SteppIR 3 Element Yagi User manual

3 Element Yagi Instruction Manual
Revision 3.0 Sept 2012
2112 116TH AVE NE SUITE 1-5, BELLEVUE WA, 98004 WWW.STEPPIR.COM TEL: [phone] FAX: [phone]

SteppIR Antennas - 3 Element 2
Topic Page
3 El Yagi component check 3
Assembly kit materials lists 4
SteppIR acronyms 5
SteppIR “Why Compromise” 6
SteppIR design 7
Assembling the boom 8
Element spacing and position drawing 9
EHU wiring 10
Wiring the DB25 dSub splice 11-12
Connect the boom to the mast plate 13
Determining the direction of the antenna 13
Secure the lids to the EHU housings 14
Attaching Element Housing to the mounting plate 15
Connecting control wiring 16-19
Optional Connector Junction Box wiring schematic 18
Preparing telescoping fiberglass poles 20
Polyolefin heat shrink installation 21
Foam plug assembly for telescoping pole tips 22
Connect the telescoping poles to the EHU 23
Optional 6m passive element kit 24
SteppIR performance 25-28
SteppIR optional equipment 29-30
Limited warranty 31
Yagi specifications 32

SteppIR Antennas - 3 Element 3

SteppIR Antennas - 3 Element 4
Assembly Kit Materials List
QTY PART NUMBER DESCRIPTION
1 70-1102-21 Terminal Housing 1.5”
1 60-6000-35 3” HOSE CLAMP
1 20-6020-12 12-POSITION TERMINAL STRIP
1 20-6020-01 1-POSITION TERMINAL STRIP
1 10-1029-01 PACKAGE CONNECTOR PROTECTOR
3E Connector Pack
72-0016-02
QTY PART NUMBER DESCRIPTION
260-0003 1-3/4” U-BOLT & SADDLE
260-0004-21 2” LONG U-BOLT & SADDLE
360-0062 2-3/4” x 1/4” BOLT
360-0030 1/4” NYLOK NUT
860-0046 5/16” NYLOK NUT
15 60-0041 1/4 WASHER
3E Element Fastener Pack
72-0005-01
QTY PART NUMBER DESCRIPTION
11 60-0019 10-32 Nylock Nut
260-0017-10 10-32 X 7/8 Flat Phillips Screw
960-0061 10-32 X 7/8 Pan. Phillips Screw
11 60-0018 10-32 Flat Washer
EHU Lid Hardware Kit
72-0054-01
Note: There are three sets of this kit for the 3 Element Yagi

SteppIR Antennas - 3 Element 5
Abbreviations
EST Element Support Tube
EHU Element Housing Unit
QD Quick Disconnect Boot (rubber)
QD
EHU
EST

SteppIR - Why Compromise?
The SteppIR antenna was originally conceived to solve the problem of covering the six ham
bands (20m, 17m, 15m, 12m, 10m and 6m) on one tower without the performance sacrifices
caused by interaction between all of the required antennas.
Yagis are available that cover 20 meters through 10 meters by using interlaced elements or
traps or log periodic techniques, but do so at the expense of significant performance reduction
in gain and front to back ratios. With the addition of the WARC bands on 17m and 12m, the use
of interlaced elements and traps has clearly been an exercise in diminishing returns.
Obviously, an antenna that is precisely adjustable in length while in the air would solve the fre-
quency problem, and in addition would have vastly improved performance over existing fixed
length yagis. The ability to tune the antenna to a specific frequency, without regard for band-
width, results in excellent gain and front to back at every frequency.
The SteppIR design was made possible by the convergence of determination and high tech
materials. The availability of new lightweight glass fiber composites, Teflon blended thermo-
plastics, high conductivity copper-beryllium and extremely reliable stepper motors has allowed
the SteppIR to be a commercially feasible product.
The current and future SteppIR products should produce the most potent single tower antenna
systems ever seen in Amateur Radio! We thank you for using our SteppIR antenna for your
ham radio endeavors.
Warm Regards,
Mike Mertel
Michael (Mike) Mertel - K7IR
President
SteppIR Antennas - 3 Element 6

SteppIR Antennas - 3 Element 7
SteppIR Design
Currently, most multi-band antennas use traps, log cells or interlaced elements as a means to cover sev-
eral frequency bands. All of these methods have one thing in common–they significantly compromise
performance. The SteppIR™ antenna system is our answer to the problem. Yagi 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 perform-
ance 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 flat copper-beryllium tape conductor (.54” Wide
x .008” Thick) mounted in the element housing unit. The copper-beryllium tape is perforated to allow
a stepper motor to drive them simultaneously with sprockets. Stepper motors are well known for their
ability to index very accurately, thus giving very precise control of each element length. In addition,
the motors are brushless and provide extremely long service life.
The copper-beryllium tape is driven out into a hollow fiberglass elements support tube (see below),
forming an element of any desired length up to the limit of each specific antenna model (a vertical uses
only one side). The fiberglass elements support tubes (poles) are telescoping, lightweight and very du-
rable. When fully collapsed, each one measures approximately 57” in length. Depending on the
model, there may be additional extensions added to increase the overall element length.
The ability to completely retract the copper-beryllium antenna elements, coupled with the collapsible
fiberglass poles makes the entire system easy to disassemble and transport.
The antenna is connected to a microprocess or-based controller (via 22 gauge conductor cable)
that offers numerous functions including dedicated buttons for each ham band, continuous
frequency selection from 80m to 6m (depending on the model). There are also 17 ham and 6
non-ham band memories and you can select a 180° direction reversal* or bi-directional*
mode and it will adjust in just about 3 seconds (* yagi only).
Boom
Element Housing Unit
Element Support Tube
Stepper Drive Motor
Copper Beryllium Tape
Copper-Beryllium Tape

3 element Yagi Installation
Note: If you have the 40m - 30m dipole kit some of the standard 3 element assembly parts will also be in
this box.
It is much easier to put the antenna together right than figure it out what you did wrong after it is up
in the air. The 3 element SteppIR Yagi boom consists of four sections of aluminum tubing that are 4 feet
long x 1-3/4” OD x 1/8” wall, along with three aluminum element mounting brackets as shown in Figure
1. The element mounting brackets are pre-installed at the factory. To assemble your antenna, you will
need a 1/2” (13mm) and 7/16” (11mm) wrench and / or socket drive. We double check the fasteners for
proper tightness before shipping but it is always a good idea to check them yourself before installing the
antenna. Put anti-seize grease on all bolts 1/4” or larger, especially on the u-bolts because it greatly in-
creases their gripping power. Anti-seize grease (molybdenum based) is available at most auto part stores.
Assemble the boom & connect to mast plate
The boom is completely assembled and drilled at the factory to assure precision element alignment. You
may notice in some cases that on a given splice (Figure 1.5) the holes on each side of the splice are at 90
degrees with each other. This is as designed and not a mistake. Pre-drilled holes are quite snug to align
almost perfectly. In some cases you may find it necessary to assist the bolts with a tap of a hammer, or
“thread” them in by turning with a wrench. If the holes are visibly out of alignment when you are assem-
bling the boom, you probably have the boom pieces put together in the wrong order - or the section of
booms without an element to boom bracket may need to be rotated 180 degrees. Each boom piece has a
number permanently written, scribed or stamped on it. Match each number with the exact same number
of a corresponding boom piece. Figure 1.5 shows joint # 1 markings inside the ring (they must line up).
Drawing 2A shows how each boom section is numbered.
Connect the boom by sliding the respective sections together and align the pre-drilled holes (Figure 2 and
3). Refer to Figure 5 and Drawing 2A for correct configuration. It is advisable to spray a small amount of
WD-40 on the male sleeve before sliding the female section onto it. Do not twist the aluminum exces-
sively, as this can cause binding - the WD-40 will help keep the two pieces lubricated. Insert the included
bolts into the pre-drilled holes, and tighten the Nylok nut securely (Figure 4). Be sure to position the bolts
and nuts so that they are in the same direction as the others. Make sure the boom bolts for the center
splice are installed as shown in Figure 8, if you install them the opposite way the bolt will interfere
SteppIR Antennas - 3 Element 8
Figure 2 Figure 4 Figure 3
Figure 1.5
Figure 1

SteppIR Antennas - 3 Element 9
2 2 3 31 1
Splice Splice Splice
Optional 6m Passive
112 in. Long
Director Driven Reflector
89.5 in. 102.5 in.
31 in. From center of driven element
to center of 6m passive element
3 Element Yagi Spacing
and Installation Layout
(not to scale) Boom / Mast Plate
Mast 40m - 30m Return
Mounting Bracket
DRAWING 2A
Note: Element spacing is measured from element center line to element center line in all cases - not from
the brackets or element housing units.
The four sections of a 3 element yagi shown in the staggered order of installation
Figure 5
Director
Driven
Reflector
Return

SteppIR Antennas - 3 Element 10

SteppIR Antennas - 3 Element 11

SteppIR Antennas - 3 Element 12
CONNECTING THE CONTROL CABLE TO THE D25 SPLICE

Connect the Boom to the Mounting Plate
The mast plate has a total of eight pre-drilled holes. Four are used for the 2” stainless steel mast
clamps and four more are used for the 1-3/4” stainless steel boom clamps.
Connect the mast to the mast plate using the included 2” stainless steel U-Bolts, with saddles, and Ny-
lok nuts as shown in Figure 7. Tighten securely.
Note: If you are doing this on the tower it is advisable to test each U bolt for a proper fit and
bend if necessary to ensure ease of assembly on the tower.
Connect the boom to the mounting plate on the opposite side of the mast ( Figure 7 and 8), using the 1-
3/4” U bolts, saddles, and nuts. Align the boom so that the element brackets are level, then tighten se-
curely. The center balance point of the boom is at a splice, as shown in Drawing 2A. There will be a
bolt on each side of the splice - make sure that the nut end of these two bolts are facing away from
the mast plate (Figure 8). Otherwise, you will not be able to secure the boom snugly to the boom
clamps. To ensure a balanced weight load, the center of the mast plate should be reasonably close to
the center balance point of the boom.
Determining the direction of the antenna
The SteppIR Yagi has three “directions” in which it can be used. Normal, 180 degree and bi-
directional. This can make it complicated to describe the actual “aiming” direction of the antenna!
When you are installing the Yagi, you will want to position the antenna so that the “normal” direction
coincides with your rotor heading. When you are in normal direction, the forward, or “aiming” element
is a director, and the element behind the driven is a reflector. In the normal direction, the director is the
element that is closest to the driven element (89.50” between the two). In the 180 degree mode, we
swap the reflector and director positions by changing their respective lengths. However, we do not
simply swap the actual element lengths, we create a new antenna based on the new element spacing.
So you will always have an optimized antenna.
SteppIR Antennas - 3 Element 13
Figure 7 Figure 8
Figure 6
2” Mast
2” Mast
1-3/4 Boom 1-3/4 Boom

SteppIR Antennas - 3 Element 14

Attach the antenna housing to the element-to-boom bracket
Place the flat side of the element housing unit (EHU) on top of the element boom brackets (Figure 9).
Note: If the mounting holes for the element housing do not line up with the holes in the element
bracket it may be necessary to loosen the two horizontal bolts that hold the element bracket to
the boom . After mounting the element housing to the element bracket be sure to re tighten the
two horizontal bolts.
The housings without the SO-239 coax connector are the director and reflector (they are identical and
interchangeable), the one with the SO-239 connector is the driven element (the balun is on the inside
of this housing). The reflector and director should be positioned so the actual fiberglass element is fur-
thest away from the driven element (Figure 10). The driven element should be positioned so that the
element is closest to the mast plate (Figure 11). Fasten each element housing to the element bracket,
using eight 10-32 x 7/8” screws, flat washers, Nylok nuts. The flat washer needs to be placed be-
tween the screw head and the plastic element housing. Tighten securely, but not too tight (if you
over-tighten the nut, you may split the plastic flange on the element housing). The olive green element
support tube (EST) on each antenna housing will appear uneven in length - it is actually centered on
the inside of the antenna housing .
Note: The reflector element and the driven element will have the EST (offset tube) lined up so that
the short side and long side of the each EST are facing in the same directions. The director
element EST configuration will be the opposite. This is normal.
SteppIR Antennas - 3 Element 15
Figure 11
Figure 9 Figure 10

SteppIR Antennas - 3 Element 16
Connect the wiring and secure to boom
WARNING: Make sure the 25-pin sub-D connector is not connected to the controller if the 24 VDC
supply is energized and plugged into the controller. There are voltages present on the
control cable wires even when the power button on the controller has been pushed to
“off”. Shorting the control wires with power on them will destroy the driver chips. Ei-
ther unplug the 24 volt power supply or disconnect the 25-pin sub-D connector before
making any connections or cutting or splicing the cable.
Also be aware that if you have more than 200’ of control cable you must use our optional 33 VDC
power supply. This will then allow up to 500’ of control cable with no problems.
Be sure to connect the controller case to your station ground using the #8-32 lug on the back of the
controller. This is important for RFI immunity as well as lightning protection. If you are in a high
lightning area take the appropriate precautions the controller can be damaged by lightning. (it is be-
yond the scope of this manual to cover all of the complexities of lightning protection, see some of the
ARRL publications that address this) The surest protection is to disconnect the 25-pin sub-D connec-
tor and power supply, then move them well away from the controller.
There will be a 12 position terminal strip included with the antenna, and a single position terminal
strip for the ground connections as shown in Figure 13 and 14 (the terminal strips are inside of the in-
cluded PVC connector housing, with a white plastic cap loosely attached). First, dip each bare wire
into the provided blue connector protector pouch. Connect each wire of the 4 conductor cable to it’s
respective location on the 12 position terminal strip (Drawing 1 and Figure 14). You will need to re-
peat this on the opposite side of the terminal strip for the 12 conductor cable as well. Each cable (all 3
of the four conductor cables and the 12 conductor cable) will have a bare silver wire, which is the
ground. You will need to connect all three of these to the single terminal strip (Figure 14, Drawing
1A).
Figure 13

When the connections have been secured, you will want to position the cables so that they are parallel
with the 12 position terminal strip (Figure 15). The 12 conductor cable will be at one side, and the 3
four conductor cables will be at the other. Slide the cables and terminal strips into the provided plastic
enclosure (Figure 16), position the cutout in the threaded cap over the cables and screw the enclosure
onto the cap.
Figure 14
SteppIR Antennas - 3 Element 17
Warning: Look carefully at the order of the elements on the terminal block. They are not intui-
tively laid out as they appear on the boom. (we did it to make the ‘2 Element’ wires
consecutive)
Figure 15 Figure 16

SteppIR Antennas - 3 Element 18
OPTIONAL CONNECTOR JUNCTION BOX WIRING LAYOUT*
*This drawing is here for your convenience—refer to the actual accessory Connector Junction Box instructions for
more detail.

Attach the wiring enclosure and control cable to the boom or mast
Position the plastic enclosure in a convenient position on the boom or mast making sure that the cut
out in the cap is facing downward (Figure 18). We do not seal the enclosure so that in the event there
is water accumulation inside the enclosure from condensation, it will be able to escape. Fasten the en-
closure to the boom using the screw clamp, taking care to not trap the cables in between. Tape the ca-
bles to the boom as shown in. The terminal housing mounting location is not critical. It can be
mounted out on the boom or even vertical on the mast what ever works best for your instalation.
Note: Be careful NOT to tape the cables over a sharp edge unless you provide extra protection to pre-
vent eventually cutting through the sheath and shorting the wires.
SteppIR Antennas - 3 Element 19
Warning: We strongly recommend that you perform the “Test Motor” procedure at this point
to verify the wiring is correct and the elements are in the right location. If you are
not going to connect the control cable and test it on the ground make sure you have
the element control cables positively identified and well marked. If you get the ele-
ments mixed up on the terminal block you will get very confusing results such as,
high SWR, low performance, etc. Mark the cables coming from each element box
with colored electrical tape or a felt pen. Mark them before you tape them along the
boom, it is very easy to get two parallel wires mixed up. Now when you are on the
tower it will be easy to identify each element control cable positively.
Figure 19
Rotor Loop:
Control cable and coax
taped together
Tape to boom approximately
8” from coax connection
Suggested Coax Routing
Figure 18
Mount Horizontal or Vertical

SteppIR Antennas - 3 Element 20
Prepare the Fiberglass Element Support Tubes (standard poles)
Note: If you have ordered the optional 40m - 30m Dipole Kit you need to refer to the section on
preparing the poles (ESTs) in that specific manual. The 4 special poles for this option
have some differences from the standard poles.
Locate:
 Dark green fiberglass telescoping poles (Figure 20)*
 Six black rubber boots with clamps
 Your tape measure
The green fiberglass poles are all assembled in the same manner, and when extended, become element
support tubes (ESTs) for the flat strip copper beryllium elements themselves. The copper-beryllium
strips are shipped retracted inside their respective element housing units (EHUs).
Repeat the following procedure for each telescoping pole
Telescope a pole to full length by pulling each section out firmly in a twisting motion until it is ex-
tended as far as possible. Each segment is tapered and should lock securely in place when fully
extended. Pole lengths may vary but, when fully extended, each pole must be at least 17 feet 8
inches in length as measured from the butt end of the pole to the tip (Figure 20). Verify the length
for each pole before installation or heating the joints.
If a pole comes up a little short (1/2” to 1”) try collapsing the pole and starting over, this time aggres-
sively “jerk” each section out instead of twisting. The pole cannot be damaged and you may gain a
minimum of 1/2” or more. If you have trouble collapsing the pole try carefully striking one end on a
piece of wood or other similar surface placed on the ground.
Figure 20
17’ 8” min
Rubber Boots