Logo SteppIR

SteppIR Antennas

SteppIR manufactures freely tuneable multiband beams with 2, 3 or 4 elements for 40 to 6m or 20 to 6m. With the continous mechanical tuning of the element lengths SteppIR Yagis achieve the performance of comparable monoband beams - but on many bands. The similiar contructed λ/4 verticals offer always perfect match as tuned groundplane. The small packing size and the lightweight construction with glassfibre tubes makes these antennas an ideal companion for dx-peditions and fielddays.

The problem with traditional beams

Traditional multiband beams require traps, interlaced elements etc. to work on multiple bands. With these elements such an antenna is usually a compromise in respect to the possible maximum efficiency of an antenna. Monoband beams like the ZX Yagis would be an alternative, but who can put up three or more such beams?

The idea: variable lengths elements

FluidMotion, the manufacturer of SteppIR antennas has solved this problem in an elegant way. SteppIR vary the mechanical length of each element by means of a retractable metal band. This allows the antenna to be adjusted for any frequency (within the range) and work near the perfect optimum.

Contruction of a SteppIR

Each element of a SteppIR antenna consists of lightweight glassfibre tubes, the metallicc band run in these tubes. That means of course that the absolute size of the antennas does not change, the glasfibre tubes are not changed in length. The metallic bands are made of a special Copper Beryllium (CuBe) which withstands millions of movements. The excellent electrical contact is achieved with four self cleaning slider contacts for each element. The metal band itself is perforated, a sprocket wheel spools up the band. The sprocket is driven by a precision stepper motor, allowing for very precise positioning.

Bild SteppIR 2-element


Each single element is controlled by a 4 wire cable, i.e. the 4-element SteppIR yagi requires 16 wires. Down in the shack a supplied controller is used to adjust the antenna. For the amateur bands various presets are available for each band. Further a "general" mode allows adjustment of the antenna to any frequency (within the specified range). Antenna setups can be stored for later recall, other functions allow the quick reversal of direction or the bi-directional mode where the gain is evenly distributed in two directions. An optional CAT interface for the controller allows direct control from most amateur rigs: the antenna is continously adjusted when the frequency on the rig is changed.

Optional 30/40m Radiator

This replaces the standard radiator and allows operation down to 40m. Available in two version: one as option when buying a new antenna and one as replacement part for an existing antenna.

Technical data and comparison table

  Dipol 2 Element Yagi 3 Element Yagi 4 Element Yagi DB-11 DB-18 DB-18E DB-36 DB-36
with 80m
DB-42 DB-42
with 80m
Frequency range (continous) 13,8 - 54 13,8 - 54 13,8 - 54 13,8 - 54 13,8 - 54 6,8 - 54 6,8 - 54 6,8 - 54 3,5 - 54 6,8 - 54 3,5 - 54 MHz
Max. Power 3 3 3 3 3 3 3 3 3 3 3 kW
Weight 4,5 13,6 19,0 34 28.6 41.2 45.3 72.8 74.4 108 109 kg
Antenna surface 0,17 0,37 0,57 0,90 0.54 0.9 1.1 1.63 1.63 1.85 1.85
Max. Wind speed ~ 160 ~ 160 ~ 160 ~ 160 ~ 160 ~ 160 ~ 160 ~ 160 ~ 160 ~ 160 ~ 160 km/h
Longest Element 10,97 10,97 10,97 10,97 5,79 11,88 11,88 14,9 14,9 14,9 14,9 m
Rotating radius 5,48 5,53 6,00 7,35 3,20 6,50 6,50 8 8 8,8 8,8 m
Boom length - 1,44 4,87 9,75 3,35 5,80 5,80 10,97 10,97 10,97 10,97 m
Boom diameter - 4,5 4,5 4,5 & 5,7 4,45 5 5 4,5-6,35 4,5-6,35 13 13 cm
Max. Mast diameter 53 53 53 53 53 53 53 53 53 53 53 mm
Required Control cable 4 8 12 16 16 16 16 16 24 25 25 Wires
Balun incl. No (optional) Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes  
Order No. 12100.1 12100.2 12100.3 12100.4 12113 12115 12115.E 12116 12116.80 12117 12117.80  
Price 1392.00 € Buy now 1839.00 € Buy now 2471.00 € Buy now 3564.00 € Buy now 3760.00 € Buy now 3980.00 € Buy now 4960.00 € Buy now 7299.00 € Buy now 7015.00 € Buy now 8280.00 € Buy now 9199.00 € Buy now
Order No 6m Option     12100.63 12100.64   12100.63 12100.63          
Price     107.00 € Buy now 107.00 € Buy now   107.00 € Buy now 107.00 € Buy now         Euro
Order No. incl. 30/40m Dipole   12105.2 12105.3 12105.4                
Price   2432.00 € Buy now 3046.00 € Buy now 4072.00 € Buy now               Euro

1 According to the manufacturer operation on 30m may require a tuner.

Delivery time of SteppIR Yagi antennas is about 8 weeks.

SteppIR Dipoles and Yagis

The SteppIR Dipole and Yagis are available in five different versions, from one to 4 elements, covering different ranges. Each element is variable in length by using a motor driven metal band (Copper Beryllium). The metal band is protected by a glasfibre tube, the length of this tube does not change of course.

Like with all SteppIR antennas the glassfibre tubes have to assembled and isolated at first set up. This makes the SteppIR antennas very compact, that nice for shipment cost and expeditions.

Variable element length, but fixed element distance?

One of the most frequently asked questions is "Shouldn't the distance of the elements also change when changing element lengths?". To answer this question it is important to understand that Yagis can be designed to maximise different values. That can be max. gain, best Front/Back ratio, good bandwidth etc. But - these goals cannot be achieved all at once with the same design. Either you optimize a yagi for best gain, useful bandwidth and not so good F/B ratio. Or excellent F/B ratio at narrow bandwidth and mediocre gain etc. etc.

With a 3-element beam the optimum gain would be reached at a boom length of 0.4 λ. The best F/B ratio is achieved with a boom length of approx. 0.25 λ, but only at limited bandwidth. This results in 0.3 λ as a good compromise, with this it can be shown that a variable element length results in much greater effect than variable distance. Bandwidth is of no importance with a SteppIR antenna because the antenna can be adjusted to any operating frequency (within specified range). So a narrow bandwidth design can be selected which results in the best compromise solution at a given element distance. That is much more than what you can expect from a traditional monobander.

Bild SteppIR 3-Element

Gain and Front/Back ratio

  • G: Gain [dBi]
  • FBR: Front/Back Ratio [dB]
  Dipol 2 Elem. Yagi 3 Elem. Yagi 4 Elem. Yagi 4 Elem. Yagi MonstIR DB-11 DB-18 DB-18E DB-36 DB-42
40m - - - - - - - - 7,8 25 - - 6,2 20 6,2 20 7,2 221 8,8 25,5
30m - - - - - - - - 8,2 20 - - 5,4 - 7,0 20 8,2 18 9 12,4
20m 2,1 0 4,2 18 5 42 9,5 21 9,5 21 6,4 19,5 7,4 25 7,4 25 9,3 22 10,1 22
17m 2,1 0 4,2 19 5,5 44 10 20 10 20 6,1 16,2 8,3 25 8,3 25 9,9 27 10,8 22
15m 2,1 0 4,1 14 5,7 44 10,2 27 10,2 27 7,1 21,4 8,5 20 8,5 20 10,2 27 11 25,7
12m 2,1 0 4,0 13 6,2 17 10,4 21 10,4 21 7,3 23,2 8,8 15 8,8 15 10,4 21 11,9 24,1
10m 2,1 0 3,8 10 6,3 15 10,6 11 10,6 11 7,5 24,55 9,0 11 9,0 11 10,7 11 12,2 20
6m 2,1 0 2,6 1,5 3,0 4 7 7 7 10 8,7 15,1 6,2 4 6,2 4 4 2 4 2
  • Gain in dBi (Free space)
  • F/B ration in dB. The manufacturer denotes this value as "Front/Rear" and refers to the max. achieveable bakwards attennuation, whose maximum is not necessarily in the -180° direction.
Order No.
12100.1 SteppIR Dipole 20-6m with controller delivery time about 8 weeks 1392.00 € Buy now
12100.2 SteppIR 2-Element 20-6m Yagi with controller delivery time about 8 weeks 1839.00 € Buy now
12100.3 SteppIR 3-Element 20-6m Yagi with controller delivery time about 8 weeks 2471.00 € Buy now
12100.63 6m Option for 3-elem. Yagi 107.00 € Buy now
12100.4 SteppIR 4-Element 20-6m Yagi with controller delivery time about 8 weeks 3564.00 € Buy now
12100.64 6m Option for 4-elem. Yagi 107.00 € Buy now
12105.2 SteppIR 2-elem. with 30/40m Radiator delivery time about 8 weeks 2432.00 € Buy now
12105.3 SteppIR 3-elem. with 30/40m Radiator delivery time about 8 weeks 3046.00 € Buy now
12105.4 SteppIR 4-elem. with 30/40m Radiator delivery time about 8 weeks 4072.00 € Buy now
12142 CAT interface for controller 125.00 € Buy now
12146 Y-cable for CAT 66.00 € Buy now
12155.RUBBER Spare part Rubber sleeve on EHU 9.90 € Buy now
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SteppIR Dream Beam DB-11

SteppIR DB-11 Beam SteppIR DB-11

The DB-11 is the smallest beam of SteppIR Yagi antenna which uses the loop technology. This allows the full performance can be achieved despite a 40% smaller area.

The DB-11 has an integrated coaxial switch that selects which is the radiator of the 3 elements in order to ensure the same performance in both directions. The control of the switch is integrated into the control unit SDA 100. The DB-11 is the only 6m antenna without optional element, because the distance of the 3 elements to each other is ideal for operating in this band.

SteppIR DB-11 Beam SteppIR DB-11

With two active elements on 20m and 3 semi-active elements on 20m, the average gain is 7 dB and the front / back ratio 20dB per band.

Order No.
12113 SteppIR DB-11 3760.00 € Buy now New
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SteppIR Dream Beam DB-18, DB-18E

SteppIR DB-18 Beam SteppIR DB-18

The DB-18 beams by SteppIR extend the well known antenna principle with variable length elements. With the previously existing SteppIR Beams the 30/40m element was the only element for these bands, resulting in no gain compared to a dipole. The Dream Beam uses 2 (DB-18) or 3 (DB-18E) such folded elements to achieve a gain and good front/back ratio also on 30 and 40m.

Both antennas, the DB-18 and the DB-18E, offer an automatic selection of the driven element, depending on frequency and 180° reversal. This is because shortened elements don't work well as directors, so the radiator is switched from the center element to one of the outer elements. The other two elements act as refelectors in this case.

SteppIR DB-18E Beam SteppIR DB-18E

The switching of the feedline is done with a solid 5KW, 3 port antenna switch. The switch and the required cables to each element are included in the shipment. The selection is done automatically by the new SDA-100 controller, which is included with these antennas. Both Dream Beam antennas require a control cablw with 16 wires (3x4 for elements, 1x4 for switch).

Order No.
12115 SteppIR DB-18 3980.00 € Buy now
12115.E SteppIR DB-18E 4960.00 € Buy now
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SteppIR Dream Beam DB-36, DB-42

SteppIR DB-42 Beam SteppIR DB-42

SteppIR DB-36
In the series of large antennas by SteppIR we offer two new models. The DB-36 has the dimensions of a conventional multi-bandyagi and is still always a mono-band beam. In addition to those already contained bands from 6m to 40m, this antenna can be increased with a 80m option.

SteppIR DB-42 (MonstIR PRO)
The world's largest Yagi antenna with a dynamic system. The DB42 has 5 elements on 20m-6m and 3 elements on 40/30. For those who aspire to the top of performance, the DB42 provides a frequency range from 80m to 6m (80m dipole with optional kit). The 6m option adds 3 passive elements without increasing the surface wind. Thus, the DB42 on 6m total of 8 elements with a gain of 14.0 dBi and 25 dB front / back ratio.

Order No.
12116 SteppIR DB-36 7299.00 € Buy now
12116.80 SteppIR DB-36 with 80m 7015.00 € Buy now
12117 SteppIR DB-42 8280.00 € Buy now
12117.80 SteppIR DB-42 with 80m 9199.00 € Buy now
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SteppIR vertical antennas

Bild SteppIR Vertikal

Besides the SteppIR Yagis two vertical are available which work with the same elegant principle. In a vertically mounted glassfibre tube a metal band made of CuBe is extended or retracted. The band is wound with a stepper motor, changing the electrical length of the antenna, without lossy traps, loading coils etc.

This type of antenna of course requires a good radial network (not included). The radial network strongly affects the performance and critical values like radiation angle of the antenna. And especially vertical antennas are known for the low take-off angle, good for DX.

Radials networks can be designed either as elevated radials or ground radials. Elevated radials require tunes lengths at λ/4, at least two per band. Ground radials can be of any lengths, but at least λ/10 in length, the more the better. The operators manual of the SteppIR verticals gives many more useful hints for constructing a good radial network.

Two verticals are available: the SmallIR covers 20 to 6m, the BigIR covers 6m to 40m (with option up to 80m). Technical data see table below. Included with the vertical SteppIR antennas is the SDA-100 controller.

  SmallIR Mk3 Vertical BigIR Mk4 Vertical  
Frequency range (continous) 13,8 - 54 6,9 - 54 MHz
Max. Power 3 3 kW
Tuning Speed 1,17 1,17 MHz/s
Weight 5,44 6,8 kg
Antenna Surface 0,09 0,17 m2
Max. Wind speed ~ 160 ~ 130 km/h
Height 5,49 9,75 m
Required control cable 4 4
8 with 80m coil
Balun included No No  
Order No. 12120.V20 12120.V40  

80m extension coil for BigIR Antenna

80m Option for BigIR

Extension coil for BigIR vertical antenna, enables operation also on the 80m band. Max power load 500W (1600W with new BigIR Mk3). Requires 4 additional wires in the control cable.

Order No.
12120.V20 SmallIR Mk3 Vertical 20-6m 1149.00 € Buy now
12120.V40 BigIR Mk4 Vertical 40-6m 1499.00 € Buy now
12120.V80 BigIR Mk4 Extension only 525.00 € Buy now
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Special offer 'old' controller for BigIR

New, but without firmware chip. List price was 490.- EUR

Order No.
ZG-CB 299.00 € Buy now
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SteppIR Controller

SDA-100: Controller for all SteppIR Antennas

SteppIR SDA-100 Controller SDA-100

The SDA-100 offers an improved lightning protection on the driver circuits, compared to the standard controller. The driver chips are now socketed for easier replacement.
Additionally we offer (optionally) the 'advanced lightning protection' (ALP), with add more protection against lightnings and static discharge.
The CAT control (requires CAT option) can be switched on and off with a button. A blinking LED shows if the antenna is currently tuning or not.


Further details:

  • Additional button to retract the elements
  • Button with LED to show the current direction (normal or 180°)
  • Firmware updates of the SDA-100 are possible over an USB interface; the firmware is available on the SteppIr website
  • Improved and faster manual frequency control
  • Two lines, backlit LC display

Tuning Relay for SDA-100

Tuning Relay Board

Prevents the keying of a power amplifier while the antenna is tuning, avoiding damages to the antenna.

Order No.
12150 SDA-100 without ALP 652.00 € Buy now
12150.ALP SDA-100 with ALP Note: The ALP option can not be retro-fitted. 907.00 € Buy now
12150.TR Tuning Relay Board for SDA-100 124.20 € Buy now
12150.CAT CAT Option for SDA-100 135.00 € Buy now
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CAT Interface Option

CAT Option SDA-100

An option for the controller is a serial CAT interface. With this option the controller can be connected to most radios, the antenna adjustment is following the tuning of the radio. SteppIR does offer suitable cables for most radios. The simultaneous use of the CAT interface for the antenna controller and a logging program requires a "Y" connector (order no. 12146).

  • Cable 12145.I for all Icom rigs with CI-V interface
  • Cable 12145.FT1000 for Yaesu FT-1000MP, FT-1000MPMkV, FT-1000MP MkV Field
  • Cable 12145.FT897 for K2, Yaesu FT-920, FT-897, FT-897D (requires CT-62)
  • Cable 40060.FF serial Cable f/f, for Kenwood TS570, TS870 (requires Kenwood Adapter), TS2000
  • Cable 40060.FFX for Kenwood TS50 (requires IF-10D)
  • Cable 40060.FFX for Yaesu FT-847
  • Cable 40060.MF for Yaesu FT-857 (requires CT-62), FT-897 (requires CT-62)
  • Cable 40060.FF for Yaesu FT-920
  • Cable 40060.MF for Yaesu FT-990 (requires ROM Vers -04 or newer, requires ser. interface)
  • Cable 40060.MF for Yaesu FT-1000D (requires FIF-232)
  • Cable 40060.MF for Elecraft K2 (requires K2 Serial Kit)
Order No.
12142 CAT interface for standard controller 125.00 € Buy now
12150.CAT CAT interface for SDA-100 controller 135.00 € Buy now
12145.I Cable SteppIR - Icom 32.00 € Buy now
12145.FT1000 Cable SteppIR - Yaesu FT-1000MP 19.50 € Buy now
12145.FT897 Cable SteppIR - Yaesu FT-897, FT-920, K2 19.00 € Buy now
12145.TS480 Cable SteppIR - Kenwood TS-480 24.20 € Buy now
MK-ILINK-STE Cable SteppIR - microHAM MK-2 38.50 € Buy now
40060.FF Serial Cable 9pin f/f (suitable rigs see list) 3.00 € Buy now
40060.FFX Serial Cable 9pin. f/f crossover (Null modem, psuitable rigs see list) 3.60 € Buy now
40060.MF Serial Cable 9pin. m/f (suitable rigs see list) 3.60 € Buy now
12146 "Y" adaptor 66.00 € Buy now
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Connector Box

Replaces the supplied terminal strip which is used to connect the wires from the stepper motors to the control wires. Now solderless, very comfortable connection of the single wires from the motor units with plugable strips. An additional Sub-D socket allows easy testing. Waterproof box which is mounted directly to the mast clamp.

Order No.
12148 Connector Box SteppIR 262.00 € Buy now
12148.DB Connector Box for DB-11 / DB-18 262.00 € Buy now
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SubD 25 Adaptor

Adaptor for control cables to 25pin SubD connector. Very practical device for OMs who don't want to solder, or for people who need to change the cable often for experimentation. For each pin of the SubD 25-pin connector there is a screw terminal on the rear of the adaptor. Requires only a simple screwdriver.

Order No.
12149 SubD-25 Screw Terminal Adaptor SteppIR 40.30 € Buy now
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33V Power supply

Replaces the supplied 24V power supply, recommended for cable lengths over 60m.

Order No.
12143 33V Power supply SteppIR 131.10 € Buy now
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Control cables for SteppIr antennas

Each element of a SteppIr antenna requires four control wires. We offer cables with 6, 12 or 16 wires with 0.14mm² or 0.34mm² cross section. This is sufficient for cable lengths up to 20m. For larger distances the manufacturer suggests to use larger diameter wires or use of a voltage booster (optional 33V power supply).

Unfortunately we don't carry 8 wire control cables for this purpose (the 8 wire rotor control cable is too large). Best is to use our 12-wire cable and use only 8 of those wires. Control cables are here.

Order No.
40012.6 6-wire 0,14mm² per Meter 0.80 € Buy now
40012.12 12-wire 0,34mm² per Meter 1.80 € Buy now
40012.16 16-wire 0,34mm² per Meter 2.85 € Buy now
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Troubleshooting guide

Due to the new working principle of the SteppIR antennas it can happen that something is misunderstood or incorrectly asembled. For cases where the antenna is not working as expected, SteppIR offers this document (PDF, english, 120KB) which helps you locating the trouble. ALthough this document was written with 3-ele and 4-ele Yagis in mind it is helpful for any model of SteppIR antennas.

Software Upgrade Kit

SteppIR offers a Software Upgrade Kit for all antenna controllers. This upgradee is mainly adressed to customers who use the passive 6m element and who plan to use the new 30/40m dipole element. The upgrade requires the exchange of the CPU chip (see below).

Among others the following features were added or improved:

  • Moved Band defaults to more common frequencies in the HAM mode.
  • Moved the center frequency to better center the best SWR.
  • Cleaned up messages so they are clearer.
  • Frequency is common between Amateur and General Freq Modes.
  • Changed Band segments so there is one segment per band.
  • Applied changes done in Create Modify to entire band.
  • Added New Options menu.
  • Added 6M passive selection.
  • Added Transceiver Frequency tracking Disable Key.
  • Added Global Frequency Offset adjustment.
  • Added Global SWR correction.
  • Made it possible to program a single button for the Home position.
  • Added 40/30 Dipole selection.
Order No.
12144.2 SteppIR Software Upgrade Kit for 2-Element beam 44.90 € Buy now
12144.3 SteppIR Software Upgrade Kit for 3-Element beam 44.90 € Buy now
12144.4 SteppIR Software Upgrade Kit for 4-Element beam 44.90 € Buy now
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FAQ and more information for SteppIR antennas

F1: When adding the 6m element to a 3-ele (4-ele) SteppIR, what will change in the software?

A1: The 6m option is enabled in the setup menu. SOme controllers might require a software upgrade.

F2: How does the control box for a MonstIR Yagi (40-6m) look like?

A2: Same as for the other antennas. The 30 and 40m band are access via the menu.

F3: When adding the announced 30/40m element to an existing SteppIR Yagi, what is changed at the control box?

A3: A new chip with a new firmware has to be changed in the control box.

F4: How does the windload and weight change when adding the announced 30/40m element to an existing antenna?

A4: The windload increases by 0,2m2 (2 ft2), the weight increases by approx .4kg.

F5: How are the new bands (30, 40m) operated when adding the announced 30/40m elemnt to an existing SteppIR antenna?

A5: Together with the new firmware chip (see Q3) a decal is supplied for the control box.

F6: How does the announced 30/40m element look like? Pictures?

A6: Voila:

F8: What are the longterm experiences with SteppIR Yagis? Especially under severe weather?

A8: SteppIR antennas are in use since about six years (as of summer 2006). In the beginning there were slight problems with the insulation of the glass fibre tubes, but that has been solved.
SteppIR antennas are in use worldwide by radio amateurs and commercial services, also under severe conditions. Just chek the pictures... (click for a larger view).

F9: Other users of SteppIR antennas report a slight "rustling" noise, comning from the elements. Any remedy for that?

A9: The noise is known, it is caused by wind moving the elements slightly. Unfortunately there is no remedy for that, the radiating copper band has to run freely in the glassfibre tubes. The best suggestion is to fully retract the elements when the antenna is not in use.

F10: What is the sag of the elements of a standard (20-6m) SteppIR Yagi? And with the MonstIR (40-6m) Yagi?

A10: The elements of a standard SteppIR yagi (20-6m) have a sag of up to 8" (20cm), the elements of a MonstIR (40-6m) yagi up to 20" (50cm).

F11: Is it possible to install the announced 30/40m dipole element to any other beam (non SteppIR)?

A11: No, the manufacturer strongly discourages this for a whole plethora of reasons. It is not known if any ever tried or succeeded doing so. SteppIR and WiMo do not support installations like that.