A Homebrew Magic Band Beam (With an Update)
So here I am again. Still young in the amateur radio field. I made that microphone switch and that worked wonderfully. So I decided I’d try my hand at a beam antenna.
I’m not sure what spurred my desire for a 6 meter beam, other than size, maybe. I think my first bits of material didn’t amount to enough to make a 10 meter beam, so a 6 meter would have to suffice.
The start of this project involved deciding where to get my materials. I researched all over the internet and didn’t like the cost of either a complete 6 meter beam, nor the cost of materials to make one. I mulled over materials I may have laying around and found an old deep fringe television antenna, long forgotten in the weed near the fence in the back yard.
I went out to the old fence line and sure enough, there was that old antenna. It didn’t look promising at first. I carefully coaxed the old antenna from the grip of the weeds. The force was strong with them. I finally got out the main beam of the antenna with a few elements still attached. Some were firmly attached while others were broken or seriously bent.
I took what I could and began to cut and drill the old antenna apart.
It really didn’t take too long to drill off all the old plastic parts. I was left with a couple of bare beams with which to begin the process of building my 6 meter beam.
The next process, which I don’t have a photo of, was simply selecting the best, longest, straightest elements to reuse. That selection was pretty thin and short.
Next I discovered a beam calculator online. This one is from http://www.csgnetwork.com/antennae3ycalc.html — I chose 50.1 for the frequency to provide close access to 50.125.
There I had my dimensions. I used those to calculate the total length of the beam that I would need to make this. I simply used the brackets from the old antenna to splice two beams together.
After having a beam of sufficient length, I moved on to the mounts to isolate the elements from the beam. I thought about using wood, but figured it wouldn’t last particularly long in the weather. I tossed around other ideas and came to settle on one of those plastic cutting boards. So I went to our local discount store and bought two small plastic cutting boards. Well under $5.00 for both. I used my table saw to cut up those boards into pieces about 7.5 by 1.5 inches. After that, I measured the center of the newly created beam and located where each of the elements would land. I used hex washer head self-drilling screws to mount the cutting board pieces.
I cut out a radius from the center one which would be the driven element and mounted a panel mount SO239 to the underside of the cutting board.
You can see the flattened and soldered frayed end of the wire. I drilled a hole through that and used the mounting screw to attach one side of the driven element to the SO239.
On the top side, I made another short piece of wire and soldered that to the center post of the SO239. The other end of both wires were shaped into a loop, just big enough to wrap around the self-drilling screws and soldered to hold that shape. After they were attached to the SO239, I covered the entire feed point in hot glue. I made sure to spread the glue out away from the connector to avoid water standing on it.
Next, it was on to the elements. That was fun.
Since I didn’t have any elements close to the right length, I needed to figure a way to splice them. The method I came up with was fairly straightforward, if not slightly challenging.
I cut shorter pieces with mangled ends, on both ends. Then I took the elements that were still viable with factory ends and using regular channel lock pliers, I began to crimp one side of the element where they were originally “cut.”
I did this for several inches to assure proper length when finished. When all said and done, I had one piece with its original diameter and one with a reduced diameter.
You might notice that crimped tube isn’t straight. That’s no problem. Even in that condition, I put them together, with a lot of convincing.
Once I was sure of the total length of the element, I placed 2 zip ties, pulled as tight as they would allow, to crimp the two pieces of element together. Once they were together, I simply bent them straight.
Now that I had all of my elements. I simply used those same self-drilling screws to affix the elements to the cutting board pieces. On the driven elements, I used that looped wire under the screw on top of the element on each side. Two screws hold on each element. I made sure to space the screws far enough from each other that there would be no continuity between the beam and elements. You can see the screws protruding on the feed point photo above.
Once all the elements were attached, it was testing time.
I mounted it on a board on a vertical 2×4 that was clamped to my trailer. Yes, a little bit of redneck engineering. It tuned, but the band was dead.
Still, I was fairly confident it would work, so I mounted it up above my television antenna pointing in the opposite direction. (I’m not sure why.)
Once it was up there, I was very pleased that it would tune from 50.000 to 54.000 at a 1:1 SWR. Now for the waiting game.
Months passed without hearing a soul on the calling frequency of 50.125. So, I began calling CQ. Months more passed without hearing any other signal. I was beginning to think my antenna didn’t work.
But one day, one day, that one magical day…I heard my call come back. It was faint and it was noisy, but there was no doubt it was someone returning my call. I rotated the antenna around to see if I could get a stronger signal. Barely, but yes. I heard his call…WA9ASZ. WooHoo! My antenna worked. That was a tough QSO, but one where he and I exchanged enough, I heard him say “I’ve got you in the log”.
Needless to say, I was ecstatic. Not only a QSO on my homemade beam, but one for the “Magic Band”. It was nearly immediately after I lost Steve when I heard a booming signal. I had to spin the beam around and picked up KY4SGM. TWO contacts!! I was already hooked.
Several more weeks had passed with no other voices heard on 6 meters. I played around on CW, which I’m just learning, and made a couple of contacts on there.
Then the weather decided to have some fun. There were a number of particularly windy days. One day I clocked 41.2 mph wind that ended the weather station for the week. Not only that, it somehow broke my reasonably new deep fringe television antenna.
Not only broke the leading element beam down, but put it on the ground, twelve feet away.
Well, that ruined our television reception, but gave me an opportunity…
I knew I was going to replace that television antenna, so, I knew I had some nice long straight elements to play with.
The new antenna came in and I was ready to roll. I lowered my antennas and took everything down to the main mast. I had a new television antenna, new rotator, new television preamp and new coax for the television.
My chance had come. The 3 element 6 meter beam was going to get an upgrade. I was pretty excited to have it on the ground.
I searched all over for a 5 element beam calculator and was never happy with what I found. So I began searching for 5 element beam antennas and came across the Cushcraft A505S. The instruction manual had the dimensions where you could adjust the elements the particular frequency set of your choosing.
I chose the middle, 51.5-53 MHz. Then I worked out the math to find that my current beam length was perfect. I drew my little beam on the corner I printed of the measurements. And commenced to making two more elements as described above.
After that, I took of the original 3 elements and began measuring out from the very end of the beam. I then used those same self-drilling screws to reattach those elements in their new locations.
Continuing, I added the other two elements as before, with plastic cutting board pieces.
So there’s 3 directors, one driven, and one reflector element. No time to lose, I had a television antenna, 5 element beam and a dual band vertical for 2/70 to get back up in the air.
I’ll have to video my current method for my antenna mast, but for now, here’s a video of how I originally raised the antenna: http://www.youtube.com/watch?v=WsQO3UsR9wM
The mast has had several updates since then. I’ll have to do another article or video of all of that.
So here’s the end result, 3 antennas up on one mast that I think looks pretty good.
And now I wait…
Thanks for reading!
Very nice article and wonderful job building your 6 meter beams.
You may already know about this there is a website called dxmaps.com
There you can find real time postings of contacts or propagation for any of the ham bands. The posting come from dx packet clusters.
Here is the link to the 6 meter or 50 MHz page:
Have fun on the magic band and maybe someday soon we will have a QSO on six meters.
73 and Good Health, Jeff K9JP
Thanks John, K4AGO,
I am well aware of the close proximity and their detrimental effects. Unfortunately, I am stuck with such an arrangement for the time being. My current housing situation prevents me from doing what I’d really like, a tower or three. One day, I hope to have the optimum setup, but for now, I’m stuck with this.
I still get good TV reception, except when transmitting, and I have no comparison for my beam other than it’s current location. I suppose time will tell.
Thanks for your comment though. I appreciate the advice as I wade through the beginning, sort of, of the awesome hobby of amateur radio.
73, de KK4TIX, Greg.
As I was reading through your article, you had a slight “lingo ” difficulty. Where you said ” beam ” you meant to say “boom “. HIHI . No problem. Great article and I like how you cam up with everything. Love building antennas. Well planned out. Thanks a bunch. I may build two and try to make a gama.
Your article was really interesting. I have also built some yagi’s using tubing from old TV antennas. I have one question, though. I didn’t see if you installed a coax balun at the antenna feed point. I have never been able to tune my yagi’s to a low SWR without putting a balun at the feed point. What am I doing wrong?