Congratulations, you have built the components for your hex beam; all that remains is to assemble them into a completed beam. If you have had the courage to take this construction project on, you probably don’t need the step by step assembly instructions. They are pretty much a mirror image of the assembly instructions we publish for buyers of the commercial version of the KIO beam. In fact, you can download them here and print them for convenience. And you probably also don’t need the precaution to avoid over tightening things. As you know, you can destroy mechanical things by over tightening. Now, here are the steps.
1. Set the base plate on a table, or a 10 gallon paint bucket filled with sand or rocks to serve as an assembly foundation. You can sink a one inch pipe in the ground and set the beam on it.
2. Insert the large spreader sections into the U bolts on the base plate. Tighten the U bolts evenly to keep the spreader straight and be careful not to over tighten. If you see the fiberglass spreader section flattening at all, you are over tightening it.
(Tip: Look across the beam to see if a spreader arm is lined up with its opposite. If not, then re-adjust the nuts on the U bolts to make them straight.)
3. Insert the medium spreader sections into the larger ones and push up to the stop clamp.
4. Repeat for the small spreader sections. Twist all sections so the P clips are on the upper side.
Insert the center post into the top flange on the base plate. Twist it so that the terminals are facing out from the middle between any two spreader arms. This will be the front of the beam and the two spreader arms will be designated #1 and #6 counting clockwise. Tighten the set screws on the flange to secure the center post. Again, there is no need to over tighten it.
1. Hook a support cord into the end of any spreader arm and pull it toward the center post and let it lie on the ground.
2. On the opposite spreader arm, hook another support cord into the spreader arm end, pull it toward the center post and let it lie on the ground.
3. Now, grip the loose ends of the two support cords and pull them together until you can hook them simultaneously onto the center post eye bolt. The idea of pulling the two cords together is to prevent stress on the center post.
4. Repeat this process for another pair of spreaders and support cords and then again until all six spreader arms and support cords are installed.
5. There are two remaining support cords. Hook the larger one between the ends of Spreaders #1 and #6. It will be loose but that’s ok, leave it for the time being. Also, the remaining short cord will be installed later.
6. Fasten the cords onto the spreader arm ends using the hose clamps as shown. With pliers, squeeze all the hooks closed on the post top. You now have the basic hexagonal beam shape established.
1. Beginning with the highest frequency band (the shortest wire set), at spreader #1, thread the wire set through the P clips for that band all the way around the frame until the last P clip on spreader #6 is threaded. Now take the two ends of the wire set and attach them to the band’s terminals on the center post. If they will not reach, just loosen the P clips on Spreaders 1 and 6 and let them slip in to provide enough slack to be able to attach the wire set to the terminals. When tightening the nuts on the terminals, use a second wrench or pliers to hold the nut beneath from twisting while you tighten the top nut.
2. Repeat this process for each of the wire sets continuing until all wire sets have been installed.
3. Adjust the wire sets until most of the slack is out of each of them but do not make them taut. The beam does not require taut wire sets and they just put unnecessary tension on the beam. On the other hand, do not let any wire droop down to the wire below as this will adversely affect performance. Adjustments can be done entirely on Spreaders 1 and 6 or if there is so much slack that this seems too much, all the spreader P clips for a band can be adjusted a smaller amount each to get the tension right. Remember, let the support cords do the work of holding the spreader arms in position, not the wires.
Final adjustment and tests
1. Install the last, smaller support cord with the hose clamps on it to pull the spreaders #1 and #6 back in line. Usually the weight of the wires will pull these spreaders apart and that is the purpose of both of the cords connecting these two spreaders. The initial location of the smaller cord is at approximately the 15 meter wire clip position. Adjust the location of the smaller cord to achieve the alignment of the two front spreaders. The shape and appearance is of little importance in performance of the beam so do not waste a lot of time fiddling with it unless you have a fanatical drive for perfect appearance.
2. Check DC continuity across the top two terminals of the center post. You should have infinite resistance. If you have a short, it is likely that a strand of coax somewhere has gotten across the cable.
3. Hook up a SWR analyzer such as the MFJ 259B with a short piece of coax to the pigtail and run a sweep on each band. You should be able to see a clear dip of SWR on each band. It might be a little lower in frequency than you prefer and it might not be as low a value as you would like, but the main thing is that you do see a dip. This tells you that the wire sets are cut right and that the beam is performing correctly. It’s a good idea to record this information on a piece of paper for future reference. Later when you raise the beam on the mast you should generally see a slight upward shift in frequency and improvement of SWR.
You need a Balun
It is a good idea to use a balun with your new hex beam. Place the balun near the feed point at the top of the center post or below the base plate. The balun reduces the flow of RF current on the exterior of the coax. This unwanted RF if unchecked, will distort the radiation pattern of the hex. A bead balun works fine and you can see more about this for a hex beam here. Or any other 1:1 current balun will do fine. If you use your own ferrite beads, type 31 is ideal and type 77 works fine too. You can fashion your own balun by simply coiling the feed line itself into about six turns of six inches neatly coiled as if wrapped around a Quaker oat box. Make it neat; a random coil won’t work well. Balun Designs and MFJ and DX Engineering all make baluns or you can buy one from us, of course.
You are done with the construction of your hexagonal beam. What’dya think? Now, on to erecting it on a mast. We don’t give you much guidance here; there are just too many possibilities. You can see a lot of actual installations here for inspiration and ideas of your own. A few points that we will make. When raising the beam handle it by holding it by the center post at about a foot above the bottom. Remove that small cord so you can stand there by the post inside the beam without getting tangled up. When carrying it up a ladder, go slow. The beam wants to grab every shrub and tree branch within a mile. Do not drop the beam on its side; it will definitely break a spreader arm, usually right at the base plate.
If you have to leave the beam on the ground overnight, expect that a deer will accidentally find it and get tangled up in the wires and cords.
Oh! Safety. You should have already researched the rules for safety with antennas and towers in the ARRL handbook. If you haven’t and are still alive, it is not too late to do this and pay attention especially to the stuff on power lines.