Steve’s Homebrew Vertical Antenna for POTA

Many thanks to Steve (KM4FLF/VA3FLF) for sharing the following guest post:


A Great Homebrew Vertical Antenna

by Steve (KM4FLF/VA3FLF)

Last spring, I was going through my many boxes of ham “stuff” looking for items to sell at our club tail gate sale. I came across a couple of Hustler SM Series Resonators (20 /40 Meters) that I had acquired. I am not sure where I obtained them, but I decided they were keepers.  That decision turned out to be the first step in a year long process that has given me an awesome homebrew vertical antenna.

After doing a little research I found the resonators and accessories at most of the online ham dealers. They are used primarily as mobile and marine antennas. I had seen where a ham had used these on a ground stake as a portable antenna as well. I ordered a Hustler MO1 mast which is 54 inches tall and thought I would attempt to make a portable POTA antenna.

Antenna base

I had a couple of small aluminum plates that I drilled out a few holes. I cut out a notch to put a SO-239 Stud Mount on the plate as my antenna base. I now had a ground plate, connector, and antenna with resonator. By putting a stake in the bottom of the plate, I was able to get the antenna to stand up. The Hustler resonators have a hex screw for tuning that can be loosened. The antenna can be adjusted for resonance by lengthening or shortening the radiator length. After adjusting the radiator my SWR was still horrible on the two bands.

Antenna base close-up

I had some 14-gauge wire laying around and attached it to the plate using carriage bolts and nuts for my ground radials. I didn’t think about the length of the wires at this point but went with three or four lines around 20 to 30 ft. I was able to use my vertical a few times with moderate success. My SWR on 20 and 40 Meters was around 2:0 to 1 at best. It was bulky and very delicate. Sometimes screwing in or unscrewing the MO1 the SO239 would slide off the edge of the aluminum plate. I put away my contraption for the winter and decided to move on to something else.

In April of this year, I wanted to revisit my project. I identified a few issues that needed to be improved. The main issues with the antenna were bulkiness, took too long to set up, and really had poor performance. I attacked the SO239 problem by drilling out a 5/8 inch hole in the center of the aluminum plate and centered the SO239 mount there. I used an elbow PL259 connector so I could feed the coax under the ground plate insuring the insulator is in the correct position. The shield becomes the ground and then isolates the center connector.

I put some more thought into the ground radials. I needed to find a balance of effectiveness and time it takes to set up the antenna. The rule of thumb is more radials the better until one reaches a certain threshold. I opted to go with four radials, ¼ wavelength for 40 Meters, which I used 32 feet and 6 inches. I assembled PowerPole connectors to the ends of the wire and onto the radials which I made from speaker wire. I found that speaker wire was very flexible and easy to deploy and recover. The PowerPole connectors make the antenna very quick and easy to deploy.

I opted for a shorter carriage bold in the meantime and used four 3 1//2 inch bolts for the feet. I have an open slot for a tent stake if I need more stability in high winds. I purchased Hustler resonators for 10, 15, 30, and 80 Meters. This affords me a full suite of the HF bands. There are two models of resonators. The RM Series is rated for 400 watts. The RMS Series are more expensive. They are rated for 1 KW and have a wider bandwidth. Since I usually work digital or CW, I opted for the RM Series.

Performance

My resonators are tuned for the lower ends of each band staying near the digital portions. My SWR on 40 Meters generally runs 1:2 to 1, and all the other bands do not exceed 1:4 to 1. On 40 Meters the antenna is a bit narrow with SWR above 2:0 to 1 at 7.20 MHz.

The speaker wire is very flexible and combined with the PowerPole connectors, makes deployment quick and easy. I am able to deploy the antenna in five to seven minutes. I still have the military mindset of shoot, move and communicate. I get a kick out of seeing how fast I can get on the air at a new POTA activation.

I always take my 20 and 40 Meter resonators and occasionally will take my 30 Meter. As you can see from the photograph (above), the antenna package can be carried in a backpack with the longest item being the MO1. I will add that Hustler makes the MO2 mast that folds over at 27 inches.  I have not found that necessary for travel.

The PSK Reporter shot is from last POTA activation at Fort Erie National Historic Site. I was using an IC-705 running 5 watts. I was spotted into Hawaii and Europe. I made 21 QSO’s using PSK, FT8 and a couple of SSB on 20 Meters.

This has become my go to antenna. I usually bring my Buddystick Pro and PAR 20/40 End Fed along to my POTA activations. I have not deployed those antennas in the last few activations because I find my Homebrew Vertical easier to setup and it gives me great performance.

I have a couple more things I would like to do to improve my antenna. My next priority is to make some type of hinge system for the feet. This would allow the base to be more compact and easier to carry. This is a work in progress but I am pleased with how my homebrew has performed. If you have any suggestions I would love to hear them.

Thanks,

Steve Riddle

VA3FLF/KM4FLF

11 thoughts on “Steve’s Homebrew Vertical Antenna for POTA”

  1. Thank you so much for sharing this, Steve. It’s funny because I’ve been thinking about some of the antenna parts in my “radio box of forever” back home. I’ve a few cannibalized parts from other antennas and projects and have thought about integrating them into a new portable antenna much like you’ve done.

    Good on you for continuing to improve the design, too. It sounds like not only is your antenna a performer, but it’s also very quick to deploy! Hard to beat that!

    Thanks again!
    Thomas (K4SWL / VY2SW)

  2. Steve, I made a similar plate as well for and center loaded compromise style antenna.

    Hustler is great stuff

    I will now dig through my pile and throw one up for 20m and try some a/b tests

  3. A great post- and a fine use of the Hustler resonators! For those curious about the base plate, DX Engineering carries one with a preformed ‘tab’ for installing an SO-239 connector.

    I have a couple traps left over from a failed multiband 4BTV installation. I learned only later that an elevated multiband feed with those is a recipe for trouble. I found that out for myself, and that included a Genie S-40 rental to avoid the need for raising and lowering the mast. I lowered the lift after each adjustment, but it amounted to a 5-ton steel object in the antenna’s near field. 6 hours and $300 later, I was educated. Doh!

    I should be able to make of those remaining traps. Thanks for an inspiring post, Steve!

  4. Steve, I have a similar setup and have used many times. Mine is a tri-mag mount which already has coax attached. I just use the coax as the counterpoise and haven’t added radials. If it is windy, I just add a rock to the magnet on the windward side.

    Thomas has seen my setup at Crowders Mountain near the parking lot. He may have even taken a photo there too.

  5. The HUSTLER mast resonates on 6 meters. Add the tri band adapter by HUSTLER and three resonators and you have a fantastic four band portable or mobile antenna. I do not use the folding mast because they developed too many problems. The hardware is 3/8” 24 TPI and you will need a few bolts, nuts and lock washers. I often use a truckers mirror mount with a clamp to mount the antenna on any handy grounded metal object. The ground plate and radials are an excellent idea also.

    1. I like that idea. The adapter is 10 bucks at DX Engineering. That would save walking to antenna and swapping resonators. I could load 40, 30 and 20 at one time.

      I will check that our and see how the SWR handles all three. Thanks for the tip!.

      Steve
      KM4FLF

  6. I wonder if this same setup with radials would work with the EleCraft AX1??? It does need something to make it work.

    73, ron, n9ee

  7. I went a slightly different route.

    I have the Hustler antenna, but I mount mine on a tripod (out of the snow and/or mud). I have two radials, 17 feet long, both mate up to a small ‘battery jumper’ clip. The radials are attached to the base of the antenna connector via the clamp.

    Set up tripod, attach antenna, clap the radials and roll them out & secure with small ‘tent pegs’ of the bent wire variety.

    Very fast setup/tear down, flat across ether the CW or phone parts of the band.
    Store in very small space.

    I can use my AS-1320 whip antenna for wideband operation if desired if desired.

  8. With FMJ from Alpha or Chameleon Hybrid and Chineese resonator of 5 meters, It is more easy and versatile

  9. Elevated radials, even 4’ off the ground, would improve the tx efficiency of any vertical by an S-unit or better.

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