Review of DX Engineering’s 6BTV 17 Meter add on kit

Overview:

Over the past few years I have been using a Hustler 6BTV vertical antenna as my primary antenna for 80, 40, 30, 20, 15, and 10 Meters.  The antenna has worked very well for me, and I have worked much DX with it.  Over the years I have spent a great deal of time getting things tuned as I want them, putting a large, (40 radials), radial field in place, and getting the antenna exactly the way I want it.

I have been using a BWD-90 for 60, 17, and 12 meters.  The BWD-90 is basically a Dummy Load you suspend in the air, then feed it power.  Some of that power leaks out and is radiated, the rest goes up as heat.  The BWD-90 is about 6 db down from a dipole performance wise.  You might ask yourself why in the world would anyone use a BWD-90?  The answer is it is flat across the 3-30 MHz., spectrum at under 2:1 SWR.

As you can guess, the BWD-90 is not a  stellar performer, but it will load on almost any frequency.  I have been on a station simplification quest now for a few years, removing equipment where I can, and in general reducing the complexity of my station.

Part of that quest was to try DX Engineering’s DXE-A0KB-17M-INS 0c, 17 meter add on kit for the Hustler 6BTV.  I have had a lot of trepidation with regards to making any change to the 6BTV, as it is working very well, and I want it to continue that way.  I have literally spent years, tuning and setting this antenna and its associated radial field up.  As a result of all that work, and time spent, I don’t want anything to mess with the performance of the 6BTV.  I was quite worried about what would happen to the antennas performance if I added the kit.

Kit arrival, and rational for purchase:

DX Engineering 17 Meter add on kit

My initial idea was to do the cheap ham thing and build this kit from scratch.  I did the numbers, and to build a 17 meter add on right, would cost almost the same as purchasing this kit.  On top of that, I would not be using cut aluminum, but PVC as spacers, PVC I would have to paint to protect from UV, you get the idea, lots of little things that can and will go wrong over time.  So I decided to not be a cheap Ham, and ordered the kit from DX Engineering.

Given I am going to be feeding the output of my Elecraft KPA500 amplifier into this antenna, I want nothing to go wrong, ever, not even once!  So I decided to spend the bucks and get the kit as it looks far better built than anything I could cobble together.

I ordered the kit from DX Engineering online, on February 27th, 2020.  It seems they are the only ones selling this item commercially.  It arrived March 3rd, 2020, a few days prior to when I was told it would arrive.  It arrived in a heavy duty box, very much larger than I expected.  It was well packed, and the box successfully protected the contents from the ravages of the transport agent.  The smaller box you see the left, is the actual kit box from inside the shipping box.  DX Engineering double boxed this item.  Something you don’t see much anymore.  The first thing I did was to tear into the box, and read the instructions.  After reading them from cover to cover, I decided to build the kit in modules, inside my home, where it was warm, and dry.  First the lower mounting point, then the upper, and coil.  I spent about an hour looking over the parts, and gathering all the needed materials.

DX Engineering recommends some sort of copper based compound, called “Jet-Lube” to assist in getting the aluminum surfaces to contact each other electrically, and as an anti-seizing agent.  I dislike the ionic difference between AL and CU, so I use a compound called Pentrox-A, which uses Zinc as the active ingredient, a much lower ionic potential exists between aluminum and zinc, so less corrosion over time.  This is not to say that the compound DX Engineering recommends is wrong, or does not work, just that I used Pentrox-A, and have for decades, and have had zero issues with it.  So I used Pentrox-A, as opposed to the Copper compound DX Engineering recommends.

17 Meter Add on kit contents.  Click for larger.

I unpacked the smaller box, and found only a small number of individual items, see photo to the left.  The upper coil support consists of the long straight aluminum piece, and the T shaped black insulator.  Click any image to expand it.

The lower wire support, and connection point is the triangular shaped aluminum piece visible in the center of the photo.  It is cut precisely, and in general well built.  There is a parts kit that comes with four bags of many, many small parts.  The photo is deceptively simple looking, there are a LOT of parts to this kit, and 75% of them are small, and in those little plastic bags you see on the left.

All items are custom cut, and all items fit together exactly as they should.  Nothing failed to fit correctly, which is refreshing to see.  The quality of this kit is first rate, and DX Engineering has done a really nice job in putting together a very useful item for 6BTV owners.

I am very happy I purchased this kit, as opposed to cheeping out and using PVC, and non Stainless Steel parts.  An example of the care DX Engineering puts into this kit can be seen on the long straight aluminum piece, just to the left of the lower mount point.  If you look closely you will see a section around the screw hole that is just a bit more shiny than the rest of the piece.  That shiny spot is caused by someone at DX Engineering using a scotch bright pad to shine up the aluminum to facilitate making good electrical contact.  I found several of these spots where someone had taken the time to actually, by hand, shine up the aluminum, removing the aluminium oxide to make better contact!  This level of workmanship is rare in today’s world.  Bravo to DX Engineering for their workmanship!

Assembly:

Part of upper arm standoff

DX Engineering provides a very nice manual, both with the kit, and as a PDF file online.  I always download the manual if possible prior to purchasing a product, and I did so with this item as well.  Nothing in the manual scared me, in fact, some of the steps and comments led me to believe, (correctly), that this kit was reviewed, and used by someone at DX Engineering who actually knew what they were doing!  Things like including a scouring pad, and instructions to shine up the aluminum, prior to connecting parts, goes a long way to convince me that someone who knows what they are doing wrote this manual.  All in all, this kit is well thought out, simple to build, and very well documented.

First things first, I decided to build as much of the antenna inside as possible, then stage it outside for final installation and testing.  First I built the lower wire mounting point, then added the wire, and spring, followed by the upper mounting point.

The antenna went to together rather well, with a few notable exceptions.  I was at a bit lost as some of the diagrams showing the screw layouts, could have been a bit larger.  With the aging Amateur Radio population, I am a bit surprised at how small some of the drawings were.  But, my trusty head mounted magnifiers came to the rescue.

In any case, I finished building both the upper and lower support arms, found I had some “extra” parts, then left them for the night, with the intent of returning in the morning and rechecking things…

First thing the next morning, I called DX Engineering, and asked if they sent “extra” parts as a rule.  The person said nope…  OK, back to rechecking every screw connection for parts count, and type…  I found a few small errors, but overall, not many.  I had a rather large number of parts left over, so I chalked it up to extra parts…  Every screw and joint was checked, so I suspect a bag of extra parts were included in error.  Hope I am right!

As an aside, look at the image of the upper stand off arm, notice the scrubbed area around the nut?  Again, DX Engineering did that, not me…  This is a testament to how well thought out this kit is.  The dark smudge is Pentrox-A.

Square peg, round hole.

There were a few points where I had to recheck things…  One interesting item was the keyed carriage bolt used on the black insulator material used in the upper wire support arm.  The hole was round, and the key on the bolt was square, yes– DX Engineering is asking you to put a square peg in a round hole.

My first thought was that I must be using the wrong bolt, so I looked at the instructions again to be sure…  Seeing the diagram at the left, told me yes, that was OK…  So I lightly tightened the nut, low and behold, the square peg sunk right into the material used as an insulator.  After seeing that, I was very careful to not over tighten anything going through the black plastic material.  I did tighten everything that was metal to metal very tight, and if it conducted current, it got Pentrox-A as well.

Overall that was the only real question I had during the build portion of this process.  The kit went together well, the instructions were clear for the most part, and in general, once built, things looked well designed.  I am glad I spent the few dollars extra to get a professionally constructed kit of parts, as opposed to hacking it together using PVC, and SS parts from teh local hardware store.  I spent a lot of money on my KPA500 solid state amp, and having to send it back to Elecraft is not something I want to do, so all in all, I think it cost me twenty bucks more than if I had built everything from new parts.  A small price to pay, when compaired to sending an amp back to its maker for repairs…

Here are a few photos of the various items that come with the kit.

Mounting and testing:

AA-600 by Rig Expert

As I mentioned upthread, I was very worried that this kit would detune my already carefully setup, and tuned 6BTV.  Prior to mounting the kit on the 6BTV I took a set of measurements using my AA-600 analyzer from Rig Expert.  I took a full set of measurements, both at the feedpoint of the system, and at the radio end of things.  The AA-600 is a wonderful instrument, couple it with a Laptop, and it will give you a lot of information on an antenna system, things like return loss, SWR, Smith charts, etc.  I started with an AA-54, and slowly worked my way up to the AA-600.  At no point have I been sorry I purchased this device…  I will be reviewing it later this year…

After hauling all the tools needed outside to measure things, I sat down and took a set of measurements prior to install.  Next I installed the kit, it went on simply enough.  The only issue I see is in the drawings in the assembly manual it shows the pipe clamps as not covering the yellow sticker at the base of the antenna, while in reality half of one pipe clamp is insulated from the antenna vertical element by that yellow sticker!  This caused no issues however.

Scotch-bright pad.

I used the included scrub pad to buff up all connecting surfaces, then added liberal amounts of Pentrox-A to all mating surfaces that carried current.

If you look at the metal part in the upper right of the photo of the scrub pad you will see that DX Engineering scuffed the surface to make sure that connection happened…  This is actually very important as aluminum forms a coating of aluminum oxide almost instantly, which can insulate aluminum parts from one another.  I am very impressed with the level of thought that has gone into this kit.  Little things like this make it a pleasure to build, and insure it will work when finished.

Pentrox-A keeps O2 out of the connection, so hopefully there will not be an issue later.  In any case, the pad works very well, and took off all the accumulated crud of several years of sitting in the Oregon rain.  The vertical element was once again bright and shinny, even if only for a short time.  The rains will return next October.  I hope to do a weather proof to the antenna just before Winter sets in here in rainy, wet, Oregon.

The test results were as follows for the Pre and post install of the kit:

80-10 meters prior to kit install.  Click for larger.

80-10 meters post kit install.  Click for larger.

As you can see, almost no change in the other bands, just the addition of the new SWR dip in the center of the 17 meter band.  Tuning was easy, just slide the little antenna ends in or out some, take a reading, and you are done.  I was able to move the SWR dip anywhere I wanted in the 17 meter band.  It is after all a very small band.  Here are some closeups of a few bands, pre and post kit install:

80 Meters pre kit install.  Click for larger.

80 Meters post kit install.  Click for larger.

As can be seen, 80 slipped up slightly, which in my case was fine, I was a bit low on 80 anyway…

40 Meters pre kit install.  Click for larger.

40 Meters post kit install.  Click for larger.

As can be seen, 40 did not change at all!  Given 40 is my favorite band, this made me very happy…

The test setup looked like this:

Feedpoint testing, click for larger.

The Pelican case is used to store and transport the AA-600, and a Bird watt meter.  On top of the Pelican case you can see the Scotch 130 tape, and the Scotch 33 tape I used to perform weatherproofing on the final connections.  Once I removed the scotch tape  items, the Pelican case makes a fine seat to keep me out of the wet grass.

The Laptop is a Windows, XP machine that never touches the Internet for any reason, all it does is work with the AA-600.  The rest of the items are there to assist in the measurement phase of this process.

The Makita power screwdriver was used to screw in and out the hose clamps, and it was set to not strip them.  Setting 1.  I have stripped out these types of clamps before, and finding one with a stud on it, and stainless steel in town would prove to be difficult, so I was very careful to not wreck them with the electric driver.

I used the power tool only to take up slack in each screw clamp.  I then hand tightened each one.  I applied Pentrox-A to each contact point that carried current, after shining them up using the included scotch bright pad.  I then clamped them on the vertical part of the antenna.

Before and afters for each band.  Before is on the left, after is on the right, click any image to enlarge:

80-10 meters, before is to the left, after to the right.

80 meters, before is to the left, after to the right.

40 meters, before is to the left, after to the right.

30 meters, before is to the left, after to the right.

20 meters, before is to the left, after to the right.

17 meters, before is to the left, after to the right.

15 meters, before is to the left, after to the right.

12 meters, before is to the left, after to the right.

10 meters, before is to the left, after to the right.

04/10/20:

I have had the kit in place now for a month now…  I am more than happy with the performance of this add on.  It is performing far better than my reference antenna, and better than a dipole at around 25 feet.  I get consistent good signals, and good reports…  The only issue I see–  in the rain the SWR changes.  My normal SWR over sunny dry ground is 1.3:1.  If I operate on a sunny day, and it starts raining, I see the SWR change as follows– the SWR drops from 1.3 to 1:1, then increases to 1:3:1.  This is not an issue for me at all.  I have adjusted the antenna tuning so as to position this dip to center on the band center, that way, it drops, then goes back up, this keeps me in the under 1.5:1 zone.

Click to enlarge

Thanks for taking the time to view this, and feel free to comment on your experiences with the add on kit.