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3 Element Yagi Instruction Manual
Revision 3.3 March 2020
K7XH Tree Mounted
3E with 40/30 loop
13406 SE 32nd St, BELLEVUE WA, 98005 WWW.STEPPIR.COM TEL: (425)-453-1910
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Topic Page
3 Element Yagi specifications 2
Component list 4
Assembly kit materials list 5
Helpful abbreviations 6
A note from Mike Mertel K7IR 7
“What do I do now?” Helpful advice from Jim Streible K4DLI 8—9
SteppIR principle of design 10
A word about stainless steel galling 11
Boom installation 12—13
Element housing unit (EHU) wiring overview 14
EHU Wiring 15—16
25 pin dSUB splice installation 17—18
Connect the boom to the mounting plate 19
Determining the direction of the antenna 19
Mounting the EHU’s to the boom 20
Attach the EHU to the element-to-boom bracket 21
Control cable wiring 22—23
OPTIONAL connector junction box wiring 24
Securing the wiring enclosure to the boom 25
Telescoping fiberglass poles 26—27
Heat shrink installation 27
Foam tips for telescoping poles 28
Attaching the telescoping poles to the EHU’s 29
OPTIONAL 6m passive element kit 30
SteppIR Performance 31
A word about fixed element spacing 31, 34
RF Power transmission with the SteppIR Yagi 32
Balun / Matching system 32
Yagi Gain / front-to-rear modeling 33
Stacking two antennas 33
RF power transmission with the SteppIR Yagi 34
SteppIR Options 35—36
Warranty information 37
TABLE OF CONTENTS
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3 ELEMENT YAGI COMPONENT CHECK
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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
2 60-0003 1-3/4” U-BOLT & SADDLE
2 60-0004-21 2” LONG U-BOLT & SADDLE
3 60-0062 2-3/4” x 1/4” BOLT
3 60-0030 1/4” NYLOK NUT
8 60-0046 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
2 60-0017-10 10-32 X 7/8 Flat Phillips Screw
9 60-0061 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
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Abbreviations
EST Element Support Tube
EHU Element Housing Unit
QD Quick Disconnect Boot (rubber)
QD
EHU
EST
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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 frequency 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 bandwidth, 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 thermoplastics, 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
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You have ordered you SteppIR Antenna and are
waiting for delivery. What do you do in the meantime?
1. Go to the SteppIR web site at www.steppir.com and download the latest manual for your antenna,
and also the Operators Manual for the controller.
2. Read the manuals from cover-to-cover ---TWICE! Don’t just read them –Study them, so you are
familiar the terminology used about the antennas and have a good idea of how the antenna is assembled and where the various parts go.
3. As you go through the manuals make notes of any instructions you may not clearly understand,
then call or email for clarifications. It is better to have it all sorted out before you start assembly.
We don’t mind answering your questions beforehand.
4. Now, wait for notification your antenna is being shipped.
Your antenna has arrived!
What is the first thing to do?
1. If the antennas is to arrive on Wednesday----DO NOT plan an antenna party for Saturday!
2. Even if you plan to install the antenna weeks later, the first thing to do is to unpack the antenna
and do a complete inspection. Make sure nothing is missing or has been damaged in shipment.
3. Do a complete inventory of every part, nut and bolt. Yes it takes time, but it also allows you to
notify SteppIR if anything is missing and allow time to get it to you before you start assembly of
the antenna. There is nothing more frustrating than realizing that something is missing, just
hours before you want to install the antenna.
4. Go back to the SteppIR website and download the latest manual. SteppIR constantly is improv-
ing and adding to the manual, so even though your paper instruction manual is going to have all
the data you need, it makes sense to check for the latest updates online. This is especially true
If you purchased the antenna and a period of time has passed between arrival and install dates.
5. Take the controller and power supply out of their wrappings and connect them. The controller
does not have to be connected to the antenna in order to familiarize yourself with it. In fact, it is
best to get familiar with the controller when it is not connected to the antenna. Turn on the controller and read through the Operators Manual again while operating the controller in all it
modes. Go through the menus so you know what each does and how to navigate through the
various menus and functions.
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Your Antenna Has Arrived!
What is the first thing to do?
(continued)
5. When you have finished working with the controller be sure the display indicates “Elements
Home” and the controller has been turned OFF. When the controller is connected to the antenna and the controller is turned back on the next time, it will immediately tune to whatever position the controller was left in last time you were using it, so you want to be sure that position
is HOME.
6. Once the antenna is completely assembled and ready to mount on the antenna tower, use an
antenna analyzer, if you have one, to test resonance of the antenna.. If you don’t have an analyzer, try to borrow one. It will save you a lot of time and worry. Check the antenna on each
band for some sign of resonance within the frequency range. Leave the antenna on the default
frequency and tune the analyzer to see where the dip occurs. It will be somewhere below the
lower band edge on each band with the antenna 3 or 4 feet above the ground on saw horses.
Also, don’t expect to see a 1:1 SWR here, just look for a good indication of resonance.
Once it has been determined this part of the antenna is working correctly do the following: Select the lowest band and establish the dip condition by tuning the analyzer. Do not touch the
analyzer again. Retract the elements and then reselect the same band. The antenna should
come back the very near the same setting. Do this 2 or 3 times on each band. Also, try going
from the band being tested to any other band and back again and observe that the antenna
comes back to the same resonant point. Now you know the antenna is tuning correctly from
band to band and is consistent.
7. When you are ready to use the antenna, if you have purchased the 40/30 loop, be sure to
“enable” the loop in the controller menu, or your antenna will not work on those bands. If you
purchased the 6m option, be sure to enable that as well. When done enabling, save and then
turn the controller off, and back on again.
8. Enjoy the antenna!
73
Jim Streible—K4DLI
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SteppIR Design
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 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 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 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 mod-
el, 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
Boom
Element Housing Unit
Element Support Tube
Stepper Drive Motor
Copper Beryllium Tape
Copper-Beryllium Tape
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From time to time, we get complaints from customers regarding galling of stainless steel fasteners.
Here is an excerpt from the Industrial Fastener Institute's Standards Book:
Thread galling seems to be the most prevalent with fasteners made of stainless steel, aluminum,
titanium and other alloys which self-generate an oxide surface film for corrosion protection. During
fastener tightening, as pressure builds between the contacting and sliding thread surfaces, protective oxides are broken, possibly wiped off and interface metal high points shear or lock together.
This cumulative clogging-shearing-locking action causes increasing adhesion. In the extreme, galling
leads to seizing - the actual freezing together of the threads. If tightening is continued, the fastener
can be twisted off or its threads ripped out.
During minor galling, the fastener can still be removed, but in severe cases of galling, a strong bond
between the bolt and nut can prevent removal of fasteners. Unfortunately, little is known on how to
control it, but here are two ways to minimize this effect:
Decreasing installation RPM speed will cause less friction and decrease heat generation. Lubrication
used prior to assembly can dramatically reduce or eliminate galling. Recommended lubricants should
contain higher amounts of molybdenum disulfide, such as graphite which is very commonly used as
a solid lubricant or special anti-galling lubricants sold by chemical companies.
We provide an anti-seize compound stick called “Thread Magic” (shown in picture below) with all of
our antennas and strongly encourage you to use it to reduce the aggravation of galling. The
Thread Magic stick is fantastic—you can get plenty of anti-seize on the fastener without getting it on
your hands!
Contrary to popular belief, galling of stainless steel is not a symptom of a "cheap" fastener - it is
prevalent in all types of stainless steel, aluminum and titanium fasteners. You can be assured that
the stainless steel fasteners we provide with our products are manufactured of very high quality.
A WORD ABOUT STAINLESS STEEL GALLING
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BOOM 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 increases 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 2) 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 assembling 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 2 shows joint # 1 markings inside the ring (they must line up).
Drawing 7 shows how each boom section is numbered.
Connect the boom by sliding the respective sections together and align the pre-drilled holes (Figure 3 and
4). Refer to Figure 6 and Drawing 7 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 excessive-
ly, 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 5). 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 with the
mast plate.
Figure 3
Figure 5
Figure 4
Figure 2
Figure 1
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