First Tower Part 15 – Building Yagis (SteppIR DB36 Completed)

September 22, 2012 by AB1OC

Completed DB36 Yagi

We completed the assembly and testing of the first of our two SteppIR DB36 Yagi’s today. We installed the 80m dipole option on our antenna which provides a rotating dipole on 80m. This should work quite well at the 100+ ft height that our antenna will be installed at. The dipole runs parallel to the DB36’s boom and is attached to the element support trusses. The dipole uses the two end elements of the antenna as capacitance hats and a pair of loading coals to end-load the dipole. Its performance is just 0.8 dB below a full-size dipole on 80m. It also functions as a 60m dipole.

80m Dipole Loading

The 80m dipole attaches to an antenna switch which is mounted on the DB36’s boom support truss. This device enables the dipole to be switched in and out and matched to the feedline.

80m Dipole Switch

The single feedline to the antenna attaches to the switch and uses a pair of relays to connect the feedline to either the dipole or to the rest of the antenna depending upon which band is selected at the controller. The switch also contains a matching transformer and balun. A control cable runs from the switch to the main control cable connector box on the antenna. Note the knot in the control cable to keep it from being pulled out of the 80m dipole switch box.

Dipole Switch Internals

The final option to be installed on the antenna was the 6m Passive Element Kit. This kit adds two passive director elements to make provide a total of 6 elements on the 6m band. This improves the antenna’s gain and F/B ratio on 6m to 12.8 dBi and 27 dB respectively making it an effective 6m antenna.

6m Passive Element

The final assembly step was to complete the wiring of the main control cable and connect the controller to the antenna. Shown here is the main control cable connected to the Connector Junction Box on the antenna. The other end of the 24-pin shielded control cable connects to a DB25 Splice Connector which is attached to SteppIR’s SDA100 Controller. Note the two cable ties attached to the main control cable just inside the box. The cable ties act as a strain relief to prevent the heavy control cable from pulling on the associated connectors. It is important to carefully verify all wiring before connecting and powering up the DB36’s controller. We used DMM to verify continuity and proper connection of the control cable wiring. SteppIR also provides a document for troubleshooting which contains a series of resistance and short checks to do on each of the controller connections to the elements. It is important to do these resistance and short checks before you connect the controller for the first time as the miss wiring of the control cable can damage the controller if it is not corrected prior to power up.

DB36 Connector Box

After completing all of the resistance checks, we powered up the antenna and connected a feedline from the antenna to an antenna analyzer to check out the operation of the antenna on the ground. Before beginning the test, we enabled the 80m dipole and 6m passive element options in the controller. The next step is to run the calibration procedure on the antenna and then to individually run each of the elements out to its full length and check that each element motor is operating correctly and the associated element is fully extended. You can determine that an element is extended by gently shaking the element support tubes or sweep ends. If the element tape is extended, you will be able to hear it rattle inside the support tube.

With the elements checked out, we ran an SWR test on each band. The antenna is only 4 ft off the ground at this point so the minimum SWR reading on each band occurs about 500 – 700 kHz below the frequency settings on the controller which is normal. Also, the SWR measures higher than normal due to the antenna’s proximity to the ground.

DB36 Test Setup

What you are looking for is a pronounced “dip” in the SWR reading indicating that the antenna is Tuning to some sort of resonance. Shown below is the SWR measurement taken on 15m. In this case, the dip occurred at a frequency of about 300 kHz below the setting on the controller. All bands should be checked including 80m/60m (the dipole), the WARC bands (30m, 17m, and 12m) and 6m. It is also important that you switch between bands that are far apart and verify that the frequency of the SWR dip on a given band is consistent when the antenna is moved to a different band and back again. Any significant inconsistency between multiple readings on a given band indicates the unreliable operation of the antenna and needs to be investigated and corrected before the antenna goes on the tower. In our case, all of the tests and measurements checkout out fine.

DB36 Test SWR Measurement

The final step in the assembly of our DB36 was to attend to some details to ensure that the antenna is reliably on the tower. After carefully checking and making final adjustments on the boom and element support truss turnbuckles, we checked the tightness of the turnbuckle jam nuts and safety wired the turnbuckles to ensure that they will not come loose over time.

Safety Wire on Turnbuckles

We also added some additional coax seal where the control wires enter the element housings to ensure that this area is watertight. We did the same thing around the coax connectors on the Driven Element housing and the 80m dipole switch.

Control Cable Seal

It is also a good idea to check that all bolts are tight including the screws that hold the element housings to their support plates. I also checked that all of the electrical tape joints were smooth and tight. The final step was to remove the main control cable from the connector box and to tape a couple of cable ties and a packet of connector protector grease inside the connector box to make it easier to install the control cable and lock the box connector box lid closed once the antenna is on the tower.

The next step in our project will be to rig our 2m and 70cm Yagis on a test mast and test them prior to installation on the tower.

You can read more about our tower project via the articles which follow:

– Fred, AB1OC

First Tower Part 17 – Feedline Breakout System

September 21, 2012 by AB1OC

Feedline Breakout System

Since Anita (AB1QB) and I both want to operate at the same time, we are planning to put two SteppIR DB36 Yagis on our tower. These antennas will be connected to a DX Engineering Stack Matching System so that they can be operated together as a 4 over 4 array. The DXE Stack Match can select either antenna individually and connect it to the feedline associated with the array but it does not provide a breakout of both antennas onto separate feedlines. We designed and built a custom feedline breakout system to enable the simultaneous breakout of both antennas to separate feedlines. This project involved the construction of both a tower-mounted box to house a part of relays and a control box for the shack.

This device is inserted between the Stack Match and the antennas in line with the two phasing lines to each Yagi. It is critical that the breakout device provide identical impedance and phasing effects on both phasing lines if the array is to function correctly. To accomplish this, we selected a pair of Tohtsu Coaxial Relays (Model CX-800N) that have a very low SWR impact in the HF bands. These were installed in an outdoor utility box that we got from DX Engineering. Only one relay is used to break out the lower antenna to a separate feedline as the Stack Match can break out the upper antenna to the main feed line for the array. The reason that two relays are needed is to ensure that the RF performance of both phasing lines to the two antennas is identical.

Coaxial Relay

The relays require a 24V source to energize them. I built a simple control box for the shack to provide the needed control voltage. The controller includes three switches so that it can be used for additional 24V relay applications in the future.

Breakout Control Box

I wanted to be sure that the Breakout System had good isolation characteristics between the two phasing lines so that the device did not allow a transmitter using one antenna to interfere or possibly damage a transceiver using the other antenna. The relays we choose have good isolation characteristics which are a good start. To ensure that we have good isolation at a system level, I used an ArraySolutions Vector Network Analyzer (VNA) 2180 to measure the isolation between the various input and output connections in the Breakout System. The ArraySolutions VNA 2180 uses a PC and software to control a measurement unit that can perform one and two-port SWR, impedance, loss and phase measurements (many other measurements are possible as well). In this case, we are making a port to port loss measurement.

Isolation Measurement Setup using a VNA

The VNA 2180 has a dynamic range of about 100 dB which means that it can measure isolation up to this level. As you can see from the following screenshot taken with the VNA software, the isolation of the Breakout System is very close to the limits that the VNA can measure. The worst-case isolation measurement is about -97 dB on the 6m band. We also use Bandpass Filters when we are both operating and these filters provide an additional 55 dB or more of isolation which means we have a total of about 150 dB of isolation through this path. In the real world, the antennas themselves will likely have much less isolation between them than this so the isolation performance of the Breakout System should be more than adequate.

Isolation Measurement Results

We are making good progress towards the planned installation of three of our Yagis on the tower next week. I will provide some additional posts over the next several days covering additional aspects of the preparation for next week.

You can read more about our tower project via the articles which follow:

– Fred, AB1OC

Hardlines Have Begun To Arrive

September 18, 2012 by AB1OC

VHF/UHF Hardlines

The VHF/UHF hardline feeder cables arrived this week. We chose 1 1/4″ Hardline for the 2M antenna and 1 5/8″ Hardline for the 70cm antenna. Both of these Yagis will be at the 100+ ft level on the tower with a total feedline length of just over 200 ft. We chose these hardline sizes to keep the total loss in the feedline system to under 1.5 dB. We will also be using tower mounted preamplifier system to further improve the performance of the system for weak signal work.

Matt at XX Towers is planning to install three of our four antenna systems on the tower next week and we are preparing for this work this week. Here’s what remains to be done:

1) Test the first of the two SteppIR DB36’s
2) Build a custom feedline breakout system for the SteppIR DB36 Array
3) Change the hardware on the M2 Systems 2M18XX Yagi for a 3″ mast and test the antenna’s SWR performance
4) Add a boom support truss to the M2 Systems 432-21ATV Yagi
5) Gather all of the electronics, jumper coax cables, etc. and prepare for the installation

This is going to keep us very busy in the evenings and over the weekend.

– Fred (AB1OC)

First Tower Part 14 – Building Yagis (SteppIR DB36 Continued II)

September 16, 2012 by AB1OC

Driven Element Inner Support Tube

We began today by installing the remaining two-element housings on our SteppIR DB36. We first assembled and installed the element housing for Director 2. This step was nearly identical to what was done for the Reflector. The Driven Element housing is a different assembly due to its larger side. The first step was to install the two Inner Support Tubes onto the driven element stepper housing. These tubes are held in place with stainless steel clamps and a set of foam rings seal the inside of the driven element housing from the weather.

The next step was to support the driven element sweeps on sawhorses so that we could install them on the antenna. Note the white inner support tube extending out of the left element extension tube associated with the driven element. This is the end of the Inner Support Tube installed in the previous step.

Driven Element Loop

With the Driven Element sweeps installed, the final footprint of the antenna can be seen. The DB36 is truly a big antenna!

Completed Element Housings on DB36

The next step was to install the three Element Support Trusses for the elements with sweep housings (the Reflector, Driven Element and Director 2). You can see the support lines associated with the Reflector element support truss in the picture below. Similar truss assemblies were installed on the other two sweep elements and the support lines were adjusted so that the antenna elements droop about the same amount as Director 1. It is important that the ends of the sweeps droop enough to allow water which collects in the sweeps due to condensation to drain out of the ends for the sweeps. If they do not drain, the water can freeze and break the sweep housings.

Element Support Truss

The beginnings of the 80m Dipole assembly that will be installed on the upper of our two DB36 antennas are shown in the picture below. A support rope is fastened to the ends of the boom and to the element support truss posts to support the 80m Dipole.

80m Dipole Support End

The 80m Dipole switch is shown below. The 80m Dipole support lines from the ends of the boom are connected to the switch. The lines will support the wire for the 80m Dipole.

80m Dipole Switch

Well, our SteppIR DB36 is almost complete. Here’s a picture of the antenna with all of the element housings and associated trusses installed and adjusted.

DB36 with Element Truss Supports

We will complete the installation of the 80m Dipole, install the 6m Passive Kit, wire all of the control cables and test the antenna next. I hope to complete these steps sometime this week.

You can read more about our tower project via the articles which follow:

– Fred, AB1OC

First Tower Part 13 – Building Yagis (SteppIR DB36 Continued)

September 9, 2012 by AB1OC

Element Truss Support

A combination of the weather and a big work project has slowed our progress on the first of two SteppIR DB36s this week. We did make some pretty good progress this weekend. The first step was to install all of the remaining hardware which attached to the boom in preparation for attaching the control wiring to the boom. This involved installing three-element truss posts which will support the ends of the three large sweep elements. With this step done, I was able to tape the element control cables to their final position on the boom and loop the ends inside the control cable connector box for later wiring.

Connector Box and Element Control Cables

I also installed the 3″ mast clamp hardware to the mast plate.

Mast Clamps

The next step in the assembly of the DB36 was to prep all of the element poles. There are a total of 16 poles on this antenna – 4 each for the Reflector, Driven Element, and Director 2 and 2 for Director 1. Each of these poles had to be extended, cut to exact lengths and then sealed at the joints using the supplied heat shrink tubing pieces. We cut the poles using a power miter box and a fine 60 tooth blade. This worked very well. After chamfering the small ends of the tubes so that they would not catch the moving elements, we carefully cleaned all of the dust from inside the poles with an air hose. We also decided to spray each pole with two coats of Krylon 1305 UV resistant Clear finish. This required each pole to be sanded with 400 grit paper, cleaned and then sprayed.

Element Housing Poles Prepped for Assembly

The picture below shows the new heat shrink tubing installed on the poles. This system is much better than the older combination of silicon and electrical tape. All of the pole prep and finished took us an entire day.

Element Pole Joints

With the poles prepared for assembly, we assembled a pair of Element Sweeps Housings for the Reflector and installed the vents into the ends of the two Director 1 poles. We also glued together all of the pieces that make up the inner support tubes for each of the loop elements.

Element Sweep Assembly and Inner Support Tubes

With all of the element housing assembly completed, the final step was to install the housing for the Reflector and Director 1 Elements on the antenna. We moved the antenna a more open area in our back yard behind the tower to make room for the installation of the element housing. As you can see from the picture, the antenna is starting to take shape.

SteppIR DB36 with 2 of 4 Elements Housings Installed

SteppIR DB36 with 2 of 4 Element Housings Installed

My work schedule will preclude any further work on the antenna for about a week. I hope that the next post will show the first completed DB36!

You can read more about our tower project via the articles which follow:

– Fred, AB1OC

First Tower Part 12 – Building Yagis (SteppIR DB36)

September 5, 2012 by AB1OC

SteppIR DB36 Yagi (Courtesy SteppIR)

We have begun the assembly of the first of our two SteppIR DB36 Yagis. These antennas are large, complex machines that take some time to assembly properly and I plan to cover this part of our project in multiple posts. I will provide more pictures and details on this part of our project in hopes of helping others who might be building one of the SteppIR Dream Beam (DB) antennas. The DB36 covers all Amateur bands from 40m – 6m by using adjustable length elements which are controlled by Stepper motors. Each antenna includes a controller that sits in the shack and monitors the transceiver connected to it and continuously adjusts the elements for optimum performance as the transceiver is tuned. The following are the specifications for the SteppIR DB36 (Courtesy SteppIR):

Specification	DB36	DB36 with 80m Dipole Option
Boom Length	36 ft / 10.97 m	No change
Boom	1.75 – 2.5 in 4.45 – 6.35 cm	No change
Longest Element	49 ft / 14.9 m	No change
Turning Radius	26 ft / 8.0 m	No change
Weight	160 lb / 72.8 kg	164 lb / 74.39 kg
Available saddles for mast (2.0 in / 5.08 cm is standard)	1.75, 2.0, 2.25, 2.5, 3.0 inch 4.45, 5.08, 5.72, 6.35, 7.62 cm	No change
Wind Load	17.5 sq ft / 1.63 sq m	No change
Wind rating	100 MPH (EIA-222-C)	No change
Adjustable elements	4	No change
Power Rating	(40m-6m) 3 KW	(80m) 1.5 KW
Feed points	1	1
Frequency coverage	6.8 – 54 MHz	3.4 – 54 MHz
Tuning Rate	1.3 ft per second	No change
Control Cable	16 wire 22 AWG shielded	24 wire 22 AWG shielded

Performance for Ham Bands	DB36 Gain DBi	DB36 Front to Rear, DB
80M	1.35	n/a (pattern at right angle to elements)
40M	7.2	21
30M	8.2	18
20M	9.3	22
17M	9.9	27
15M	10.2	27
12M	10.4	21
10M	10.7	11
6M – 4 elements	4	2
6M – with optional passive element 50.0 – 53.3 MHz	12.8	27

The automated adjustment process allows the antenna to behave like a high-performance mono-band antenna at any given frequency which results in superior performance.

We elected quite a few options for our antennas so we had a number of different manuals to read and understand. The options included with our DB 36’s are:

80m dipole kit (add a rotating dipole on 80m – upper antenna only)
6m passive kit (improves gain and F/B performance on 6m)
Element truss kits (provides support for loop elements, improving the appearance of the antenna)
Connector Junction box (to make the correct connection of the elements to the main control cable easier and neater)
Transceiver interface, Tuning Relay, Advance Lightening Protection, 33V Power Supply Upgrade, and DB25 Splice Connector options for the Controller

The first step in the assembly of the antenna is to read all of the manuals, inventory all of the parts and assemble and organize all of the tools and components.

SteppIR is constantly updating its antennas to improve their reliability, ease of assembly and appearance as well as the antenna’s overall performance. An addendum to the manuals was provided which explained how to properly apply all of the revisions. As you can see from the picture, there are quite a few parts that make up one of these antennas.

Parts Inventory and Tools (First of two DB36’s)

The first step in the assembly process is to bolt together the sections that make up the 36 ft Boom. We made a set of 4 ft high sawbucks to support the antenna during assembly. Several sets of carpenter’s clamps were used to keep the boom fixed on the sawbucks.

SteppIR DB36 Boom

The next step is to carefully mark the location of all of the elements on the boom. Precise measurements are important here if the antenna is to provide the best possible performance. As you can see from the picture, there are quite a few measurements that need to be made.

Element Spacing on Boom (Courtesy SteppIR)

To make this job easier, we used cable ties to fasten a long tape measure to the boom so that we could mark all of the element mounting points accurately. We used a set of color pens to do this so the marks associated with each of the 6 elements were easy to identify. We used hose clamps to extend these marks to circles around the boom after marking all of the locations as shown below.

Element Layout on Boom

Each of the four adjustable elements uses a stepper motor housing that must be attached to the boom via a mounting plate and saddles. Three of the four elements are loops and these also require a return mounting assembly. As you can see from the diagram below, there is considerable hardware associated with each of the element assemblies. We took our time here to ensure that we did these steps properly. Most of the fasteners in the kit are stainless steel pieces and it’s important to use an anti-seize lubricant (supplied) on these fasteners to avoid galling when they are tightened. We also installed the control cables inside each of the stepper motor housings prior to mounting them on the boom.

Driven Element Assembly (Courtesy SteppIR)

It is important to get each of the element housings to be level on the boom so that the antenna elements are straight and parallel when assembled. To do this, we first fastened a level to the mast plate adjusting eye bolt and leveled the boom. With this done, we used a second level on each of the elements and return housings along the boom to ensure that all of the elements were level and parallel to each other.

Leveling Boom and Elements

This next picture shows the completed Driven Element Assembly after leveling and final tightening of the mounting saddles to SteppIR’s specifications using a torque wrench. Each saddle accepts a stainless steel set screw to lock one half of the saddle to the boom or the element extension tubes. These set screws are installed and tightened last, one in the accessible half of each saddle.

Installed Driven Element Assembly

We next installed the other three element assemblies (the Reflector, Director 1 and Director 2) on the boom leveling them as we went. Each element has a slightly different configuration so its important to carefully follow the instructions in the manual for each one. We marked each element’s control cable with a colored pen every foot or so. These colors matched the color-coding we choose for each element when we marked their locations on the boom – Red for the Driven Element, Blue for the Reflector, Green for Director 1 and Black for Director 2. This will make the wiring of the control cables easier and less error-prone at a later step. Also, if the wiring needs service once the antenna is on the tower, the color-coding is the only way to identify which control cable is associated with a given element.

Element Assemblies Installed on Boom

With all of the element assemblies completed, we next installed the mast plate, boom truss support tube, and the connector box option. The connector box option provides a neat way to correctly connect all of the elements control cables and the 80m dipole relay to the control cable down the tower to the controller in the shack. There is a threaded bolt/nut combination on the mast plate which allows easy leveling of the antenna once it’s installed on the mast.

Mast Plate and Connector Box

The next step was to install the Phillystran boom support cables and turnbuckles on the boom truss. The turnbuckles are adjusted to keep the boom straight and level.

Boom Truss

At this point, we have about three days of time invested in the assembly of our first DB36 yagi. The next step will be to assemble the element sweeps and support tubes. We will cover this and the additional steps needed to complete the assembly of the DB36 in a future post.

You can read more about our tower project via the articles which follow:

– Fred, AB1OC

First Tower Part 11 – Building Yagis (2m)

September 2, 2012 by AB1OC

M2 2M18XXX Yagi (Courtesy M2 Antenna Systems, Inc.)

This post is about the assembly of the second of our four Yagi Antennas – the M2 Antenna Systems 2M18XXX. This antenna uses 18 elements on 2m to provide approximate 17 dBi gain in a very tight pattern. It is designed for weak-signal and EME work on the 2M band. The specifications for the 2M18XXX are as follows (Courtesy M2 Antenna Systems, Inc.):

Model	2M18XXX
Freq. Range	144-146 MHz
Gain (single antenna)	17.14 dBi
Front/Back	26 dB Typical
Beam Width	E=26° by H=28°
Feed Type	“T” Match
Feed Imped.	50 Ohms Unbalanced
Max VSWR	1.2:1

Connector	“N” Female
Boom Length	36.5′
Max Element Length	41″
Turning Radius	19′ 6″
Stacking Dist.	14′ H, 14.5′ W
Mast Size	2″ Nom.
Wind area / Survival	2.9 SqFt. / 100 MPH
Weight	14 Lbs.
# of Elements	18

I began by doing a careful inventory of all of the parts for the antenna and gathering the necessary tools for assembly. Due to its size, I opted to assemble the 2M18XXX outdoors near the tower.

2m Yagi Parts

The first step was the assembly of the boom. I used the 2 foot high sawbucks that I made for the purposes of building our yagi antennas. A set of carpenter’s clamps were used to hold the boom in place on the bucks during assembly. The installation of the elements was next.

2m Yagi Boom and Elements

This step takes some time as each element has a different length and must be carefully centered on the boom. To make this easier, I marked the boom with a felt tip pen to indicate the location of each element for easy cross-reference with the dimension sheet from M2 Antenna Systems.

2m Yagi Element Layout (Courtesy M2 Antenna Systems, Inc.)

Next came the assembly of the driven element and associated balun. The location of the shorting bars on the Driven Element Assembly is important in order to get a proper match between the feedline and the antenna.

2m Yagi Driven Element

The 2M18XXX has a long boom (36 1/2 ft.) and requires a Truss Support. The picture below shows the boom truss support system after it is assembled. The standard mast plate and hardware supplied with this antenna by M2 Antenna Systems will accommodate up to a 2″ mast. We will be using a 3″ mast so M2 supplied a custom mast plate and a Truss Support that clamps directly to our 3″ mast. To make the antenna easier to test, I first assembled it with the 2″ hardware so that I could test it without attaching it to the mast.

2m Yagi Boom Support Truss

Here is a picture of the completed 2M18XXX. It is a very well-built antenna and it should perform well once it is installed at the 110 ft + level on our tower.

Completed 2m Yagi

I am going to move onto the construction of the first of our SteppIR DB36 antennas next. I will provide a post covering this step of our project next.

You can read more about our tower project via the articles which follow:

– Fred, AB1OC

First Tower Part 10 – Building Yagis (70 cm)

August 30, 2012 by AB1OC

M2 440-21 ATV Yagi (Courtesy M2 Antenna Systems Website)

I decided to build the simplest of our four Yagi antenna first – the M2 Antenna Systems 440-21 ATV. This antenna features 21 elements on a 14 1/2 foot Boom and provides excellent gain and F/B performance. Here are the specifications for the M2 440-21 ATV Yagi (Courtesy M2 Antenna Systems Website):

Model	440-21ATV
Frequency Range	420 To 440 MHz
Gain	18.04 dBi
Front to Back	23 dB Typical
Beam Width	E=22° H=24°
Feed Type	Folded Dipole
Feed Impedance	50 Ohms Unbalanced
Max VSWR	1.2:1 Typical

Input Connector	“N“ Female
Boom Length / Dia	14’ 6“’ / 1“
Max Element Len/Dia	13-7/8“
Turning Radius	96“
Stacking Distance	65“ High & 65“ Wide
Mast Size	2“ Nom.
Wind area/Survival	0.85 Sq.Ft. / 100 MPH
Weight / Ship Wt	5 Lbs. / 6 Lbs.
# of Elements	21

Our mast is a 3″ piece so M2 made up a custom mast plate for us (more on this in a bit). The first step in the assembly of the antenna was to layout and inventory all of the parts and to thoroughly review the assembly instructions.

70 cm Yagi Parts

The next step was to assemble the boom and to install the 21 elements using the supplied insulated bushings and lock rings. The element installation takes quite a bit of time as most of the elements are of different lengths and they must be properly centered on the boom. To make this process a little easier, I used a marking pen to number each element location on the boom so that I could easily determine which length element went in each location on the boom.

70cm Yagi Boom and Elements

The next step was the installation of the driven element, balun, and associated matching system. The key to this step is to install the coupling bars at the proper location on the driven element/matching unit.

70cm Yagi Driven Element

The final step in the assembly of the antenna was to install the mast clamp. We are using a 3″ mast on our tower and M2 Systems made a custom mast clamp plate to accommodate our mast. The mast clamp should be placed on the boom at the point where the boom including the weight of the feedline balances the antenna relative to the mast. It’s important to get the mast plate installed so that the elements of the antenna are at a right angle to mast. This is easily done by leveling the elements of the antenna in the vertical plane and then using a horizontal level to get the mast plate perfectly square with the antenna elements.

70cm Yagi Mast Clamp Installation

These steps complete the antenna assembly. The only step that remains is to test the antenna and rig it with a coax jumper cable before it does on the tower.

Completed 70cm Yagi

One can do a reasonable test of a Yagi of this type by elevating it 10 – 15 ft and doing an SWR test. I attached a 20 ft length of LMR400 UltraFlex feedline to the antenna, carefully fastening it to the boom of the antenna so that it did not couple to and interact with the antenna. I then used a RigExpert AA-520 Antenna Analyzer to verify that the Yagi’s SWR was as expected.

70cm Yagi Test

At this point, the first of the four Yagi antennas is complete and I plan to tackle the 2m Yagi next.

You can read more about our tower project via the articles which follow:

– Fred, AB1OC

Antennas Arrive!

August 23, 2012 by AB1OC

Yagi’s Delivered

All four of our Yagi antennas arrived today! Two VHF/UHF Antennas from M2 Systems and our two SteppIR DB36 Antennas for HF/6m. Now the fun begins. The plan will be to assemble the 70 cm beam first. I will post pictures as we go.

– Fred (AB1OC)

First Tower Part 9 – Feedline Conduits And Electrical Power Complete

August 16, 2012 by AB1OC

Conduits & Electrical at Tower

We made some more progress on our tower project today. Brian Veillette (Nashyei@aol.com), our excavation contractor, completed the conduits for our feedlines today and Brian Fessenden (fessendenbrian@yahoo.com), our Electrician, added an electrical outlet at the tower to provide power for our rotating ring and for general use at the base of the tower. We installed one 6″, one 4″ and two 2″ conduits to accommodate all of our hardline feed lines and control cables. These will allow us to run all of the cabling underground from the tower to our shack entry.

Conduits at Shack Entry

It will take a little time for our lawn to “heal” but it’s nice to have these steps completed. It looks like some of our four yagis may arrive as early as late next week and the next major step will be to assemble them.

You can read more about our tower project via the articles which follow:

– Fred, AB1OC

Our HAM Station

Notes on the construction and operation of a multi-op Amateur Radio Station

Tag Archives: Antennas and Feedlines

First Tower Part 15 – Building Yagis (SteppIR DB36 Completed)

First Tower Part 17 – Feedline Breakout System

Hardlines Have Begun To Arrive

First Tower Part 14 – Building Yagis (SteppIR DB36 Continued II)

First Tower Part 13 – Building Yagis (SteppIR DB36 Continued)

First Tower Part 12 – Building Yagis (SteppIR DB36)

First Tower Part 11 – Building Yagis (2m)

First Tower Part 10 – Building Yagis (70 cm)

Antennas Arrive!

First Tower Part 9 – Feedline Conduits And Electrical Power Complete

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