conclusion

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.

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.

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.

 

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.

 

 

 

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.

St. Louis Vertical Part 2 of 3

This article is part 2 of the construction of the St. Louis Vertical – a continuation of part 1 that I published a couple of years ago. You can head over to part 1 of the construction article here.

Continuing from grinding down the Wonderpole clips I further grind them down with the Dremel tool so they are flush with the tube; this will allow the twin lead to lay flat along the body and also allow the adhesive to better cover the tubular shape of the Wonderpole.

The next step caused me to think very carefully on how to wrap the twin-lead onto the Wonderpole. I had read on various sites describing how hard this was going to be. Some described it as a two man operation to ensure that the twin-lead was wrapped tightly around the pole. Hmmm, this was going to be a problem unless I figured an easy method to accomplish this task. Of course thinking about these last two years I finally came up with a solution. Enter some 3M Indoor/Outdoor carpet tape. Man this stuff was sticky but I think it would hold and as it turned out was an elegant solution.

The trick was to apply the tape every inch or so, keeping the backing on until I reached the next inch while turning, by hand, the twin-lead. This was hard work and each time I stopped to rest my aching hands I attached a zip tie to hold the stiff twin-lead in place. Eventually I surmised that additional tape was needed so I eventually covered the entire length of the pole as I wound the twin-lead.

There was still a problem – the stiff twin-lead was pulling away despite the extreme stickiness of the 3M tape. Thinking quickly now as I was at least two hours into winding this twin-lead on the pole. I went to my workbench in the garage where I do the occasional refinishing work on antiques. I use a Black & Decker heat gun to lift old paint from projects I’m working on. I figured if I heated the twin-lead sufficiently it would take on the cylindrical shape of the pole – an it did – it worked great, though I kept the zip ties on just in case.

 

You can see my progress in the photo below. The white tape backing is removed to expose the sticky backside of the tape; and you can see the zip tie in place while I rest my hands for awhile.

I had a good supply of RCA twin-lead that I had purchased about 10 years ago at Princess Auto, a surplus type store located across Canada. Of course halfway through construction I had neglected to figure out how much of the 50 foot length of twin-lead I needed. A quick calculation of number of turn per inch showed that I would have almost five feet left over. That horseshoe was working overtime now…with this important information in hand I continued winding until I reached the end of the pole. I still have a 50 foot length and a 100 foot length set aside for other projects using twin-lead.

 

 

 

 

The picture at the left shows detail of the zip tie and the double sided tape exposed for winding. Every few inches I would fire up the heat gun to meld the twin-lead to the pole shape.

After almost three hours I had completed the toughest part of constructing a St. Louis Vertical and took a good rest before continuing this homebrew antenna.

Part 3 to follow tomorrow.

Here We Are, Again

Here’s my first blog post in a good long while. I figured it was time to get things going again and this post will be about some current projects here at VE3MPG.

A station photo is in order now that the shack is clean and tidy (somewhat). This varies day to day, hour to hour.


I’m located in part of the basement called the “bunker” – 2 windows, one facing due south the other to the east so I get some nice sunlight most days even during the winter months. Power to the station is supplied by a dedicated 120V line and a second, share 120V line. Both have APC uninterruptible power supplies to condition and smooth the AC coming into the shack. In the event of low voltage or complete loss of power the APC units shut down the computers gracefully and a small utility lets me monitor line voltage and power interruptions. The APC units prevent power surges from reaching my equipment, but a good ground is necessary.

The next posting will be about Part II of the St. Louis Vertical article from April 2010. Hope to be completed with testing and construction in time for the annual Chilicon qrp outing at the Rideau River Campground on September 14th and 15th sponsored by the Ottawa Valley QRP Society.

That's it for now.

St. Louis Vertical Part 1 - Prep

The St. Louis Vertical portable antenna has been talked about and modified over the years. It’s a very portable antenna solution for Field Day or QRP enthusiasts. It’s easy to build and modify and covers 40 meters to 10 meters with the use of a tuner. Radials are a must with this type of antenna. I use a Shakespeare Wonderpole, a collapsible fishing pole. Fully extended it’s 20 feet long and collapses to 45 inches for storage and transport.

Years ago I purchased a good amount of Radio Shack twin lead for this project and like any good ham I’m finally getting around to building a St. Louis vertical for use at Field Day and with the Ottawa Valley QRP Society group outings.

The first preparation that must be done on the Wonderpole is the removal of the two clips midway up on the first section. These two brass clips are used to hold a fishing reel. The reason for removing these two clips is to assure that the twinlead once wound on the lower section is flat against the bottom section when you wind it on. It’s more esthetics and it makes it easier to wind without the bumps of the clips underneath the twinlead.

I used a Dremel tool with a cutting disk attached to cut through the clips. I still have to smooth down the plastic adhesive used to attach the clips with a small grinding tool attachment on the Dremel.

For the last while I’ve been thinking quite hard to determine a good way to wind the twinlead onto the bottom section so it stays in place. In part 2 of this series I’ll show you a novel method that I devised to accomplish this – it’s weatherproof too.

Have been listening to 17m psk this afternoon and just finished working A71EM in Qatar with 40 watts on the R6000 vertical. 17 is a fine band with some great DX and quiet band conditions – opportune for working DX. It seems to be open early morning till sundown here near Ottawa – always with some exotic stations waiting to be worked.

Here’s a link from the American QRP Club describing the St. Louis Vertical:

AMQRP.ORG St. Louis Vertical