WR9R

Sometimes, you just gotta try things..

I have a little issue with antenna-experiment-disorder (aka AED). No matter how many antennas of various forms I try, I still fall into the trap of “could this be better?”

For the last couple of years I have been using the DX-Commander Classic and was very pleased with its performance. It is a great product and I still recommend it. As the summer of 2022 came on, I began reflecting on this installation and considering “could this be better?” Many mock vertical antennas stating that they “perform equally bad in all directions,” but I would call “foul” and say they do not understand the point of using a vertical. There are the obvious benefits of HOA friendly, small space installations, reasonable cost — especially when compared to anything tower-based. I would like to add to the list, low-takeoff angle (good for DX), and omnidirectional.

I use several different antennas — sometimes all at once. A Hex-Beam atop of a tower, dipoles strung on said tower, and an all-band Vertical. This setup allows for a selective arrangement that provides nearly instantaneous switching to find a better transmitting, or more-likely a better receiving advantage. Often during a contest like NAQP, SS, or CWops, I fix the HexBeam west and then switch between antennas to gain the best signal level to my contact-of-interest. I often include a dipole in that selection process to pick up better Midwestern coverage (from here in middle Indiana). So, all that said, I am more about options than I am a firm belief in a particular type of antenna.

So why change from DX Commander to DX Engineering?

The DX Engineering 43-ft Vertical Antenna Package addressed this list. All aluminum construction, random-wire style tuning 80-10M, and a 90 MPH wind tolerance. Another consideration was the simplicity of the mounting base. I nearly took the full-size 80M vertical with a tuner path, but it actually takes a lot more concrete — which is expensive and tedious to prepare — and this aspect alone made it seem cost-prohibitive to me. The 43-foot vertical by comparison, requires only a post-hole and a couple bags of Quikrete.

Radials upon radials..

The DX-Commander–like all quarter-wave antennas–require ground radials. My previous installation had thirty-two 16-foot radials. I used these with the DXE 43-foot Vertical, and added another twenty 32-foot radials to help with 80M performance. These radials were simply stretched out on the ground and fastened down with lawn-staples. After 2-3 weeks I was confident to mow this area again. It is surprising how quickly nature absorbs these radials. When installing radials, I added a little service-length at the ground-plate end. I had to add extensions to the 16-footers to get them to the plate because after a couple of years, nature had drawn them down into the earth and away from the ground-plate. You may have noticed in the photo above that I did not use a DX Engineering Radial Plate, but instead used one from YZ4IZO — I just liked the overall size and mounting of this plate a bit better.

A 4:1 Balun or ATU — That’s the question:

Since some of my motives for this project were educational, I spent a little more money overall in order to best-understand the result. When I ordered the original kit, I bought the package with a 4:1 balun. The balun provides a “friendlier” impedance to the station-ATU than the vertical would provide on its own. With the balun, the ATU can mop-up the difference in matching to effectively tune the antenna system from 80M-10M, but the feedline to the vertical is treated as a net-loss in this conversion. This means that the received signal-level at the radio is less than if it were matched to 50-ohms at the antenna itself. Don’t get me wrong, the vertical with a 4:1 balun is awesome, but I wanted to know how much awesome-sauce I was missing, and in practice would I really notice?

I proceeded to take some measurements of the mop-up in SWR from the 4:1 balun to the station-ATU. The table looks like this:

With my situation, the 60-15M bands are reasonable, with efficiencies greater than 60%. Unless this setup was in a side-by-side comparison with a full-size quarter-wave, one would likely not notice. But when you consider the significance of 3+dB (half the power) being lost, it seems costly. With 6dB reflected as a full S-Unit, I found myself considering the number of times that one S-unit was the difference between making a contact and not. These things matter the most with DXing, contest, and QRP scenarios for sure. If you get on net-operations or like rag-chewing with more localized stations — the balun would make for a more-than-adequate setup.

The trap of “could this be better?”

So after about a month of studying the setup and the losses I decided to invest in my “master’s degree” by upgrading to a remote ATU. Inquiring minds want to know! DX Engineering has an Upgrade Kit that makes the process pretty easy. The ATU is Bias-T powered from the shack over the feedline and is quite smart. Once a band is selected, I simply feed it a 10-15W carrier for a couple of seconds and it tunes right in on the 40-10M bands. (80M can take up to 10 seconds.) Signal levels witnessed at the receiver were appreciably higher, which makes sense because the feed line losses are now negligible. I also found that more metal is better in that this vertical offers a 2-to-3 S-Unit improvement over a Butternut Vertical (which is located a few hundred feet away). Anecdotally, I would say that it performs about 1/2-1 S-Unit over the DX Commander — which is simply a reflection of the differences in physical size.

If there were points of compromise with the resulting system, I would list:

a) 600W maximum power (because I didn’t purchase the 1500W tuner, and I never use more than 600W)

b) 160M really is not possible with this setup (where one can get on 160M with the balun and known sizable losses)

c) 80M has some tough-spots where the tuning may only get to 2:1 SWR — but that can be mopped up at the rig if so desired

**UPDATE (1/7/2023): To improve the 80M tuning (and since my primary use for the vertical is 80-20M) I added some inductance to the base to give the tuner a bit more “electrical length” to work with. This proved to be a solid fix. I did not have any noticeable degradation in the upper bands, but I am sure this will create some losses in the highest bands.

I really like the resulting setup and find it worth the investment. DX Engineering makes some really nice stuff, so I have high confidence in the long-term use of this setup. If you decide this may be a solution for your station, check out the full-tuner-kit; it will save you some money over the step-wise-path that I chose.

I hope you find these ramblings helpful.

73!