Variable frequency antennas from SteppIR

The SteppIR concept is very simple. Antenna elements housings are made from fibreglass. A copper strip runs inside the element housings, and the length is changed by reliable stepper motors. In this way element lengths can be varied by the operator. This means the operator can design an antenna which is maximised for front-to-back ratio, gain, SWR or a combination of any of these parameters. Conventional yagis with alloy tubing elements are always designed at a centre frequency, with performance falling away the more one moves from that frequency. With the SteppIR, the elements lengths can be changed to be ideal for any selected frequency.

Additional features are instant beam reversal, and "bothway" mode (for the 3 and 4 ele yagis) where the antenna fires in both directions at once. Optional transceiver interfaces are available for Yaesu, Kenwood,  TenTec and ICOM radios so that antenna length changes automatically with changes of frequency / band. The transceiver interface consists of an optional PC board inside the controller and a lead specific to your transceiver.

I have had the 3 element antenna in the air at my GW3YDX station, driven by various transceivers during the past ten years, and it does all it says. People are particularly amazed at the effectiveness of the 180 degree fast beam reversal feature. I thought it was a gimmick before I used it, but it has helped cracking a pile-up when the rest of the pack are still turning their antennas. VSWR's are not only low on all bands, but anywhere within those bands, as the antenna adjusts itself following the frequency on the radio (for instance the length changes every 50 KHz on 20 metres). The quality of all parts is extremely good, and the antenna went together with no problems at all.  

 

 
DB11 - Efficient mini-beam

Click here for more info

2el yagi

Click here for more info

3 el yagi - 20-6m

Click here for more info

3 el yagi 40-6m

Click here for more info

4 el yagi 20-6m

Click here for more info

4 el yagi 40-6m

Click here for more info

 

SteppIR verticals

Click here for more info

DB18 40-6m  2el on 40/30

Click here for more info

DB18E 40-6m

Click here for more info

DB36 - 4el 40-6m

Click here for more info

DB42 - 5 el 20-6, 3 el 40/30

Click here for more info

New SDA 100 controller - standard with all antennas

 

 

For an  excellent video of a 2 el + 40/30 at PH0AS, visit

 http://www.youtube.com/watch?v=hvAxgAQeQMo&feature=channel_page

 

Comments from our customers

I just smashed the pileup of JAs who were calling 3D2WW on 20M. Got through on the 3rd call with the L-4B on low power, so no great QRO. I have *never* had that sort of performance before. (G3XAQ)

I don't think anyone can beat the service from Vine Antennas in the UK. I ordered my 3L Steppir from Ron, GW3YDX, a couple of weeks ago by telephone and within 24 hours I was starting to assemble it. (The
order was placed about 2.30pm and the antenna arrived about 10.30am the following morning.) I live about 200 miles away from Vine Antennas.

The antenna went together without any problems and I put it up at 55 feet on my tower just in time for the bad gales that swept across the UK last week. Needless to say the Steppir came through the 70/80mph winds unscathed.

Although it is very difficult to compare it with the two element quad that I had up previously (that came down in the previous gales), I have the feeling it is working better. The 180 degree and bi-directional options are marvellous. Well done and thank you to Steppir and Vine Antennas.

73 de Chris, G4BUE

I live on a very stormy location, The Faroe Islands, and have four guys from the same point on my Big Steppir, and it have survived wind speed up to 120 mile. pr. hour.
Im using guys that is a little thinner than flag lines, and that is ok. Started out with fish lines, but they stretch in the wind and get too long, and that can be a problem in a heavy storm, the antenna get unstable.
The Steppir vertical is the strongest antenna I have had, super quality.

Otto/OY9R

I would just like to say, (something owners already will know) how very impressed I am with this antenna, the F/B is tremendous and the design and construction is very good too. It took me longer than most to construct it due to a disability, (Spinal injury) but the wait was absolutely worth it. I found all the parts light enough to be able to manage without too much help, trying to be independent with my condition is difficult but I struggle on. Anyway, I would like to say it all worked out fine and great thanks to everyone on this list with encouragement and help with my decision in making my mind up over my old TH5mk2 to my new Steppir 3 ele w 30/40m. I now have my ultimate station Collins S-line and Steppir.  Also thanks to Ron of Vine antennas who has been marvellous and who supplied me with the antenna. 

73 Max M0GHQ

Tnx for the good work.. Very fine antenna, been testing and very pleased with it.  Never had a Front to Back like this. very impressed

Marco PE2MC

(4 el) Thank you for this great service and all the information you gave me. I shall sure tell people what a great service you gave me, and will sure buy more things from you if I need them

Didier ON8VK

Many thanks for your hospitality on my visit, I have finally got the 3el Steppir up at 13m AGL on the end of 34m of LDF 4-50, after some problems with my mast seals. I have also fitted the 6m and 4 m passive elements, it tunes perfectly on all bands and performs brilliantly. Originally I had a 5 el Tennadyne LP on HF, 4el 6m and 5 el 4m beams. I measured several UK beacons and they are all stronger on the new system by 3- 6 dB on 6m and 4m, presumably the closely nested separate vhf beams were interacting too much. On HF I have worked everything heard in one or 2 calls- so can't complain. The 180 deg reversal is great for time saving as there is little need to turn the beam round more than in a 180 degree segment.

Best regards - Andy G4EZT

SteppIR working Great!!!!!!...a wonderful antenna.....much better than the old A3S....plus all the WARC bands...(EI6JN)

Tremendous. Really amazing performance (G3MLO)

I thought the antenna would be good, but not THIS good (G0FWX)

No pile-up takes more than one or two calls with this antenna (GM4NFC)

This antenna is incredible (F4EZE)

More than great (7Z1UG)

The antenna is the best on the market (LA4UOA)



 

Our remarks on using a SteppIR 3el yagi here at GW3YDX for the past ten years.

How would you like to

Now you can do all these with a SteppIR dipole or yagi antenna

We can also tell you that everyone has been totally amazed and delighted with the performance of this antenna, and it has been EXTREMELY RELIABLE. Concerns have been expressed about the ability of the motors to operate in low temperatures. Click here for some user comments about that.

The SteppIR concept is very simple. Antenna elements housings are made from fibreglass. A copper strip runs inside the element housings, and the length is changed by reliable stepper motors. In this way element lengths can be varied by the operator. This means the operator can design an antenna which is maximised for front-to-back ratio, gain, SWR or a combination of any of these parameters. Conventional yagis with alloy tubing elements are always designed at a centre frequency, with performance falling away the more one moves from that frequency. With the SteppIR, the elements lengths can be changed to be ideal for any selected frequency.

Additional features are instant beam reversal, and "bothway" mode (for the 3 and 4 ele yagis) where the antenna fires in both directions at once. Optional transceiver interfaces are available for Yaesu, Kenwood,  TenTec and ICOM radios so that antenna length changes automatically with changes of frequency / band. The transceiver interface consists of an optional PC board inside the controller and a lead specific to your transceiver.

I have now the 3 element antenna in the air at my GW3YDX station, driven by my FT1000MP, and it does all it says. People are particularly amazed at the effectiveness of the 180 degree fast beam reversal feature. I thought it was a gimmick before I used it, but it has helped cracking a pile-up when the rest of the pack are still turning their antennas. VSWR's are not only low on all bands, but anywhere within those bands, as the antenna adjusts itself following the frequency on the radio (for instance the length changes every 50 KHz on 20 metres). The quality of all parts is extremely good, and the antenna went together with no problems at all.  

For VERTICALS - Click here

Add-ons and options

Transceiver interface (please specify type of radio)-  Click here for a list of supported radios 

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Shielded control cable is needed for these antennas. Please contact us for details.. Note - A 24V Power supply  is normally included with each antenna, and will drive the motors over control cable lengths up to 175ft (50m). For longer cables a higher-voltage PSU is required .

6m passive element kit. converts3 el / DB18 and DB18E to 4el on six, for 4 el yagi  and DB36/42 (converts to 6el on six)

 Balun for dipole (balun is already included with all yagis)

Element expansion kit  for 20-6m antennas - Dipole and 2 ele - adds one element ( includes controller update, motor, elements and boom section,  but does not include new control cable)

Element expansion kit  for 20-6m antennas - 3 ele to 4 ele( includes controller update, motor, elements and boom section,  but does not include new control cable)

40/30 converter. - Adds a rotary dipole on 40/30m to the HF yagis

Optional N-connector on driven element

PLEASE CALL US FOR PRICES

 

Like to see a video of a SteppIR being installed? Please click below if you do

http://www.youtube.com/watch?v=Vw6C9wiXcSM

Suitable rotators

Normal rules about rotator wind-loads do not apply to SteppIR antennas, as the element tubes are much more flexible than aluminium elements, and this causes some "whip" effect which means upgrading rotator loadings from those based just on surface area.

2 el SteppIR - Normal wind areas - PST641, Very windy areas - PST2051

2 el SteppIR with 40/30 - PST2051, 3el SteppIR - PST2051

3 ele SteppIR with 40/30 - normal wind areas - PST2051, very windy areas - PST61

4 ele SteppIR, and 4 el SteppIR with 40/30 - PST61

Monstir - PST71

Check our rotator page for prices and more information.

For more details, please read on........The following comments were made before the MonstIR was announced.


Currently, most multi-band antennas use traps, log cells or interlaced elements as a means to cover several frequency bands. All of these methods have one thing in common–they significantly compromise performance. The SteppIR™ antenna system is the answer to the problem. Resonant antennas must be made a specific length to operate optimally on a given frequency.

So, instead of trying to “trick” the antenna into thinking it is a different length, or simply adding more elements that may destructively interact, why not just change the antenna length?

Optimal performance is then possible on all frequencies with a lightweight, compact antenna. Also, since the SteppIR can control the element lengths, a long boom is not needed to achieve near optimum gain and front to back ratios on 20 - 10 meters.

Each antenna element consists of two spools of copper strip conductor mounted in the antenna housing. The copper strips are perforated to allow a stepper motor to drive them simultaneously with a sprocket.

Stepper motors are well known for their ability to index very accurately, thus giving very precise control of the antenna length. In addition, the motors are brushless and provide extremely long service life.

The copper strip is driven out into hollow, lightweight fiberglass support elements, forming an element of any desired length up to 36’ long. The fiberglass poles are telescoping, lightweight and very durable. When fully collapsed, each element measures 53” in length.

The ability to completely retract the copper antenna elements, coupled with the collapsible fiberglass poles makes the entire system extremely portable. The antenna is easy to assemble, and can be installed on the ground or up on the antenna tower using our Boomslide™ assembly system.

The antenna is connected to a microprocessor-based controller (via 22 gauge conductor cable) that offers numerous functions including dedicated buttons for each ham band, continuous frequency selection from 20m to 6m, 17 ham and 6 non-ham band memories, 180° direction reversal or bi-directional mode in just 2 seconds (yagi).

Frequently asked questions about the SteppIR antennas

Doesn’t having the element spacing fixed significantly compromise the antenna?

First of all, there really is no "ideal" boom length for a yagi. To get maximum gain the boom of a 3 element beam should be right around .4 wavelengths long. This would allow a free space gain of 9.7 dBi, however the front to back ratio is compromised to around 20 dB. If the boom is made shorter, say .25 wavelengths, the front to back can be as high as 35 dB, but now the maximum gain is about 8.6 dBi. Shorter booms also limit the bandwidth, which is why right around .3 wavelengths is considered the best compromise for gain, front to back and bandwidth. It turns out that being able to tune the elements far outweighs being able to choose boom length.16 feet  95m) was chosen for the boom length, which equates to .23 wavelength on 20 meters and .46 wavelength on 10 meters, because very good yagi’s can be made in that range of boom length if you can adjust the element lengths. When bandwidth is of no concern to you (as it is with this antenna), you can construct a yagi that is the very best compromise on that band and then track that performance over the entire band. It is this ability to move the performance peak that makes the SteppIR actually outperform a monobander over an entire band – even when the boom length isn’t what is classically considered "ideal". Bear in mind that a yagi rarely has maximum gain and maximum front to back at the same time, so it is always a compromise between gain and front to back. With an adjustable antenna you can choose which parameter is important to you in a given situation. For example, you might want to have a pile-up buster saved in memory, that gets you that extra .5 – 1.0 dB of gain at the expense of front to back and SWR – when you are going after that rare DX!

How is RF power transferred with the SteppIR antenna?

The RF power is transferred by brushes that have 4 contact points on each element that results in a very low impedance connection that is kept clean by the inherent wiping action. The brush contact is .08 in thick and should last thousands of cycles. The power rating of 1500 watts is continuous on CW or SSB, but as far as "key down" duty we have only tested it to 5 min. The copper beryllium tape is .545 inches wide and presents a very low RF impedance that results in conductor losses of -.17 dB with a yagi tuned to have a radiation resistance of 15 ohms, which is about as low as most practical Yagis run. The type of balun we are using can handle tremendous amounts of power for their size because the is almost no flux in the core and they are 99% efficient. That coupled with the fact that the antenna is always at a very low VSWR means the balun will handle much more than the 1500 watt rating, how much more we don't know. Jerry Sevicks book "Transmission Transformers" (available from ARRL) has a chapter (Chap 11) that discusses the power handling ability of ferrite core transformers.

What is the 180° mode and bi-directional mode?

The 180° mode allows you to "rotate" the antenna 180 degrees in about 3 seconds - Simply push a button and the reflector and director switch with each other, so you only have to rotate the antenna with the rotator 180 degrees to cover the world.

The bi-directional mode allows you to operate the antenna with gain in opposite directions, simultaneously!

What kind of gain and front to back ratios can I expect from my 3 element SteppIR yagi?

The manufacturers did extensive testing at their Moses Lake, WA range, and the SteppIR yagi performed as theory predicted. According to EZ-NEC's and YO -PRO's antenna analysis, the practical antenna gains possible with a boom 16' long, range from 8.2 dBi to 9.0 dBi. The antenna is very close to those figures from what was measured on the antenna range. Front to rear performance is an outstanding aspect of this antenna. The SteppIR 3 element yagi has rated front to rear ratios of 20 - 35 dB on 20, 17 and 15 meters, and 10 - 20 dB on 12 and 10 meters. Front to rear is the response from the back of the antenna at it’s least favorable point. Front to back, on the other hand, is simply the response of the antenna at exactly 180 degrees. In many cases this is not the worst case response from the back of the antenna. We feel that specifying front to rear measurement is much more useful to our customers. Also, keep in mind that front to back varies with the angle of arrival of the particular offending signal. In some cases, you may find front to back exceeding 20 - 35 dB, but it will never be less than that.

How resistant to corrosion is the conductive strip?

The conductive strip is special blend of copper beryllium, specially manufactured to factory specifications. This type of copper beryllium has been used for continuous exposure undersea saltwater applications, where product life exceeded 30 years. It was soaked it in brine for 60 days alternating with air exposure and then checked  for connection resistance . It was found that with one pass under the brushes or 6 volt applied, a very low impedance connection was observed. The tape is designed for upwards of 1 million cycles, as long as it does not exceed its stress point, which the designers were very careful to ensure.

What is the Transceiver Interface?

The transceiver interface allows the SteppIR antenna to communicate with your rigs output port. When this function is selected, the antenna will automatically adjust its length as you tune through the bands. This feature is available on all the SteppIR antennas as an option. Currently, the controller is set up to work with Yaesu,  ICOM and Kenwood transceivers with the output port option.

How well will the antenna handle extreme weather conditions (wind, heat, ice)?

The SteppIR antenna is rated from -20 deg F to 130 degrees F. The antenna is made entirely of corrosion resistant products (stainless steel, aluminum, fiberglass and thermoplastics). The conductive elements are protected by the fiberglass support tube, and the entire unit is sealed & vented. The SteppIR is wind rated to 80 mph. We have designed the SteppIR to work trouble free in all weather conditions within the parameters of it’s environmental specifications.

Is the SteppIR dipole upgradeable to a 2,3 or 4 element yagi?

The element expansion kits allow you to convert our dipole to a yagi, depending on your situation. Each kit consists of elements and the appropriate boom sections required for converting the dipole to a 2 or 3 element yagi.. The electronic controller does not need to be changed. It can control any antenna version with just a software upgrade. Antenna control cable is available for purchase, but is not included in the element expansion kit.

Is the SteppIR antenna available as a vertical?

Yes! BiggIR and SmallIR are available. Keep reading on!

What is a BoomSlide?

The BoomSlide™ is a device that attaches temporarily to the boom to mast plate and has wheels on it that allow you to slide the 16 foot boom securely all the way from one end to the other. The BoomSlide makes it very easy for one person to install the antenna while up at the top of a tower, tree or? It's not free… but it is much cheaper than all the beer and pizza you would have to buy for your average antenna party!!

Could you explain the matching system for the yagi?

The matching system is a very broadband transmission line transformer designed by W2FMI. This balun includes a 22 to 50 ohm UNUN as well, to match Yagis that are in the 20 to 25 ohm impedance range with a very low VSWR. We chose 22 ohms because that is the impedance of practical yagi’s that exhibit very good gain and front to back ratios. Since each element  is controlled very preciselyYagis are 22 ohms. If you want more gain, you could change the lengths (in the create antenna mode) and get a lower impedance antenna, if you could live with a little higher VSWR.

Does the entire antenna adjust, or do the poles stay out once extended?

The fiberglass element supports are 4’ (1.2 m) long when collapsed. The fiberglass supports are 18’(5.5 m) in length when fully extended. Each element is made up of two of the fiberglass element supports, for a total element length of 36’ (11 m). The fiberglass element supports remain extended at all times. The conductive copper beryllium strip is on the inside of these supports, and is adjusted to the required length by the stepper motors.

Field Testing

The makers did extensive testing on the SteppIR antenna design. One of these tests was a simulation of the independent studies that were conducted by H. Ward Silver (N0AX) and Steve Morris (K7LXC). These tests are intended to evaluate the performance of a given antennas forward gain as compared to that of a dipole, as well as it's SWR front to back ratio and relative SWR.

The tests started by placing a reference dipole at one end of an antenna range and a receiving dipole at the other, with both antennas being of an equal height of 48'. From the reference dipole station a 100 watt CW signal was transmitted via an Icom 706 transceiver to the receiving dipole, with the signal strength characteristics being recorded by an HP 141-T spectrum analyzer. This was done for each frequency to be tested. SWR measurement was accomplished with a Bird model 4391 RF Power Analyst. The reference dipole was then replaced with the SteppIR Yagi test antenna. The two antennas were on level terrain, separated by a distance of 705 feet. A CW signal was transmitted from from the SteppIR Yagi, beamed directly at the receiving dipole, with the HP 141-T acting as the "receiver". The differential between the recorded gain of the reference dipole and that of the SteppIR Yagi (in the exact same conditions) determined actual forward gain at a given frequency. Front to rear test were also performed . Front to rear is the response from the back of the antenna at it’s least favorable point. Front to back, on the other hand, is simply the response of the antenna at exactly 180 degrees. In many cases this is not the worst case response from the back of the antenna. Specifying front to rear measurement is much more useful to our customers. Also, keep in mind that front to back varies with the angle of arrival of the particular offending signal.


Remotely controlled - Bandchanging antennas - BiggIR and SmallIR.

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Verticals are available that cover 40 meters through 6 meters by using coils, traps, capacitors or linear loading, but do so at the expense of significant performance reduction. With the addition on the WARC bands on 30m, 17m and 12m, multi-band vertical antenna performance has clearly become a challenge. 80m is now an add-on option for the BigIR. The 80m coil option provides for 4 user-selectable points within the 3.5-4.0 MHz range, and consists of a module that bolts on to the BigIr vertical - see below. An additional 4-core cable is required to control the 80m coil. Contact us for more details.

A vertical antenna that is precisely adjustable in length while in the air solves the coverage problem, and in addition has vastly improved performance over existing fixed length verticals. The ability to tune the antenna to a specific frequency results in excellent performance on every band - and this means the entire band, with very low VSWR. Resonant antennas must be made a specific length to operate optimally on a given frequency. So, instead of trying to "trick" the antenna into thinking it is a different length, why not just change the antenna length? This is what we have done with the new SteppIR verticals.

Each vertical antenna consists of one spool of flat copper strip conductor mounted in the antenna housing. The copper strip is perforated to allow a stepper motor to drive it with a sprocket. Stepper motors are well known for their ability to index very accurately, thus giving very precise control of the antenna lenght. In addition, the motors are brushless and provide extremely long service life.

The copper strip is drive out into a hollow, lightweight fiberglass support element. This telescoping support element stays extended at all times, while the conductive strip is adjusted to the exact required length using the microprocessor based controller (via 22 gauge, 4 conductor shielded control cable). The antenna is easy to assemble and is extremely portable.

Specifications BiggIR SmallIR
Weight 15 lb / 6.8 kg 12 lb / 5.44 kg
Max. wind surf. area 1.9 ft2 / 0.17 m2 1.0 ft2 / .09 m2
Guyed wind survival (w/ 2 guys@8') 80 MPH 100 MPH
Un-Guyed wind survival 50 MPH 100 MPH
Element Length 32 ft. / 9.75 m 18 ft. / 5.49 m
Maximum power 2000 W PEP 2000 W PEP
Frequency coverage MHZ 6.9 - 54.0 13.8 - 54.0
Cable Requirements 4 cond shielded .4 cond shielded
Tuning Rate 1.17 Mhz / Second 1.17 Mhz / Second
Grounding System Required? * Yes * Yes
Feed Type End fed End fed
Wavelength 1/4 1/4
Price £ sterling inc VAT Please call Please call

* Minimum recommended grounding system :

At Ground Level : eight 0.1 wavelength radials cut to the lowest frequency of operation (14 ft at 7 MHZ, 8 ft at 13.8 MHZ) as close to ground level as possible

Above Ground : two radials cut to the specific frequency for each band of operation (insulated wire recommended)

Grounding system can be as complex as traditional radials, or as simple as a hotel balcony railing!

*Minimum recommended grounding system :

At Ground Level : eight 0.1 wavelength radials cut to the lowest frequency of operation (14 ft at 7 MHZ, 8 ft at 13.8 MHZ) as close to ground level as possible

Above Ground : two radials cut to the specific frequency for each band of operation (insulated wire recommended)