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SteppIR  Antennas - 4 Element 

29 

RF Power Transmission with the SteppIR Yagi

 

 
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 has proven to last over 2 million band changes.   The copper beryllium tape is .545 inches wide 
and presents a very low RF impedance.  The type of balun we are using can handle tremendous amounts 
of power for their size because there is almost no flux in the core and they are 99% efficient. That 
coupled with the fact that our antenna is always at a very low VSWR means the balun will handle much 
more than the 3

000 

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.   
 

WARNING:      WHEN OPERATING WITH MORE THAN 2

00

 WATTS, DO NOT TRANSMIT 

                            WHILE THE ANTENNA IS CHANGING BANDS.  A MISMATCH AT 
                            ELEVATED WATTAGES MAY CAUSE DAMAGE TO THE DRIVEN 
                            ELEMENT. 
 

Balun / Matching System

 

 
The SteppIR has a matching system that is included in all Yagi antennas (a balun is  available as an op-
tion on the dipole).  Our antenna designs are all close to 22 ohms at all frequencies, so we needed a 
broadband matching system that would transform 22 ohm to 50 ohm.  We found an excellent one de-
signed by Jerry Sevick, that is described in his book “Building and Using Baluns and Ununs”. 
 
Our matching network is a transmission line transformer that is wound on a 2.25 inch OD ferrite core 
that operates with very little internal flux (

Figure 40

), thus allowing it to function at very high power 

levels.  The transformer includes a 22 ohm to 50 ohm unun and a balun wound with custom made, high 
power, 25 ohm coax for superior balun operation.  Jerry has espoused these transformers for years as an 
overlooked but excellent way to match a Yagi, he would probably be proud to know they are being used 
in a commercial Yagi.  This matching network does not require compressing or stretching a coil, or sepa-
rating wires to get a good match – something that can easily be bumped out of adjustment by birds or in-
stallation crews. 

Balun 

Figure 40 

Summary of Contents for 4 Element Yagi

Page 1: ...4 Element Yagi Instruction Manual REV 3 0 September 2012 2112 116TH AVE NE SUITE 1 5 BELLEVUE WA 98004 WWW STEPPIR COM TEL 425 453 1910 FAX 425 462 4415 ...

Page 2: ...ontrol cable to the dSub splice 14 15 Attach the lid to the EHU s 16 Mounting the EHU s to the boom element brackets 17 Connecting the control cable to the terminal strips 18 20 Preparing the telescoping poles 21 Waterproofing the pole joints using polyolefin heat shrink 22 Attach the foam plugs to the telescoping pole tips 23 Secure the telescoping poles to the EHU s 24 25 Install the OPTIONAL 6m...

Page 3: ...2112 116TH AVE NE SUITE 1 5 BELLEVUE WA 98004 WWW STEPPIR COM TEL 425 453 1910 FAX 425 462 4415 SteppIR Antennas 4 Element 3 ...

Page 4: ...4 60 0050 3 8 NYLOCK NUT 4 60 0063 3 1 4 x 1 4 BOLT 50 60 0041 1 4 WASHER 4 60 0100 3 1 2 x 1 4 BOLT QTY PART NUMBER DESCRIPTION 1 60 0004 02 2 LONG U BOLT WITH SADDLE 2 60 0034 3 8 WASHER 26ft 21 8000 1200i PHILLYSTRAN 2 60 0083 4 SS TURNBUCKLE 3 60 0037 EYEBOLT 1 60 0085 4 THREADED BOLT 1 60 0042 2 FLAT PLATE 4 60 0044 PLASTIC END CAP 16 60 0045 3 16 WIRE CLIP 7 60 0046 5 16 NYLOCK NUT 4 60 0048...

Page 5: ...1 2 ELECTRICAL ENCLOSER 2 10 1029 01 CONNECTOR PROTECTOR bulb grease CP 1 2 20 6020 8 8 POSITION CONNECTOR 1 20 6020 1 1 POSITION CONNECTOR 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 Four of the below kits are used for the 4E Yagi ...

Page 6: ...SteppIR Antennas 4 Element 6 Abbreviations EST Element Support Tube EHU Element Housing Unit QD Quick Disconnect Boot rubber QD EHU EST ...

Page 7: ...ngth 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 avail...

Page 8: ... 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 su...

Page 9: ... required wiring Attaching the wiring enclosure and control cable to the boom Preparing the fiberglass telescoping pole Attaching the fiberglass telescoping pole to the element housing units Installing the optional 6M passive elements if ordered Installing the boom truss support assembly Build the Boom The boom Figure 1 5 is completely assembled and drilled at the factory to assure precision eleme...

Page 10: ...Driven Director 1 Director 2 2 2 3 3 4 4 5 5 6 6 1 1 Mast Foward NOT TO SCALE A B C D E F G 84 114 182 Drawing 1 Table 2 Bolt Sizes Required for Assembling Boom Joint Bolt Size QTY 1 1 4 20 x 3 w Nylok nut 1 1 5 16 x 4 Eyebolt nut 1 2 1 4 20 x 3 1 4 w Nylok nut 2 3 1 4 20 x 3 1 2 w Nylok nut 2 4 1 4 20 x 3 1 2 w Nylok nut 2 5 1 4 20 x 3 1 4 w Nylok nut 2 6 1 4 20 x 3 w Nylok nut 1 6 5 16 x 4 Eyebo...

Page 11: ... There is also a hole for a third 5 16 x 4 eyebolt used for the EZeye feature explained later located at the center point of the boom In stall this eyebolt with the nut and lock washer as shown in Figure 4 Now tighten the nuts on each bolt and eyebolt securely Before continuing to the next step verify that all nuts and bolts including those installed at the factory are securely tightened SteppIR A...

Page 12: ... sys tem Lift the boom so that the eyebolt in the middle rests on top of the EZeye threaded bolt Figure 8 This bolt can support the full weight of the antenna The mast plates in figures 7 10 have a different look than what you are actu ally given Note If you are doing this on the tower leave the safety rope or cable in place until you have secured the boom in place with the U bolts Place another 3...

Page 13: ...SteppIR Antennas 4 Element 13 ...

Page 14: ...SteppIR Antennas 4 Element 14 CONNECTING THE CONTROL CABLE TO THE D25 SPLICE ...

Page 15: ...SteppIR Antennas 4 Element 15 ...

Page 16: ...SteppIR Antennas 4 Element 16 ...

Page 17: ... washer needs to be placed BETWEEN each bolt head and the plastic ele ment housing to avoid damaging the housing when tightened Tighten the bolts securely but not too tight If you over tighten the nuts you may split the plastic flanges on the EHUs NOTE If the eight mounting holes for the element housing do not line up with the eight holes in the element bracket it may be necessary to loosen the tw...

Page 18: ...ing to the shack is connected Warning Do NOT connect the 16 conductor cable to the SteppIR controller until instructed to do so Carefully review Figures 17 and Drawing 4 before proceeding First complete the reflector direc tor and driven element wiring The 16 conductor cable wiring going to the controller will follow SteppIR Antennas 4 Element 18 Figure 17 Figure 16 16 Conductor Cable 4 Element to...

Page 19: ... end of the boom and tape all the cables snugly to the bottom of the boom so there are no loops or slack cables Six equally spaced tape points on each sides of the boom using two wraps of electrical tape each should be fine This is to prevent the cables from becoming damaged when mov ing the antenna and installing it on your tower Secure the 16 conductor cable and coax to the boom about 8 from the...

Page 20: ...ductor terminal strips as shown in Figure 17 5 Position the cables so they are parallel with the two 8 position terminal strips Figure 19 The single 16 conductor control cable will be on one side and the four 4 conductor cables the other Locate the unattached black ABS threaded plug and associated tube as shown in Figure 20 The ABS tubing serves as our wiring enclosure and protects the connections...

Page 21: ... 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 ...

Page 22: ...ioning the heat shrink place it so that the joint of the telescoping pole is centered in the middle of the heat shrink The pictures below exhibit how this is done Apply heat around the entire area of heat shrink Note There are 4 blue colored lines imprinted on the tubing The joint is considered done being heated and waterproof when the lines change color to a yellowish green Each line needs to cha...

Page 23: ...m plug and a flexible plastic housing for it as shown in Figure 1 The foam plug is sent to you already inside the black flexible housing 1 Insert the gray foam plug into the black flexible plastic housing Push the foam plug into the plastic housing until it bottoms out as shown in Figure 2 2 Push the black flexible plastic housing onto the tip of the pole Ap proximately 1 25 of the housing should ...

Page 24: ...ted at the factory prior to shipping but in the event the pole just won t fit it is okay to sand it to fit The EST s on the EHU s have aluminum reinforcing rings attached to provide extra strength in high wind conditions Figure 27 Locate the eight quick disconnect boots rubber and repeat the following procedure for each of the eight fi berglass telescoping poles 1 Remove the black rubber shipping ...

Page 25: ...wisting it There should be no slippage at the joints NOTE You should re tighten each clamp a second time at least 30 minutes after the first time be fore raising the antenna to the tower to be sure that there has been no cold flowing of the PVC material on the rubber boot Install the Optional 6 Meter Passive Element If ordered If you have purchased the optional 6M passive element kit Locate Ref Pi...

Page 26: ...YOU HAVE INSTALLED ONE SIDE OF THE TRUSS THE MEASUREMENTS FOR EACH SIDE ARE NOT EQUAL IN LENGTH Note Verify that the long element measures 110 5 and the short element measures 104 5 Securely fasten the pieces together with the 6 32x3 4 machine screws and Nylok nuts and install the U bolt on the center bracket as shown in Picture 32 5 The 6M passive elements should be mounted on the top side of the...

Page 27: ...s yet Position the eye of the turnbuckles on each leg of the U Bolt place the 2 flat plate behind them and fasten the 5 16 Nylok nuts securely as shown in Figure 36 When properly secured cut the remaining Phillystran cable for use on the other half of the truss Attach the thimbles Phillystran and wire clips in the same manner as in step one The finished assembly should look like Figure 38 While ho...

Page 28: ...To get maximum gain the boom of a three 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 11 dB If the boom is made shorter say 25 wavelengths the front to back can be as high as 25 dB but now the maximum gain is about 8 0 dBi Shorter booms also limit the bandwidth which is why right around ...

Page 29: ...ATCH AT ELEVATED WATTAGES MAY CAUSE DAMAGE TO THE DRIVEN ELEMENT Balun Matching System The SteppIR has a matching system that is included in all Yagi antennas a balun is available as an op tion on the dipole Our antenna designs are all close to 22 ohms at all frequencies so we needed a broadband matching system that would transform 22 ohm to 50 ohm We found an excellent one de signed by Jerry Sevi...

Page 30: ... degraded performance due to element interaction There are many antennas out in the world that are not getting the maximum theoretical gain from their boom Because we have tunable elements and a very efficient antenna we are getting close to the maximum gain from our boom Traps linear load ing and interlaced elements all contribute to this degradation Stacking Two Antennas Since SteppIR antennas a...

Page 31: ...SteppIR Options 40m 30m Dipole loop Y Cable Transceiver Interface cable Rig Specific 6m Passive Element Kit SteppIR Antennas 3 Element 34 SteppIR Antennas 4 Element 31 ...

Page 32: ... Voltage Suppressor RF Bypass Unit 16 Conductor Connector Junction Box Element Expansion Kit Dipole to 2 Element 2 Element to 3 Element 3 Element to 4 Element SteppIR Antennas 4 Element 32 ...

Page 33: ...SteppIR Antenna s responsibility is strictly limited to repair or replace ment of defective components at SteppIR Antennas discretion Step pIR Antennas will not be held responsible for any installation or re moval costs costs of any ancillary equipment damage or any other costs incurred as a result of the failure of our products In the event of a product failure a return authorization is required ...

Page 34: ...SteppIR Antennas 4 Element 34 ...

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Page 36: ...2112 116TH AVE NE SUITE 1 5 BELLEVUE WA 98004 WWW STEPPIR COM TEL 425 453 1910 FAX 425 462 4415 ...

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