The Stake Stick Vertical
The St. Louis Vertical, widely known as the SLV, is a great all band vertical antenna for portable use. I was interested in something a bit more compact that was optimized for the higher bands. The SLV works well on 40 meters, but can be finicky on some of the higher bands as its 20 foot total height becomes a difficult electrical length.
Originally I designed a custom wire for the SLV that was just the right length for 20 meters and used a modified alligator clip on the top to "swallow" a short stainless steel whip. Sliding this in and out provided tuning. Still this was a lot of antenna for just backpacking and I was concerned about the material the SLV pole is made from. I wanted something a bit cleaner, self supporting and optimized for the higher bands. In Hawaii, portable operation works best with 20 and above, especially 15 meters.
I started with a CB antenna mounting from Radio Shack. This has a heavy aluminum L-shaped bracket that has a PL259 connector on one side, and a 3/8 inch standard mobile mast fitting on the other. Hustler whips, among others, screw right into this fitting. The bracket easily clamps onto a 1/2 inch aluminum rod. One intended application was to clamp onto the large mirror supports on big truck cabs to hold 4 foot helical CB antennas.
The idea was that an 18 inch long, 1/2 inch diameter aluminum rod pointed on one end could be clamped into this fitting. When shoved into the ground, this aluminum "stake" would support the antenna and be the beginnings of a ground system. True it was not much of a ground rod, but it would bleed off wind-generated static and provide some initial ground return contact.
A spring also from Radio Shack was added to the fitting. For a reasonable ground I went according to the basic design criteria that radials do not need to be resonant if used to supplement ground conductivity, only numerous. Originally two bundles of 8 radials, each 10 feet long, were fastened under the same bolts that clamped the bracket to the aluminum stake. To prevent any nonsense from the coil spring, it was shorted around by a length of 1/4 inch braid to ensure it was not acting as any electrical base coil.
In its first design the Stake Stick was used with a standard single piece Hustler mast and two interchangeable Super Resonators, one for 40 meters and one for 15 meters to give two band operation. It naturally worked better on 15 meters than on 40 meters. Both the SLV and this version of the Stake Stick were used during the first trip to the botanical park campsite during QRPTTRF. Compared to the magnum SLV, the SS was significantly less useful on 40 meters as might be expected, with its total height 7 feet vs. 26 feet for the Magnum SLV. Switching back and forth between the two antennas indicated from 3 to 5 Db difference in received signal levels on 40 meters.This photo shows the minimal 40 meter Stake Stick format with just one Hustler pole and one of the big "Beer Can" magnum 40 meter coils. A better version can be created using longer pole segments to increase radiator length below the coil and retuning the coil.
But, 40 meters was not really the objective of this antenna. The Magnum SLV is portable and much better suited to bands like 80 and especially 40 meters where it approaches a full 1/4 wave tall. Also the Hustler resonators, even the large beer-can sized Super Resonators, very sharply limit the bandwidth of the antenna while causing coil losses.
After looking at Hustler parts for a while, I guessed that a SS whip sold by Radio Shack that is 39 inches long would fit in the collet of a standard Hustler resonator. I took a 10 meter resonator and band sawed out the insulator and coil. I cleaned up the two cups, the one which holds the fitting that screws on the top of the Hustler mast, and the one which holds the whip mounting, with collet. A piece of 3/8 inch copper pipe six inches long was soldered between these two, replacing the insulator and coil with essentially a six inch, zero turn "coil".
Now the Hustler standard mast, the mounting, the 14 inches of the adapted "resonator" and the 39 inch whip added up to an adjustable length that covered the 10 meter band with a full size, 1/4 wave vertical element. The bandwidth compared to even the 10 meter Hustler coil was astounding. Also the SWR minimum was very satisfactory, dropping below 1.4:1 easily, even with a limited ground radial system.
When a fitting to allow end coupling of masts was added, two of the Hustler 54-inch masts could be mounted end to end. The 14 inch, zero turn coil "resonator" and a very short 9 inch whip, added to this pair of Hustler masts resulted in an adjustable length appropriate for the 15 meter band. It also was extremely broad banded, thanks to its full size quarter wave dimensions. It tuned to an even better SWR minimum. There was a slight advantage to tuning this antenna either for SSB or CW given the very large size of the 15 meter band, but it was broad banded enough to be tuned to a compromise frequency like 21.175 and still cover the entire band without further help from an external tuner.
When the same setup used the 39 inch whip instead of the 9 inch whip, it came out to a full size, tunable element on 17 meters. This one also tuned to a very pleasing SWR below 1.3:1. All of these were tested on flat moist ground over the ground radial system described below. They were well clear of trees etc. at least by the diameter of the circle of radials. The feedline used was 30 feet of RG/8 coax.
The ground system on the second version was improved by addition of a 12 inch aluminum plate onto which four sets of radials were mounted. The two sets of 8 radials each 10 feet long, plus two new sets of radials, of six wires each, each wire 13.5 feet long. This made a total of 28 radials. The aluminum plate can be marked with quadrant lines to assist in the laying out of the radials in a nice even pattern. The radials were not mounted at the edge, but at least a few inches back from the edge of the disk which covered the gaps in the individual sets of radials and made for a very nice "electrical" presentation near the base of the antenna.
A right angle PL259 adapter was also added to "bend" the connection at the base outward instead of downward for ease of attaching the feedline. This really helps by preventing a sharp turn on the coax at the base of the antenna, and allows the fitting to be easily pushed down right onto the aluminum plate without concern for leaving room for the coax to "turn the corner" under the fitting.
The bonus on this antenna was the use of a 17 meter standard Hustler resonator and the 36 inch whip on top of the two Hustler masts joined end to end. It resonates very well in the 20 meter band with a large increase in bandwidth vs. the single mast and 20 meter resonator version. The extra height plus the considerably reduced coil size makes quite a difference. A very low SWR was possible with enough bandwidth to comfortably cover the SSB or the CW portions of the band, however, retuning was still worthwhile for these two ranges. Trying to find a compromise setting to cover the entire 20 meter band resulted in SWR's rising uncomfortably high at the band edges.
These tests were made during QRPTTF, during which we made a return visit to the park site with both an improved magnum SLV and the improved Stake Stick. The magnum SLV now used a large radial system and a modified VersaTuner as a base matching network, with no coil on the pole, just a heavy braid element 26 feet tall. The SLV setup like this was very close to a 5/8 wave vertical on 15 meter. The magnum SLV showed some better reception on 15 meters, but virtually no difference on 17 meters compared to the Stake Stick. Due to the bad band conditions no contacts were made on 10 meters, unfortunately.
It appears the two Hustler masts by themselves are just right for 12 meters. They will not tune of course, but should be quite broad banded. Testing on this was unfortunately skipped last time out and needs to be done yet. One Hustler mast resonates about 49 Mhz. It may be broad banded enough to work on the bottom of the six meter band depending on how understanding the rig is. I also need to measure its exact resonance when mounted on the spring/base and see what SWR is possible on six and 12 meters with one and two masts by themselves.
Stake Stick 20,17,15,12?,10 Meter Antenna Parts List:
Some of the parts for the Stake Stick, including the mounting with spring, the Hustler 17 meter standard resonator, the modified 10 meter resonator with its copper pipe replacement for the coil assembly, and the end to end coupler for the masts. Below the modified 10 meter "resonator" is the stake which is used. One of the whips is only a bit longer than the photograph, the bottom one is a full 36 inches long. The spring proved impractical and was replaced with a much beefier spring which also proved impractical on a full /14 wave 20 meter version. Finally, the spring was abandoned all together.
The aluminum plate fits into the backpack as a "back plate". The 18 inch stake rod, the two masts, the 17 meter resonator, the special modified "resonator", the short and long whip, all bundle into a small fishing rod carry case. The mounting and the four coils of radials slip into the backpack side pockets.
A compact screwdriver and two selected wrenches are useful to set it up. One can get by with your Leatherman tool, but a tiny open end wrench just the right size to open and close the collet on the whip mounting, is a real pleasure. A second wrench for the base bolts finishes the tool set. If you look around you can find a wrench with a smaller size on the other end, and can match the bolts holding the radials to the aluminum plate to that same size.
A three-foot diameter loop of rope is the best tool for extracting the supporting stake and mounting from the ground. You can slip the rope over the mounting, brace against your knees as you squat down and use the full power of your legs to lift up. Done correctly this method slides the stake right out of the ground. I have seldom found a hammer necessary to drive the stake, I usually just step on it to shove it into the soil.
It is helpful to attach one of the masts before you start driving or shoving the stake into the ground. It greatly assists with getting the mounting vertical. The ground radial connecting plate is placed on the ground and the stake is shoved through a central hole until the mounting is flush against it, all the way down. A short jumper of 1/4 inch braid connects the mounting from one of its bolts to the plate/radial system.
Setup is rather fast and spreading out the radials on the ground is not as bad as you would think after a few times. They are stranded, insulated 24 gauge wire. They do quite well just being pulled out straight and laid on the ground. With the right wire, it will lay pretty much where you put it, reasonably straight.
Neatness counts, but only up to a point. At one time I was using hairpins pushed down over each radial about four inches from the end to secure them, nice and chalk line straight, bruising the daylights out of the tip of my thumb pushing them all in. The last time out, I decided to just pull the radials out straight, lay them down and say "good enough". It worked very well and cut the hassle of setup in half.
If you are used to tuning Hustler whips, you know all about tiny moves of the whips, a 1/4 inch or 1/8th inch at a time. With this system the moves are more like one or two inches at a time. Without the coil, tuning is far less critical and the SWR dip quite broad and mellow. Even the 20 meter version tunes in 1/2 inch increments.
The center stake serves well to provide a static ground reference for the antenna system. I would still not want to be around if this thing got hit by lightning. The feedline should probably be longer than the radials so the rig can be setup just outside the radial circle. I have used lengths from 18 feet to 30 feet. Feedline length is not at all critical.
The bandwidth is wonderful, the SWR on all bands tested is quite good. It should be possible to tune this by just measuring the length of the whip extended and get close enough to use without a tuner, even for the 20 meter version.
Since on 17,15 and 10 The Stake Stick is a no-compromise, full size 1/4 wave radiator with adequate ground, performance should be expected to be good. Field testing so far indicates it works very well. The 20 meter version only uses a small loading coil and is about 13 feet tall and loaded well above center. It is one of the few cases where retuning is worthwhile going from CW to SSB portions of the band. But even here, the difference in bandwidth vs. a standard Hustler mobile whip setup for 20 meters is remarkable.
The entire thing is light and sets up very fast, except for the fiddly bit with the radials. It takes down quite fast as well. The radials just roll up. I am still looking for the most compact case for the various parts such as the two Hustler masts. I have come up with something that can be used as a somewhat fat walking stick, with the parts inside. It is made from 1.25 inch PVC. It works rather well. Remember that for air transport such a case needs an air pressure relief hole. It need not be big, just present. I have a 1/16th inch hole in one of the pipe caps used to close the case.
The modified 10 meter resonator can be used as is for a 10 meter mobile antenna with an immediate improvement in bandwidth over the 10 meter coil it started life as. The total Hustler height will be greater, but not by much.
The versions using multiple masts can be installed when the vehicle is parked to increase efficiency of the mobile antenna system on 15,17 and 20 meters. It is a simple matter to screw on the additional mast/joiner and the appropriate version of the "resonator" and whip. The results will be much better than using one of the Hustler Super Resonators. The brave of heart might even try using the combination while mobile, with appropriate fishing line guy wires as is common for big whips.
For those who use a Hustler whip while mobile on an RV, this modification makes for a simple yet more efficient setup for 20,17 and 15 meters when parked at the campground without any dragging of wires, assaulting of trees with wires, etc. When parked, you can clamp on a simple counterpoise to lay on the ground to enhance radiation further. Bumper mounting makes for a very asymmetrical counterpoise. Running a counterpoise wire of the correct length in the opposite direction will balance things out quite a bit.
20 meters 19 feet 5 inches 17 meters 15 feet 2 inches 15 meters 13 feet 10 meters 9 feet 8 inches
By use of a heavier duty spring and a special adaptor which "stretches" the coupler by adding 36 inches between the two threaded 3/8 inch adapters, it is possible to obtain a full size vertical on 20 meters with no coils. This unit has been tested with good results. The coupler joints on each end make this assembled coupler a total of 38 inches long. This is more than enough to bring 20 meters into capture range of the 36 inch whip "stinger".
A second benefit of this adaptor is that with a shorter whip it can be tuned to a 3/4 wave antenna on six meters. Unfortunately it looks like this may be just a bit too long to make a 12 meter antenna by using a mast, this new longer 38 inch joiner, and the whip holding "resonator". It would work fine if the spring were removed to shorten things to allow for some whip adjustment on 12 meters.
One unforeseen problem with the full size 20 meter version was the spring. It had to be eliminated. When first put up the antenna was working gangbusters. But then I started to have problems. I peeked out of the tent and it was laying flat on the ground! It had fallen and could not get up. The big spring is very very strong, but not strong enough it seems. I eliminated the spring and it worked fine. But I obviously need some small fishing line guy wires to bolster this 17 foot, full size 20 meter version.
But even though 12 meters continues to be a problem, it is minor compared to getting full size operation on 20 meters AND adding six meter operation through use of a 3/4 wave vertical. The 1/4 wave vertical option suffered the same problems as the 12 meter version. The 12 meter version may be just barely too long to allow for any whip tuning.
The 12 meter version should theoretically allow for an inch or two of whip and barely be tunable. It will just have to be field tested next time out. We might get a pleasant surprise. It would be great if such a small collection of parts would handle all of the bands, 20-17-15-12-10-6 meters all tunable, all without coils of any kind, all matching well enough to not need any other tuners to connect directly to a typical rig output.