Category Archives: Antennas

Articles about Antennas, Feedlines, Towers and related equipment. Fixed, Portable and Mobile Antenna Articles are included.

I Can’t Believe My Antenna’s Up!

I suppose the title could also be: (or how I learned to stop procrastinating and finally put up my HF antenna).

Well, I did it. I finally got my HF antenna up after months of admiring it through the plastic wrap and having the world’s most expensive paperweight (IC-7300) sitting in my metashack (how could I really ascribe any reality to it when it was still merely a concept). What I would like to accomplish in this article is not only a description of the construction etc. but also of some mental gymnastics, I had to do in order to get to the finish line.

Way back in February, I was able to get my General license. I was pretty stoked (to use the common tongue) and looking forward to getting it up and going. This required, essentially, two things: a radio and an antenna. Easy-peasy, right? The first really was easy. I wanted a 7300. Who didn’t? The proverbial ICOM bandwagon drove by my house daily. Several times a day while banging on a few drums. So, I did my homework as best as I could, talked to a few folks, and with not much arm twisting, bought a rig. Now I needed the antenna. And some drums…

For this portion of the ordeal, I ended up doing my homework a little more. I spoke to Fred and Anita at length about their choices: read their blog, saw their own setup in person, read posts in the Elmering session of Nashua ARC’s website, read comments on eHam.net about various antenna types. Some factors to consider are — in no particular order:

    1. Budget
    2. How much help you will have to put this up
    3. Aesthetics
    4. Available real estate
    5. How many bands do you want to work

At my QTH in MA, I have 0.5 acres in the front and back.

My QTH in Tewksbury, MA
My QTH in Tewksbury, MA

Having done my homework, I decided to go with the Buckmaster 7-band off-center fed dipole rated for 3 kW.

First Antenna - 3 kW antenna at the top
3 kW antenna at the top

I think the price point was a bit north of 300 bucks. Having made up my mind, I didn’t do anything about it. Upon reflection, I think I really didn’t act because work consumed me until mid-May. I literally had no free weekends for months, so there was no rush. In the interim, Fred and Anita had opened up their station for use, and I took joy in hearing about others’ QSOs for a while.

In order to still feel like a HAM, however, I decided to take my Extra exam in May. Once I that got out of the way I bought the Buckmaster in June on one fateful Thursday afternoon, and again, there it sat in the meta shack until September. Excuse #2: Honestly, with a project this big (at least for me) I think I was a bit gun-shy to get it up. I felt unqualified to do it; maybe even afraid to fail amidst all these competent people in the club.

Up until now, this may have read as Dear Diary, so let’s get to some actual station construction! Labor Day weekend was the ticket.

Good grief was this tough! Probably 85-90% of the total time was spent trying to figure this out. Mainly because, looking at the graphic, I had to get this about 35 ft. in the air. I got frustrated pretty quickly…

Buckmaster OCF dipole installation picture. Right from their website
Buckmaster OCF dipole installation picture. Right from their website

Now maybe that doesn’t seem like it’s that high, but I assure you, it becomes pretty darn high when you keep failing. So thinking about the problem and researching on the internet led me to some methods to try to get a rope up in the tree:

  1. Use a potato gun
  2. Call folks from the club to come lend a hand
  3. Rent a scissor lift from Home Depot
  4. Use a bow and arrow
  5. Use rope tied to a rock or stick and try to launch over the branch I want.

Here was what the jury decided on each of these options:

  1. Built one! Fires really well, but had issues initially with sparking it in the combustion chamber. Turns out the reason was due to insufficient amounts of butane getting into the chamber. In any case, I abandoned this as a choice. But who’s to say I can’t be mischievous at a later date.
  2. I felt bad bothering folks despite one ethos of amateur radio is to Elmer each other, so I didn’t ask for help. Bad news bears to those of you in the same predicament.
  3. Too expensive for the little time I needed it. I think Home Depot (spelling error intentional) wanted something in the neighborhood of 200 bucks or more.
  4. Don’t have one and nearest friend with one lived in Carlisle. Would have to work around his schedule and at this point, I was thru being patient.
  5. Rock idea worked reasonably well, but honestly, the best option was to get a stick and tie nylon fishing line around it. I have a pretty good arm it turns out, so I tied fishing line around the stick and started throwing.

In full disclosure, the elimination of these options takes us from Friday to Monday. Wisps of steam could be seen emanating from my ears.

The stick was attaining the requisite height and hitting where I needed it to. The huge snag (no pun intended), though, was the fishing line was getting caught in the branches on the way down. Yet another problem. Cue engineer father-in-law. He’s the guy labeled “this guy” in the picture.

Helper Dude
Helper Dude

He recommended winding a large amount of fishing line around the stick (but not all of it so that there would still be some left over on my side of the branch) so that when it came down the other side of the branch, it would unravel and not be as likely to get caught. This worked like a charm!

With the fishing line on either side of the branch, we tied the actual nylon, water / UV resistant rope (which I picked up at Home Depot) somewhere 25% up my side of the fishing line and then got on the far side of the branch and began hoisting it up. This also worked out very well.

First Antenna - Same father-in-law and hanging ropes which will support the Buckmaster
Same father-in-law and hanging ropes which will support the Buckmaster

Finally, with the rope I actually want to use over the tree, I tied the Buckmaster to one end of the rope on my side of the branch and then raised it up. I lowered and raised it a few times to make sure it wouldn’t get caught in the tree at any place. I tied off the free end through an eye screw that I screwed into the tree.

The coax I used was LMR-400. Again, doing my homework, I decided to splurge and buy 200 ft of coax but without the PL-259 connectors. I did this because I wanted to be able to cut the coax where I wished and would subsequently learn how to attach the connectors myself. This too turned out to be a relatively easy job. I picked up some connectors at the Boxboro Hamvention and borrows Dave’s (N1RF) crimper set (with dies) to attach the connectors. Taking my time, I was able to do both ends of the 200 ft coax in about 30 minutes tops. I also purchased some Super 88 electrical tape from Home Depot as well as used Scotch’s 2228 Moisture Sealing Electrical Tape (some other folks use CoaxWrap) for weatherproofing. I applied this following Fred’s suggestion on his blog.

First Antenna - Layers of super 88 and weatherproofing electrical tape fastened to antenna connection point
Layers of super 88 and weatherproofing electrical tape fastened to antenna connection point

With the feed-point setup, I then purchased two more nylon, water/UV resistant ropes to connect to the Buckmaster’s insulators. I found that the 3/16” diameter by 100 ft. rope worked well (3/16″ fit nicely through the insulators’ 1/2″ holes), again purchased at Home Depot. Shirley, the cashier, shot me a smile after ringing me up for the umpteenth time. To temporarily tie these off, I terminated the rope through some more eye screws I screwed into trees in my yard. But for the final installation, I will again follow Fred’s advice from his blog post.

Then, I ran inside, ran the coax through the window thereby performing the transformation of the meta shack into a proto shack! (Proto because it’s in the process of getting changed and upgraded) Ta da! Prestidigitation! That night I worked Brazil and the Czech Republic on 20 and 40 m respectively, and Australia around 0615 the next morning on 20m.

Protoshack, Coax not shown.
Protoshack. Coax not shown.

My follow up projects:

  1. I never mentioned grounding. I do have an 8 ft copper ground rod that I will install. I bought lightening arresters from DX Engineering: I have the kind that allows the passage of DC voltage which is needed for utilizing an antenna switch down the road. Since I plan on buying an antenna switch later, this seemed like a good option. This entire installation will take some time, so I need to find a free weekend. For now, I am only operating when the skies look perfect!
  2. Install my 15 m dipole that I bought from the HRO and covers the band not covered but the Buckmaster. This will likely happen in the Spring. For reals.
  3. Track down RF interference sources in my home and install the necessary chokes and beads. I’m kind of looking forward to this step.
  4. Find a final resting height for the radiating wires of my Buckmaster. I have a cousin with tree climbing equipment. Once he comes over to trim some branches etc., I am going to try and make a 180-degree angle with the wires as best as I can. Additionally, my wife wants me to switch out the white, nylon, water/UV resistant rope with dark colored rope since it’s a bit too visible.

Once I got going, I really had a blast. If I can be of any help to anyone about this, please feel free to send me a reply or contact me on the club website. Thanks a lot for following me through the whirlwinds that are my thoughts, and see you on the air!

Best and 73,

Brian (AB1ZO)

Hands-On Yagi Antenna Construction 2.0 for Teaching and Experimentation

The most important piece of equipment in ham radio is our antenna.  We are connected to the world with the magic of radio waves!  Each License Exam from Technician through Extra class has questions to test our knowledge on antenna design and building skills.  Home-brewed antennas are easy and relatively inexpensive projects.

This article describes a 2m, 3-element Yagi antenna construction concept that the N1FD FCC license teaching team has used over the last year for class demonstrations.  The “Lego” style construction (v. 2.0) shown in the above picture is our new design that demonstrates the operating principles of the ubiquitous basic dipole antenna as well as a 2-meter, 3 element Yagi.  (Note, This project evolved from an earlier effort by Diana Eng at Makezine.com, which can be seen here.

In this Newsletter issue, we will describe the construction of the “Lego” stylized antenna and show how it can illustrate basic properties of a dipole antenna.  We will build a Yagi antenna with the addition of reflector and director arms in a future Newsletter article.

CONSTRUCTION of the LEGO STYLIZED ANTENNA.

Yagi Antenna - Lego Antenna Parts and Receiver Antenna
Lego Antenna Parts and Receiver Antenna

The antenna demonstration unit consists of two assemblies. 

  1. A handheld receiver dipole set to a fixed frequency (e.g., 146.550 MHz). It is shown at the top of the photo above. It follows a “plumber’s delight” construction using pieces of PVC pipe for a short boom and handles.  The dipole arms are two telescoping (7-28 inch) FM radio replacement antennas, available on eBay or Radio Shack ($4-6 dollars).  The arms feed through the boom and are epoxied.  Bridging across the arms is a common 6-volt flashlight bulb.  The bulb lights up when the dipole receives a resonant rf signal.
  1. The “Lego stylized” Yagi antenna components are shown below the receiver unit. The boom (middle item) is made of red oak dimensioned at ¾  x  1 ½   x  48    The top surface is grooved to hold an epoxied  3/16  steel rod.  The bottom surface has drilled recesses to fit ¾ in PVC pipe for leg stands. The edge of the boom has two 24-inch adhesive tape rulers running from center to front and back of the boom.  The rulers read-out the spacing between the driven dipole element and the parasitic reflector and director arms. In the photo, the D.E. and parasitic elements are seen below the 48 in. boom.  The center element is the driven dipole and it is flanked by identical units that can be configured as either reflectors or directors.   Each unit consists of two telescoping FM radio antenna rods epoxied in a grooved piece of red oak ( ¾  x  1 ½  x  3 inches) serving as “riders” on the boom.  The telescope arms can be adjusted to “resonance” at any frequency in the 2-meter band. The bottom of all riders has 2 x ½ inch rare earth magnets.  These allow the three antenna elements to be fixed at any position on the 48 in. boom.

You can view a closer look at the assembled Yagi antenna configuration in this video (Click on Link)

DEMONSTRATIONS OF BASIC DIPOLE BEHAVIOR. 

1.  Antenna Resonance Determined by Dipole Length.

As we all know, the resonance length of a dipole is given by the equation:    L (in inches)  =  5616/ [ Frequency (in MHz)].  We can show this fact with aid of the “receiver” antenna, which is set for a frequency of 146.55 MHz  The light bulb of this antenna will light when it senses a signal of this value from our “Lego” antenna.

In the video below (Click on Link), we begin with a resonant D.E. length of 38.5 inches and see the receiver antenna light up.  Next, we manually shorten the D.E. and see the bulb light dramatically dim.  When the D.E. length is returned near the start value, the light bulb again brightens up.

  1. Effect of SWR on Signal Strength.

Most modern transceivers have a built-in auto-tuner that can match SWR up to 3:1.  We know this only makes the “radio happy”, still we key down without much thought on how our Tx signal degrades with a 3:1 match.  The pictures below use the transmitting “Lego” dipole and receiver dipole to show the received signals for an SWR of 1.1 and 3.0.  The SWR was changed by lengthening the D.E. elements by 2 inches while holding the Tx frequency at 146.55 MHz

Yagi Antenna - Receiver Signal-for Lego Dipole SWR 1.1
Receiver Signal-for Lego Dipole SWR 1.1
Yagi Antenna - Receiver Signal- for Lego Dipole SWR 3.0
Receiver Signal- for Lego Dipole SWR 3.0
3.  Polarization Effects between Tx and Rx Antennas.

A horizontal dipole shows “horizontal” polarization; meaning the electric field vector of the rf signal is parallel to the earth surface.  Similarly, a vertical dipole displays “vertical” polarization with the electric field perpendicular to the earth. We all learn this in a Technician class course.

When we use our 2m HT’s for short distance contacts, Tx and Rx antennas with opposite orientation create a huge signal loss.  The effect is shown dramatically in the video below.

CONCLUSION 

Our classroom constructible antenna for demonstrations in our Ham Radio license classes has evolved in design over the past year.  We believe it has been a useful resource,  helping students translate textbook theory to “Hands On” practice.  Perhaps, this review has kindled interest for our readers to think of their Next Antenna Project!

73 & Hope to hear you on the air,

Dave N1RF

Summertime Station and Antenna Projects At AB1OC/AB1QB

Summer is the time of year that many of us work on our antennas and improve our stations. Anita AB1QB and I did both of these things at our QTH this summer.

Antenna Projects - Removing Lower SteppIR Yagi From Tower
Removing Lower SteppIR Yagi From Tower

Our SteppIR DB36 Yagis were due for some maintenance so we took them off our tower. Special thanks to all the members of the Nashua Area Radio Club who helped us remove, recondition and reinstall our antennas! Matt Strelow, KC1XX of XX Towers and Andrew Toth provided equipment and know how to safely remove our two large SteppIR DB36 Yagis with help from the rest of us.

Antenna Projects - Lowering Antenna With Electric Winch
Lowering Antenna With Electric Winch

The SteppIR DB36 Yagis weigh almost 200 lbs each and Matt made good use of his electric winch to lower them.

Antenna Projects - Antenna Coming Down The Tram Line
Antenna Coming Down The Tram Line

The picture above shows the lower antenna coming off the tower. We used a Tram Line system to lower both antennas to the ground so that we could rebuild them.

Antenna Projects - SteppIR DB36 Antenna On The Ground
SteppIR DB36 Antenna On The Ground

The SteppIR DB36 Yagis are quite large. They have 36 ft booms and the driven elements are almost 50 ft from tip to tip! They completely fill up our back yard when they are both off of the tower.

SteppIR Rebuild

Antenna Projects - Element Pole Sun Damage
Element Pole Sun Damage

The rebuild process began with a careful inspection of both antennas. They were both in good overall condition with some sun damage to the paint on the fiberglass element poles.

Antenna Projects - Disassembled SteppIR DB36
Disassembled SteppIR DB36

We removed all the element tubes and sweeps from both antennas for rebuilding. The picture above shows the disassembled upper antenna.

Antenna Projects - Rebuilt Stepper Motors Installed
Rebuilt Stepper Motors Installed

All four Stepper motors on both antennas were replaced. These motors move metal tapes inside hollow element tubes to adjust the length of each antenna’s 4 movable elements. These adjustments are done automatically by controllers in our shack which receive frequency information from the radios which are connected to each antenna.

Antenna Projects - Reconditioned Element Sweep Poles
Reconditioned Element Sweep Poles

All of the element housing poles were cleaned, prepped and painted with a UV resistant clear coat to protect them from further sun damage. The poles cleaned up like new.

Antenna Projects - New Element Sweeps Ready For Installation
New Element Sweeps Ready For Installation

The assembly of all the new element sweep tubes (shown above) was done next. Each antenna has six sweeps.

Antenna Projects - Element Pole Preparation
Element Pole Preparation

The end of each element pole must be prepped with a tape system which ensures that the poles are seated properly, sealed to and firmly attached to the sweeps. This process and the associated assembly and tightening of the element couplers was the most time-consuming step in the rebuilding process as it had to be repeated a total of 24 times.

Antenna Projects - Rebuilt Element Assembly
Rebuilt Element Assembly

Here’s a picture of one of the rebuilt element tube assemblies. The ropes support the element tubes and keep them aligned when the antenna is up in the air. These elements are attached to the antenna motors with couplers and clamps.

Antenna Projects - SteppIR DB36 Yagi Rebuild Complete
SteppIR DB36 Yagi Rebuild Complete

The picture above shows the lower antenna with all the element tubes reattached. There is quite a bit of additional prep work associated with adjusting all the supports and taping all the exposed areas of the antennas which are susceptible to sun damage. Also, all the electrical wiring on the antenna must be checked to ensure good electrical connections and good overall condition of the wiring.

SteppIR Ground Testing

 

Antenna Projects - Ground Test Setup
Ground Test Setup

The final step in rebuilding the antennas is to test their operation on the ground. This ground test is done to ensure that all the motors are working correctly and that the element tapes move smoothly inside the rebuilt element tubes.

Antenna Projects - Ground Test Results
Ground Test Results

Another important part of the antenna Ground Test is to confirm that the antennas have a consistent resonant frequency and SWR on all bands. The resonant frequencies and SWR levels are far from those that would be measured when the antennas are on the tower at operating height. The idea here is to confirm that a resonance exists and that its frequency and SWR readings are repeatable as the antenna is adjusted to different bands.

SteppIR Installation and Final Testing

 

Tramming Antennas Onto A 100 Ft Tower

With both antennas rebuilt, its was time for Matt and Andrew to return and, with help from folks from our club, reinstall the rebuilt antennas on our tower. The video above shows this process. It is quite something to see! The installation took about 3 1/2 hours.

Antenna Projects - Updated SteppIR Controllers
Updated SteppIR Controllers

The last step in the SteppIR DB36 rebuild process was to install the latest firmware in the associated SDA100 Antenna Controllers. There were some integration issues between the updated SteppIR Firmware and our microHAM system but we are getting those worked out with help from the folks at both SteppIR and microHAM.

Transceiver Upgrade

 

Icom IC-7851 With Display Monitor
Icom IC-7851 With Display Monitor

I recently had a major birthday milestone and Anita surprised me with a new radio – an Icom IC-7851. This radio is an upgrade/replacement for our Icom IC-7800. While the two radios are quite similar in their operation and interfaces, I did not want to install the IC-7851 until the SteppIR antennas were reinstalled and all of their upgrades were working properly with our current radios. With the antennas done, it was the time to install the new radio!

Icom C-7851 Transceiver
Icom C-7851 Transceiver

The Icom IC-7851 has several important performance upgrades. The most impactful one is a new low phase noise oscillator which significantly improves RMDR performance compared to the IC-7800. The IC-7851 is in the top-tier of Transceivers in Sherwood Engineering’s tests. The receivers in the IC-7851 are very quiet, have excellent Dynamic Range and perform great in when close-in interference is present.

Icom IC-7851 Display Monitor
Icom IC-7851 Display Monitor

The Icom IC-7851 has a higher resolution and faster display. It also supports higher resolution external monitors so we installed an upgraded display monitor along with the new radio. The IC-7851 has a number of new networking features and supports stand-alone remote operation over a LAN and the Internet. We are planning to use these capabilities to add a second remote operating gateway to our station. More on this in a future article.

The combination of the rebuilt antennas and the new IC-7851 Transceiver has our station performing better than ever. The antennas are working as well or better than when they were new and the IC-7851 has significantly better receive performance compared to its predecessor and is a pleasure to use.

We will be hosting the ARRL Rookie Roundup RTTY contest for our club members who have received their first license in the last 3 years next weekend and we’re going to use the new radio and rebuilt antennas for the contest.

This project was completed in a little over two weeks and was a lot of work. I could not have done the project without the help of the many folks in our club. Again, a big Thank You to all the folks in our club who helped me with this project! I hope that many of you will be able to find some time to operate from our upgraded station.

73,

Fred, AB1OC

Radio Amateurs Developing Skills Worldwide