Both antenna types approach the vertical HF antenna problem with unique solutions.

The 43 foot antenna never changes height. Its height is such it never places the high impedance part of the antenna at the feed point at any desired operating band to give a tuner a chance to turn this wild impedance to 50 ohm resistive.

The BigIR literally adjusts height to make itself just the right length to resonate and bring the feed point close to 50 ohm resistive.

These are two interesting and opposite solutions.

Let’s look at the plots for 10, 15, 20, 40 and 80 meters again…

BigIR vs 43 Foot at 10 meters

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BigIR vs 43 Foot at 15 meters

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BigIR vs 43 Foot at 20 meters

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BigIR vs 43 Foot at 40 meters

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BigIR vs 43 Foot at 80 meters

BigIR points include:

• Beats the 43 foot handily at 10 meters
• The 1/4 and 3/4 modes for 10 and 15 meters offers a great choice in antenna pattern
• No antenna matcher required since the antenna length does the tuning for you
• Antenna SWR under 2:1 a completely reasonable expectation
• SteppIR’s clever variable length antenna and optional 80 meter coil have moving parts resulting in complexity
• BigIR needs 4 (or 8 with 80 meter coil) control wires to operate antenna from shack
• For what you get, the antenna cost is a great value, but is, indeed, not cheap

43 Foot Antenna points include:

• Provides a significant benefit for 20 meter DX with good gain and potentially low take off angle
• Requires some kind of antenna matcher for every band except, perhaps, 60 meters, at antenna feed point or in the shack
• Balun helpful to ensure currents are fully driven to antenna if not using matcher at the antenna base
• Arguably much simpler antenna system with no moving parts
• If matcher located at antenna base, additional wiring required

…and…

• Neither antenna differs much at 40 and 80 meters
• The 43 Foot antenna may provide some use at 160 meters – better than nothing I guess
• The 43 Foot antenna system between 1/3 to 1/2 the cost of the BigIR system not including the required antenna matcher for the 43 foot system

Which one to pick? Well, for me the answer is not obvious. I like antennas that present low SWRs to the feedline. I like simple antenna systems. I also like 20 meters a lot. I have no problem with the cost of the BigIR.

One obvious answer is to get one of each and switch between the two. Well, I do have the room and do have the switch. However, the whole point of the Shootout is to decide the most effective antenna if you could only have one.

With the upcoming sunspots the 10 and 15 meter bands look very attractive and a good ground mounted vertical may be just the thing. However, I have got to wonder if a modestly high 10 meter dipole won’t work better than the ground mount.

I am inclined to take advantage of the DX Engineering Zero Five price war and just get the 43 Foot antenna for now since it is a plug and play system to replace my current 16 foot vertical (which works great on 20).

My preparations focus mostly on the Virginia QSO Party where NVIS 40 and 80 meter antennas along with a decent 20 meter DX antenna are a great combination.

Whatever choice you make it is nice to know great products like the BigIR and the 43 Foot offerings are available. Just remember to not cheat yourself concerning a good ground system; Both antenna systems are incomplete without it. You need lots of radials. Read the ARRL Antenna book to nail down the reasons why.

A good vertical antenna is a sensible first antenna and a great addition to your dipole. Either choice will offer the possibility of lower takeoff angle to improve your chances at DX contacts. These two choices deserve a good hard look for your first or next vertical.

The 43 foot antenna uses an antenna matcher (tuner) somewhere in the transmission line to offset the non-resonant impedance; This is the case for all bands except, possibly, the 60 meter band where 43 feet is close to a quarter wave.

The BigIR max height is about 32 feet or about an 1/8 wave antenna. The BigIR continues to not need an antenna matcher by adding an inductance in series with the 32 foot radiator. This inductance brings the antenna system into resonance with a resulting impedance of about 13 ohms. A 4:1 balun wound on an internal toroid transforms this to about 50 ohms… a slick system.

Here are the two antennas with radials appropriate to 80 meters…

The 43 foot and BigIR antennas in EZNEC

…and the plots…

43 Foot and BigIR Compared at 80 meters

Very very close…

Points include:

• Both antenna exhibit 0 dBi gain peaking around 25 degrees
• Like with 40 meters, the 43 foot antenna puts just a little more higher current conductor higher in the air, but just a little
• The SWR for the BigIR calculates fine for this, but I have found EZNEC a bit difficult to predict SWR with real-world lengths. The folks at SteppIR suggests the SWR will be under 2:1 for the 80 and 75 meter bands when using their 80m option coil
• I could not simulate any respectable SWR with EZNEC for anything between 3.5 and 4.0 MHz – I suspect your results may be better since folks seem to have reasonable results

I would call these results a wash. Both antennas work on 80 even though both are short for this band. It might seem surprising they are so similar despite the height difference. However, this pattern similarity reveals not all of an antenna’s length is actually used for radiating effectively. Indeed, the high current portion of the antenna does much of the work and in this case the lower portion of the antenna is this higher current area.

Here are the two antennas with the current magnitudes at 7.15 MHz.

The two antennas energized with 7.15 MHz.

Once again, the 1/4 wave antenna’s currents are nil at the top and maximum at the bottom. Assuming you have a good radial system on the ground with low ground resistance this should be near the ideal of 36 ohms impedance. This results in a SWR of about 1.4 or so. The fact the BigIR’s 32 foot height won’t simulate a low SWR is probably the result of simulation artifacts. Either way this is good demonstration where the ideal SWR of 1:1, where the feed point impedance is 50 ohms and a good match for the coax, is not the ideal since this means you have 36 ohms antenna reactance (turns your RF into signal) + 14 ohms ground resistance (turns your RF into heat). That’s another story though.

Here is the plot…

43 Foot vs. BigIR Vertical at 7 MHz

Hmmm, not that different… not that different at all. Points include:

• Both antennas show their best lobe of energy at about 27 degrees elevation at -0.5 dBi gain
• The 43 foot has just a little more higher current radiating portions of the antenna a little higher than the BigIR
• The SWR (at least for the 36 simulation model) is nice and low
• The SWR for the 43 foot is about 5:1 for 50 ohm feed and a respectable 3:1 using the 4:1 transformer

Neither is a clear winner. The good news is neither is a clear loser. They both do the job of getting radiating metal up in the air to make contacts.

The 43 foot antenna provides the potential for better efficiency since its impedance is much higher than the ground losses induced by the radial system. This suggests you might be able to get away with a worse radial system with less efficiency penalty… I still would put a lot of radials in since it is so easy to do.

Onward to 80 meters next…

As always, each EZNEC simulation is based on a model from the excellent collection of NEC files available from the late Cebik.

Here are the two antennas with the current magnitudes at 14.1 MHz.

The two antennas energized with 14.1 MHz

As usual, the 1/4 wave antenna’s currents are nil at the top and maximum at the bottom. Assuming you have a good radial system on the ground with low ground resistance this should be near the ideal of 36 ohms impedance. This results in a SWR of about 1.4 or so. This is good demonstration where the ideal SWR of 1:1, where the feed point impedance is 50 ohms and a good match for the coax, is not the ideal since this means you have 36 ohms antenna reactance (turns your RF into signal) + 14 ohms ground resistance (turns your RF into heat). That’s another story though.

Here is the plot…

43 Foot vs. BigIR Vertical at 14 MHz

Well well, the 43 foot has some clear benefit here. It potentially has a lower take off angle and a bit more gain than the 1/4 wave. It is not staggeringly better, but if you are trying to get every dB you can, the 43 foot wins. Points include:

• The 43 foot vertical has its peak lobe at a nice low angle of 16 degrees with a gain of about 1.3 dBi
• The 43 foot has a full half-wave radiating section well above the radiating portion of the 1/4 wave which may help your signal clear local obstacles
• The 1/4 wave BigIR has its peak lobe at 27 degrees with -0.3 dBi.
• The SWR for the BigIR is around 1.5… perfect
• The SWR for the 43 foot was far more than 10:1 with a 50 ohm coax feed. If you have a 1:4 balun the SWR gets tamed down to around 7:1. Obviously a matcher is needed and contributes its own losses

Who wins? Well I don’t know. Analysis is showing clear benefits, but nothing that would move the S-Meter more than a couple of S-Units.

The fact the BigIR is tuned by adjusting its height makes it possible to reach the theoretical 36 ohms. This puts significant requirements on your radial system if you are to have good antenna efficiency.

The very fact the 43 foot antenna is being fed at a higher impedance point suggests the radial system’s impedance need not be as low to maintain good efficiency. Then, however, there is the need for the tuner somewhere with potential added losses.

I am using the equivalent of the BigIR with my 16.6 foot copper pipe monopole antenna in my backyard over 28 radials each 33 feet in length. It works on 20 meters, but I am not busting pileups with 100 watts. Would the 43 foot approach give me an edge with everything else being the same?

Stay tuned for more band analysis.

All three antennas, the 43 foot and the BigIR in 3/4 and 1/4 wave mode and their antenna currents are shown below.

All three antennas running at 21 MHz

The current profiles for the 3/4 and 1/4 mode are just like any other antenna the same electrical length. The 43 foot antenna constrains the electrical length to around 7/8 wavelength.

Here are the three patterns superimposed…

Elevation Gain Plots of 43' and SteppIR BigIR 21.2 MHz

Here we see:

• The 43 foot vertical has its peak lobe at 37 degrees with gain of 4 dBi
• The 3/4 wavelength mode of the BigIR has its peak lobe at 47 degrees with a gain of 3.8 dBi
• The 1/4 wavelength mode of the BigIR has its peak lobe at 27 degrees at 0 dBi gain
• The SWR for the BigIR is nice and low for both the 1/4 and 3/4 mode. It was slightly better in the 3/4 mode.
• The SWR for the 43 foot was off the charts

The 43 foot vertical definitely requires a tuner. Both DX Engineering and Zero Five suggest if you are going to use the tuner in your shack then place a 4:1 transformer at the antenna feed. This converts the 50 ohm coax impedance to 200 ohms. Indeed, when EZNEC is used to check SWR at 200 ohms, it is far lower, but still about 5:1.

At 15 degrees or so elevation all three antennas show similar energy with the BigIR showing an edge in both the 1/4 and 3/4 wave modes. At higher elevations the 43 foot begins to show an advantage.

It is hard to declare a winner with this data. We will need to analyze more bands. Stay tuned to the RSS feed.

All three antennas are shown below with the relative currents displayed.

All three antennas at 10 meters

Since 28 MHz is so short, the current profile along 43 feet of vertical radiator is long. The SteppIR BigIR in 3/4 wavelength mode shows a full half wave of current high up along with the 1/4 wave at the bottom. This is, of course, the definition of 3/4 wave. Finally the simple 1/4 wave vertical mode is on the right.

Here are the three patterns superimposed…

Elevation Gain Plots of 43' and SteppIR BigIR

The following characteristics are revealed:

• The 43 foot vertical has its peak lobe at 56 degrees with gain of 5.6 dBi
• The 3/4 wavelength mode of the BigIR has its peak lobe at 47 degrees with a gain of 3.9 dBi
• The 1/4 wavelength mode of the BigIR has its peak lobe at 27 degrees with a gain of 0 dBi
• Suprisingly, the SWR calculated from 28 to 29 MHz was well under 2 and often under 1.5 for each antenna

This comparison reveals each can work at 10 meters, but one has to argue the 43 foot antenna’s angle of radiation is a bit too high for practical use.

The 3/4 wave mode of the BigIR edges out the 1/4 wave mode just slightly at the low angles we desire for long haul DX. Still, who knows, you might gain some benefit from the 3/4 mode if your soil conditions and location are different and the BigIR lets you choose either. Another way to look at the 3/4 mode is a large half-wave radiator is somewhat elevated which may help clear obstacles close by; That could be a serious benefit over 1/4 wave. Pretty nice.

Next time we will analyze the 12 meters band the same way as above and keep going until we hit 160… or maybe just 80.

Stay tuned to your RSS feed.

Trap verticals have been around for decades and many use them with success. However, two new designs have achieved some notice and are attempting to eat into the trap vertical market: The 43 Foot Tuner Required Fixed Length antenna and the Variable Length SteppIR BigIR antenna.

During this shootout we will compare a 43 foot antenna with the BigIR one band at a time. The base model for this analysis will use a ground vertical model from Larry Cebik’s NEC model collection which simulates the benefit of a good radial system. The radial lengths will be adjusted for each band and will be identical for both the 43 foot and the BigIR. The 43 foot vertical will, of course, never change height. The BigIR will be “adjusted” in height for minimum SWR at the test frequency. Where the BigIR can be 3/4 wavelengths height that will be calculated too.

HF Band Analysis:

Band	Antennas		Notes
	43 Foot	BigIR
160 m	1/12 wave	n/a	The Top Band is great, but both antennas are woefully short
80 m	1/6 wave	1/8 wave	Having an 80 meter vertical is worth while
60 m	1/4 wave	1/6 wave	Its nice to have a way to use this new band
40 m	1/3 wave	1/4 wave
30 m	4/9 wave	1/4 wave	WARC bands are often the forgotten bands
20 m	5/8 wave	1/4 wave	This is an important DX band
17 m	4/5 wave	1/4 wave	Another good WARC band
15 m	7/8 wave	1/4 and 3/4 wave	We will compare three antennas since the BigIR can tune 15 m two ways
12 m	17/16 wave	1/4 and 3/4 wave	Ready for sun spots
10 m	5/4 wave	1/4 and 3/4 wave	Ready for sun spots
6 m	9/4	1/4 and 3/4 wave	Just for fun

Note, all the above comparisons have the antennas ground mounted, not elevated.

The big 43 foot next to the BigIR set to 10 meters 1/4 wave

We will analyze each band in turn in upcoming posts and link to them from here so bookmark this page now and stay tuned…

We do too.

Thanks Mel. The use of a wall stud finder is an excellent tip.

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.