That’s not the point though. If we were to cut off the connector we would surely still see a spark from center conductor to shield. If the cable were near station ground I would expect a spark jump. That large a charge has to go somewhere.

The point is a wire, any wire, with wind blowing on it will build a static charge. We should keep this in mind as we design our antenna systems. Including a DC path to ground is prudent.

I cannot imagine a more teachable YouTube moment. Thanks to the poster for making this video available.

Here is a link to a very old video which explains quite nicely what and how static charge occurs…

http://video.google.com/videoplay?docid=2306375174608358801&hl=en#

73

1. Crimp on connectors have been the norm in industry since at least the 1970s. I’m just ashamed it took me so long to figure this out.

This post is very late. The actual date of the events within it are just before March 2009 in preparation for the Virginia QSO Party.

In the many posts within this site, it is no secret my examination of various vertical antenna solutions with comparison between BigIR and the 43 Foot products a big part of this. Check out all the 43 Foot posts on HHD here…

43 Foot Antenna Selected
I chose the DX Engineering 43 Foot quick taper model during the price war between DXE and Zero Five. Compromises understood and simulations complete, I carefully considered the Big IR, but liked the idea of no moving parts or switches at the antenna location.

Back in Black
A bare aluminum antenna would stand out too much in my neighborhood so I decided to paint the antenna black. Priming aluminum is a topic I researched very carefully to be sure I applied a lasting finish. As shown below, I applied regular flat black paint over the primed aluminum pieces except where the pieces slide into each other; If you are going to paint your antenna, you need to mask the mating four or five inches of the lower end of each tube.

Conductive Compound
I used the recommended aluminum conductive anti-oxidant compound suggested by DXE on all physically and electrically mating aluminum surfaces. This results is a gooey mess the first few times you apply, but you get the hang of the proper amount soon.

Antenna Tilt Base – Cumbersome
The “kit” from DX Engineering included an Antenna Tilt Base which I gladly installed. It works great. However, you need to really watch what you are doing when lowering the antenna. If you do not seat the lower pivot bolt properly, you will bind it and/or the top sliding bolt and may simply cut it off.

You are well advised to pay very close attention to what is happening to your tilt base while moving it. If you cannot handle the antenna yourself, enlist the aid of a friend who takes direction well. The good news is you will get the hang of raising and lowering your antenna as you realize you will need to apply some downward pressure during transition.

Basically, you will need to hold the antenna nowhere near its center of gravity and manipulate it just as if it was not attached to anything; You and your two widely spaced hands are the antenna support, not the tilt base pivot point. This ensures you are able to “encourage” the tilt base bolts into the correct slots and keep them there during lowering. The 43 foot antenna is not too heavy, but, in my opinion is very cumbersome due to its length and floppy nature.

Photo Gallery

Radials
You probably noticed only eight or so radials on this 43 foot antenna system. Yes, I know… I need more and plan on installing more soon. On 20 and 40 meters, the feed point impedance is something north of 200 ohms (or something highish). It does not take many radials to create a ground resistance lower than that. However, 60, 80 and 160 meters are a different story. I will add more radials.

Performance – Good enough
With all the simulations I performed in EZNEC…

…I was not expecting more out of this antenna than possible. I knew it would be pointless for 10 and 15 meters. It knew it would provide good results for 20 meters. It would be close to a 1/4 wave 40 meter vertical. It would provide some results on 80 meters. It would stink on 160, yet still provide “something” to use for this difficult band.

In short, it has met all my expectations quite well. I now have one antenna that provides access to the major low sunspot HF bands while sacrificing 15, 12 and 10 meters during this sunspot low. This was the plan for the 2009 Virginia QSO Party and that’s exactly how it worked out.

Comparisons
I had a 75 meter turnstile antenna in addition to this 43 footer during the March 2009 QSO Party. The turnstile out performed the 43 foot vertical in almost every way on 80/75 meters. However, I did use the vertical to pull out one of our roving mobiles about 250 miles away during the QSO Party – I transmitted to him on the turnstile and received on the vertical; I would not have been able to work him without the vertical in the mix. For those wondering, I use the 8 port DX Engineering remote antenna switch – the smaller one – at the end of 240 feet of LMR-400 coax for my ‘antenna yard’ switcher.

40 meters was a bit of a toss up. Most of the time I used the vertical. However, I occasionally tried the 80 meter turnstile on 40 and it did work.

20 meters was tough due to a big DX contest the same weekend as the Virginia QSO Party. I had a tough time competing with the big guns. However, casual operating later revealed the 43 foot vertical does work pretty well on 20 meters.

Attempts at 15 and 10 meter contacts with the vertical are laughable. Zero success, but that’s not a surprise, thus I am not worried about it.

Conclusion
I am very happy to have this antenna. Except for certain times of the year, it is the only HF antenna I have available operating year round. For a single simple antenna (remember no moving parts), it provides at least some coverage on 160-20 meters with best results on 40 and 20 meters. Good enough for the moment.

However…

Those sunspots are coming back and I will lust after a solution for 17-10 meters very soon. My next project will likely be the hex beam as a simple solution for those bands. I will need some kind of support for this antenna which adds to the complexity.

When you compare the steps required to raise even a modest antenna like the hex beam, it is quite obvious no antenna solution will be as simple as the 43 foot vertical even after I took the time to paint it black.

The 43 foot antenna provides, for me at least, a very good value for the money, real-estate and simplicity. I would do it again and humbly suggest it to anyone who needs a single, simple, reliable, stealthy antenna and/or wants an additional “choice” for their antenna farm.

See you on the bands…
73

In particular one member has a magnificent full wave 160 meter loop up around 50 feet or so. He is contemplating using it for NVIS on 80 meters. He desires to lower it to about 15 feet to improve the NVIS characteristics.

It is true lowering a dipole will focus more energy straight up while reducing the energy towards the horizon. This is a tried and true technique on 80 and sometimes 40 meter NVIS and offers a potential added benefit of less sensitivity to far away thunderstorm noise. This is a method of diminishing returns; Lowering the antenna favors the sky more, but the overall gain is reduced. In other words, less signal is focused in a better NVIS favoring pattern.

Full wave loops are quite different as this EZNEC simulation suggests. Here is a simple four sided loop with 128 foot sides and fed near one corner – just like my friend’s 160 meter loop.

It is possible almost any antenna sends a little energy towards the sky for NVIS communications, but to fully take advantage of this capability, your antenna design should flood the sky with energy including straight up. This will ensure all possible angles of refraction/reflection are covered.

It seems clear from this very basic, but perfectly reasonable, EZNEC simulation a full wave 160 meter loop running in the 80 meter band is a good antenna for DX work, but leaves much to be desired for NVIS even if you lower it towards the ground like you do with a dipole. At 40 meters NVIS performance is even worse, but WOW the DX capabilities are nice even while the azimuth pattern is a four lobed cloverleaf restricting this nice low-angle gain to four general directions.

The proof of a 160 meter full wave loop antenna’s DX performance is highlighted by my friend’s achievement with his; He just finished 80 meter WAS… Phone… QRP… using, in part, this antenna. Wow.

…But I want NVIS
The practical solution is to keep your 160 meter antenna where it is and add a new simple 80 meter dipole 50 feet or less in height. This pair will team up nicely to get you want you need for 80 meter NVIS in addition to DX capabilities. Keep the 80 meter dipole well away from the 160 meter loop.

The sister web site to Ham Help Desk published several simulations of dipole discussing 40 meters and NVIS at…

Dipoles that are not too high are a quick answer for NVIS.

Other Techniques
Quadrature feeding two orthogonal dipoles, as discussed elsewhere on Ham Help Desk, yields circular and selectable polarization. This technique leverages what the ionosphere sounding folks use to probe the ionosphere at HF frequencies. This is what I am trying this year for the Virginia QSO Party. We will see how well it works.

Conclusion:
Big Full Wave Loops provide good NVIS at their native full wave frequency, but become more like DX antennas at higher frequencies. Loop antennas provide impressive performance at higher frequencies and are, thus, a great no fuss and simple antenna. However, other than the base full wave frequency, this antenna is less than ideal for NVIS above its base full wave frequency.

The above EZNEC plots detail the difference in gain you can expect with the loop antenna at different heights. For loops it seems higher is better. Other expensive improvements include laying a network of ground wires in a crisscross pattern underneath the loop. The simulations for this are not shown, but do reveal a real benefit in the total energy performance. I don’t have an unlimited supply of wire… do you? We will try to stick with the more practical antennas here at Ham Help Desk.

If 80 meters NVIS is your goal, consider a dipole or a full wave 80 meter loop rather than a 160 meter loop.

Perhaps he is right for many things, but for ham radio folks evaluating antenna choices a popular answer for the height of a vertical antenna for the HF bands appears to be 43.

Be sure to check out the many posts about the 43 foot antenna here at Ham Help Desk.

If you have been in the market for a vertical you have probably noticed the availability of a “tuner required” vertical which is forty-three feet in height above a reasonable ground plane of radials. Indeed Zero-Five, DX Engineering and others offer this exact configuration in their model lineup claiming “all band” operation from 160 to 10 meters. Can this really be true?

This is also known as a 13 meter vertical. Here is a discussion of why this compromise length exists with some pitfalls.

Forgoing the need for a tuner (which is arguably not too big a deal) let’s have a look at the predicted patterns using EZNec. To set up the simulation, I copied a vertical antenna with four radials from the Cebik model set available for purchase on his web site. The only thing I changed was the antenna height and the radial length.

• Antenna height = 43 feet AGL with the bottom about 3 inches above ground
• Four Radials of 1/4 wave each to simulate an efficient low impedance ground resulting from layout of many radials

I chose Cebik’s vertical example to ensure I leverage his knowledge of how to model radials reasonably well in EZNec which, in my case, uses NEC2 as the engine. NEC2 does not model underground radials so Cebik’s technique is a welcome insertion of NEC2 trickery. Plus, I wanted to capture all the appropriate assumptions he makes for vertical over radials EZNEC antenna simulation.

The antenna looks like this…

View of 43 foot vertical antenna in EZNEC

Now here is the predicted patterns using a typical frequency of the main HF bands. Note the “Primary” trace is the one plotted for the 10 meter band…

Patterns of 43 foot Vertical Antenna on the major HF Bands

The peak radiation angles and relative antenna gain for each bands are:

• ~ 5 dBi @ 57° for 10 meters – impressive, but high angle
• ~ 4 dbi @ 37° for 15 meters
• ~ 1 dBi @ 16° for 20 meters – nice low angle
• ~ 0 dBi @ 25° for 40 meters
• ~ -2 dBi @ 29° for 80 meters – this is quite functional
• ~ -8 dBi @ 23° for 160 meters – lossy, but it does work

Several things are apparent:

• The antenna has “better than nothing at all” performance on 160 meters and is certainly interesting for this difficult band.
• Low gain, but good low angle performance is apparent for 80 through 20 meters.
• The 15 meter band shows some actual gain, but at a high angle of about 30-40 degrees – This may or may not be what we want for our DX purposes on this band. That said, it is noteworthy to see it still has unity gain at lower angles.
• The 10 meter band, the black trace marked as Primary, shows peak energy well above 45 degrees elevation. I suspect this will be less than desirable.

You can see why the ten meter case has the high angle radiation when you look at the currents along the vertical as shown here…

View of 43 foot vertical operating at 28.3 MHz

The opposing current phases destructively interfere at some angles and constructively interfere at others.

Is this an all HF band antenna? Well, because it operates at no particular “tuned” length for any HF band, except maybe 60 meters, you will always need a tuner. So, sure, it can tune up anywhere the tuner (or matcher if you prefer) can match. If you have to have just one antenna for HF, maybe this is a good choice, especially during the current great low band conditions in this low sunspot point in time.

A better reason to consider this antenna is for reasonable 80-20 meter use and as a practical thing to try for the 160 meter band. Because you can tune almost anything to almost any band, it is possible to get 10 and 15 meter use too with the propagation issues described above.

Other advantages for this 43 foot antenna is expense. You can have one for a few hundred dollars and several major antenna manufacturers, noted above, make them. The variables between the manufacturers is likely strength in materials and other mechanical design issues. Look to Eham for evaluations.

In my quest for a do it all vertical to replace my 16.6 foot copper pipe my choices include:

1. Multiband Fixed Height Vertical using Traps
2. Multiband Variable Height Vertical using the SteppIR BigIR III
3. Multiband Fixed Height Vertical using an antenna matcher in the shack – such as this 43 foot concept
4. Multiband Fixed Height Vertical using an antenna matcher at the antenna base – 43 foot concept again
5. Forget the vertical and get a dipole

Because I am getting good results on 20 meters with my 16.6 foot vertical, I am not interested in dipole solution #5… yet. Thus, I desire to bring some closure to this vertical installation and make it the best it can be.

I am still leaning towards the SteppIR BigIR Vertical even though it is a bit expensive. Being able to tune the antenna precisely to the appropriate length is a great feature resulting is little standing waves on the coax.

However, the simplicity of solution #3 means no additional wires to the antenna to power an automatic remote tuner or drive the SteppIR motor. This is just radio (with built-in matcher), coax, antenna. I lose some power in my very long coax with the standing waves, but have a much more reliable system. Uncomplicated solutions are certainly well worth considering.

No matter what your choice, if you want a vertical, consider the investment you will need for the radial system. Get the DX Engineering Radial plate and just do it. It really helps.

One more point is worth mentioning. The various makers of 43 foot vertical antennas all suggest the use of a 1:4 balun. Some suggest using a balun model made specifically for “tuner use” with the idea these specialized units have the robustness needed to handle the less that ideal voltages and currents. A nice balun costs good coin and is certainly worth it. Just be sure to roll this expense into your trade study when comparing this 43 foot solution with something like the BigIR vertical.

Also watch out for aluminum components near the ground. Certain soil conditions will dissolve aluminum.

DX Engineering and Zero Five Antennas seem to be in hot competition in the vertical market and they both have an approximate 43 foot system to sell you. If you are in the market for this kind of vertical start your trade study with these two manufacturers.

Good luck.

For some while SteppIR has offered two vertical versions of this adjustable length antenna: one for 6-20 meters, the other 6-40 meters. Also, an optional base load coil option is available to extend band coverage to 60 and 80 meters.

The web site…

…offers an excellent view of what is inside the control boxes of the BigIR Vertical and the 80 meter coil.

You get an instant appreciation of how SteppIR Antennas, Inc. has addressed how to make an antenna element move in and out in an almost infinite number of positions using a stepper motor.

The 80 meter optional coil is also a clever way to extend the capability of this antenna to the lower bands albeit with compromised performance indicative of any “electrically short” radiator. This is, of course, due to antenna physics, not anything SteppIR Antennas, Inc. did.

The manufacturer’s web site…

…also shows a photo of the inside, but which does not immediately reveal this is a custom PCB switch using a PCB .

The 80 meter option assembly is very large and I began to wonder why.

Because the 80 meter option is a tapped inductance, as clearly shown in the photos contained in the web site referenced above, one might consider using high quality RF switches or relays to select the amount of inductance. A switch to bypass the coil entirely when using the SteppIR BigIR for 40 to 6 meter work is also sensible.

What the photos on the web site above made clear is SteppIR Antennas did not use RF relays to perform the select-coil-tap function, but manufactured their own switch using printed circuit boards arranged in a rotating contact switch operated by a stepper motor. Obviously, they are capitalizing on the great experience they have with stepper motors and the way they control it with their desktop controller.

As noted by the fine folks on the SteppIR email list, the coil taps have potentially large voltages that could easily arc over relay contacts when operating at higher powers.

My original version of this post forgot this important point. Now I understand why SteppIR went to such trouble to produce a very large switch with large separation between the “contacts” to handle the high voltages present. The cuts in the PCB material between each switch contact point reinforce this point.

The list of the issues with the 80 meter coil option include:

• Home-Brewish Inductor Tap Switch – The flimsy nature of this system still begs for a better approach, but I have to admit I cannot think a better approach in this price class
• Stiff wires on the moving switch contacts produce stress – high strand count wire may make better sense
• Weather exposed terminal connections for the stepper motor wiring – a good connector approach would be an option I would gladly pay extra for
• PCB trace-widths may not handle full power at the the 1,500 watt rating especially with the higher currents feeding the lower impedance of a short monopole. My calculations for 10 °C rise for the currents expected into, say, a 25 O antenna start at 0.1 inch with 2 oz. copper thickness. The PCB board has ample room for wider trace widths.
• Power off default potentially undefined

Soon I will post some details of suggested improvements to take SteppIR’s brilliant thinking into a better engineered approach.

A purchase of the BigIR vertical is a certainty for me. The enormous 80 meter option is a reasonable value at under $400 and would be a for-sure purchase if it wasn’t so large and I had not seen the inside home-brew switch. Still, the high voltage tolerance of SteppIR’s unique rotating PCB switch is, perhaps, a clever affordable solution that brings a good solution at a good price point… nothing wrong with that.

In SteppIR Antennas’ defense, product development can be quite a pain, especially when targeting products for notoriously stingy hams. The fact they have products for us to buy with their unique twist is a good thing for amateur radio.

To highlight their cleverness this is a best guess schematic of the RF paths…

The RF Paths in the SteppIR BigIR 80 m Option Coil

The most interesting portion of this schematic is the wiring of the coax wrapped toroid. It is another clever SteppIR design feature that helps match 50 ohm coax with the ~ 14 ohm impedance of a series inductance base loaded monopole antenna.

You are doing a good job SteppIR Antennas. With a few tweaks you will have a near perfect product. On the other hand, for the price you just might already have a near perfect product.

SteppIR, please take note… I would be delighted to pay another $100 for a good weather proof connector for the motor signals.