SteppIR 3-element yagi

Written by admin On May - 15 - 2009 0 Comment

Notes about the SteppIR 3-element

See how I’ve added a 40M wire element to the SteppIR dipole

The 3-element 40-6M SteppIR on the U.S. Towers MA40 (with MAF raising fixture and MARB rotating base) about 5 minutes after the installation was complete on May 2, 2009.While I was at it, I replaced the aging RG-8 coax with a good-quality RG213, and removed about 10 feet of unused mast above the antenna (eliminating at least 20 lbs of top-end weight and a square-foot of windload).

Larger view

After a couple of years of frustration with the Mosley Classic-33 (PDF) trapped triband beam, on March 31, 2009, I calledFluidmotion and ordered a SteppIR antenna.

The antenna arrived ahead of schedule on April 24. I spent a week building and double-checking things, and it was in the air at 1810z on May 2, 2009.

First contact was with T70A (San Marino) on 20M phone, during the ARI DX contest at 2043z on May 2.

The old antenna

The CL-33 was a great antenna for a new contester. I honed my skills on it since first putting it up in September 2004, making many tens of thousands of contacts mostly in CW and RTTY contests. The CL-33 is good for CW orPhone bands, but not both. As I am now interested in more than a few SSB contests each year, I need something that can be used across the CW and phone bands. I have the CL-33 set for CW, and would never have a phone-band-only antenna.

Also, the CL-33 is a trapped tribander. The design of 3 elements on an 18-foot boom produces very good gain, but the traps reduce that gain. Some say each set of traps in an antenna system can reduce gain by as much as 1 dB.

“G6XN calculates that the loss for an input of 100 watts in the driven element traps is 25 watts and that in the parasitic elements to be 18 Watts, a total loss of 3.06 dB for a three ele tribander.”


Hmmm. Let’s say the tribander has 8 dB gain — minus 3 dB for the traps. That leaves 5 dB for me.

The SteppIR has none of these losses, takes full legal power, tunes to (or close to) 1:1 SWR everywhere, and provides max gain wherever you operate — not just in one sweet-spot on each band (something no antenna with fixed-length elements can do). With the Classic-33 set for the CW portion of 20M, I can’t operate in the Phone band where the SWR soars far above 3:1 — running high power for long into that mismatch would soon burn up the coax feedline.

Here are the specs of the two antennas:

SteppIR 3-el.

The Mosley specs are cited in dBd (gain over a dipole) while the SteppIR specs are dBi (gain over isotropic radiator).

The Steppir dBd column represents the dBi figure minus 2.15 dB.

The 6M figures for the SteppIR assume the 6M passive element is installed.

While the Mosley Classic-33 specs show front-to-back rejection, the SteppIR specs show front-to-rear.

Enter the SteppIR

Those who have used the SteppIR 3-element antenna swear by it. At the BCDX Club meeting on Vancouver Island, in September 2008, I had a long chat with Ralph, VE7XF, who recommended the 3-element as solid contesting gear. Ralph consistently beats me in contests, so I figure he must be right.

I ordered the 3-element plus 40M/30M dipole. This will give me good performance across all bands from 40M to 6M.

Aside from the inherent benefits of low SWR, max gain where you want it (everywhere), and high efficiency, the most important operational feature to me is the ability to almost instantly (within a couple of seconds) reverse the direction of the antenna.

From B.C., there are many times in a contest weekend when it is useful to be able to work two directions at once (bidirectional mode), or move forward and back 180-degrees. Instances include mornings when Europe and W6 are calling at the same time, or Japan and the Caribbean. Just being able to quickly “flip” to KH6 or UA0 for the mult while running South American stations means more points in the log.

The SDA-100 controller

SteppIR says my order should ship in about four weeks (estimate: end of April). However, I also ordered the upgraded controller — the SDA-100 — which could add another week or two, as the Dream Beam 36 orders come with this controller as standard equipment and Fluidmotion is still filling a few final backorders on the DB36.

The SDA-100 controller provides a few new features, including a user-adjustable auto-tracking interval (so the antenna retunes every 50 khz, or 150 khz, etc.), a USB port for downloadable firmware updates (the old controller required a chip replacement), and better static immunity, which apparently was a weak point with the old controller. For the extra $100 upgrade fee, I figured it was a good investment in having the latest model.

The manual indicates that a tuning relay (preventing an amp from kicking in while the antenna is retuning) is an available option, though details aren’t yet available.

The package of equipment I ordered includes:

  • SteppIR 3-element yagi
  • 30M/40M dipole trombone element
  • Passive 6M element
  • SDA-100 controller
  • Transceiver interface
  • 12-conductor control cable (100′)
  • Y-cable for rig and computer control
  • Transceiver cable (S18 for FT-2000)

Making the decision:
Dream Beam DB18, or 3-el. plus 30M/40M?

Choosing the SteppIR 3-element was not a difficult decision. User reports are almost all very positive — perhaps even glowing with enthusiasm. My most difficult decision was whether or not to wait for the pending Dream Beam DB18, which has two elements on 40M, on an 18-foot boom.

At about CDN$1,200 more than the 3-element + 30M/40M dipole, the DB18’s additional features are an extra 30M/40M element (it’s just CDN$500 to get one as an add-on to a basic SteppIR model), a slightly longer boom to accommodate the additional trombone element, and the special relay switching to make it all work.

The 2-element, 16′-boom yagi on 30M and 40M delivers significantly more performance than a dipole, but has about 10 sq. ft. of windload — which is above the max load my small U.S. Tower will carry. I could have lived with that (the tower is usually cranked down anyway), but then there was the undefined wait-time for the DB18.

SteppIR is only taking wait-list requests right now (April 2009), as the DB18 is not yet in production. Some reports say orders will start in mid-May at the Dayton Hamvention — with delivery a few months after that. Here in B.C.’s Interior, if I don’t have the antenna in the air by late October, I would have to wait until April to raise it. That would be a long, hard winter with a box in the garage.

Rather than wait perhaps as long as a year, and pay $1,200 more for an antenna that would be the same as a 3-element on 20M through 10M, I decided to just go with the 3-element plus single 40/30 dipole.

I’d love to have the higher gain on 40M and 30M, but with a max. height here of 45′ (that’s 42′ + 3′ of sturdy mast height), that gain wouldn’t do justice to a 2-element yagi (gain at typical take-off angles to Europe, for example, would be modest), yet the heavier, higher-load antenna would put much more stress on the tower. So, I will use the SteppIR 30/40 dipole at 45′ to work what I can at that low height, and if necessary continue to work on my 40M vertical arrays for long-haul DX on that band.

After all, I can buy a LOT of coax and relays for phasing my wire verticals with the $1,200 I’m saving, hi.

See how I’ve added a 40M wire element to the SteppIR dipole

Not so bad even low

Fortunately for me, even a 40M dipole at 45′ will perform quite well at this QTH. See Terrain Analysis page for more details.

Here are some representative charts showing the performance of the SteppIR 40M dipole at various heights at this QTH, which has about 300′ of elevation drop-off to Europe and much of North America.

The chart above shows the SteppIR 40M dipole performance aiming at Europe from this QTH — at antenna heights of 30′ (tower cranked down), at 45′ (tower up), and the reference at 70′ (1/2-wavelength) over flat countryside.

The dipole at 45′ will average about 2.1 dBi to Europe over all the expected angles of arrival, with a useful peak of about 5 dBi at 5 degrees elevation.

At all arrival angles of 6 degrees and lower, it will perform better than at 70′ over flat terrain.

The 30′-high dipole will average -0.4 dBi over most angles, with a max gain of about 3 dBi at some low and useful angles.

The 70′-high dipole to Europe over flat terrain would have an average gain of about 0.8 dBi.

The chart above shows the SteppIR 40M dipole performance aiming at the U.S. from this QTH — at antenna heights of 30′ (tower cranked down), at45′ (tower up), and the reference at 70′ (1/2-wavelength) over flat countryside.

The dipole at 45′ will perform as well as or better than a dipole at 70′ over flat terrain at most takeoff angles, with a few exceptions at some specific angles (where the red line dips lower than the green line).

To the U.S., the dipole at 45′ will average about 5 dBi over all the angles of arrival over time — the same 5 dBi average as a dipole at 70′ over flat terrain. At 30′ it will average about 3.5 dBi.

Shipping Diary

March 31, 2009 Faxed order to Fluid Motion
April 17, 2009 Received notice by e-mail that my order was ready to ship via UPS. Credit card charged.
April 21, 2009 Received UPS e-mail notices that three packages were on the way, for delivery on April 23. This was a wonderful surprise from Fluid Motion, as the estimate at order time was three to four weeks, plus perhaps a week for the upgraded SDA-100 controller.
April 22, 2009 Called UPS 1-800 to request that the packages be held at the local Customer Center rather than delivered to my home on April 23 (nobody home to pay the Canadian tax and UPS brokerage fees).I was told they can’t do that. The first delivery attempt has to be made to the ship-to address, but after that I can request a hold.
April 23, 2009 Today was the scheduled delivery date. I arrived home from work to find a yellow UPS note on the front door. They were here, but with a COD package, they needed payment and a signature. No kidding, Sherlock.I visited the UPS Customer Center in town, only to be informed my packages were actually being delivered by Purolator (who does UPS’s residential deliveries in our community).
April 24, 2009 Left work at 3:45 p.m. and drove to the Purolator shipping warehouse, which is about half a mile from where I work. They don’t have a customer desk, but I went into the adminstrative office and explained that I was expecting a delivery that would need COD fees paid.They checked the computer and said the packages were on a truck for delivery, but if I waited a few minutes, the driver would be back for the day. I paid the fees — $460 in taxes and UPS brokerage charges — and went to my car to wait.As I dialed my cell phone to call my wife, I happened to glance at the open door of the loading dock. There was a big box with the SteppIR logo on it. A big box, and another smaller one next to it. And a little one — that would be package number three.I grinned about as wide as Texas, and asked my wife to bring the van as my car couldn’t carry the largest of the boxes.Got it all home by 4:30 p.m. — just three weeks from the day I placed my order with Fluid Motion.If I had not intervened by going to the shipping center, I would have waited until Monday to receive my SteppIR — and only by being at home all day and ditching work, which I would never do because I like my job (hi boss).

I say this every time I get hosed by UPS, but I will never choose to use UPS again unless there are no other options. They simply lack logistic convenience for residential recipients. Alas, there rarely are options.

Unless you are retired or can otherwise be at home all day on the expected delivery date, don’t use UPS to ship an item across the border from the U.S. to Canada (i.e. that you’ll have to sign for or pay fees upon delivery). If you don’t stay home on delivery day, expect to pick up your package at least one day after that, or a whole weekend if the first attempt was on Friday. And goodness knows what company will actually attempt to deliver the package to your door — you’ll have to play Inspector Morse before you ever track down your shipment. [rant off]

Antennas, Uncategorized

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