HOMEBREW HEXBEAM PAGE
by W1GQL

 


 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dimensions

 

      All dimensions on this website are in feet and/or inches. If you are not used to working in feet and inches you can convert them easily. The symbol for a double quotation mark (") is an abbreviation for "inch". The symbol for a single quotation mark or an apostrophe (') is an abbreviation for "foot".
1 foot = .3048 meter
1 inch = 2.54 centimeter = 1/12 foot

 

     Here are the dimensions I use for my 20 Meter Hexbeams

 

     These dimensions agree with those of Holger Hannemann, DL7IO. My reflector is 448 inches long. My director is 434 inches long. His spreadsheet gives the dimensions of 569 cm for the reflector and 551 cm for the director. His figures are for only 1/2 of each element. (569 times 2 = 1138. 1138/2.54 = 448) You will find other dimensions on the internet. I have no doubt that other dimensions will "work". I know that mine work well. Mike Traffie's original articles say that the reflector formula is 6262/frequency in Mhz. 6262/14= 447.2 inches. So the reflector length is almost exactly the same. His director formula was not as specific. It was 6160-6190/freq in Mhz. This corresponds to 440 inches to 442.14 inches, where whereas Holger and I use 434. I intend to investigate the results of these different lengths and report them here. Preliminary tests indicate that the gain is a little better with my shorter director lengths.

     The other dimensions I use are not dimensions of wire, but rather of spacing. The tips of the ends of the driven element and the tips of the ends of the reflector should be about 9 inches to 10 inches apart. My EXNEC model actually has the tips 9 3/4 inches apart. My actual antenna turned out to be closer to 9". From my experiments with the EZNEC model, I see no real difference between them. My model has the centers at the feed point about an inch and a quarter apart. One of my Hexbeams uses approximately that dimension, and the other uses the 1/2 figure. Again, I can not see a significant difference. In the end it will probably depend on the type of center post you use. With a 1 1/2" to 2 inch center post, it would be hard to get the centers really close. If you use my plexiglass offset method described below you can set your center spacing at will. If I were you I would not worry too much about it.

     The 5 7/8" and 3 15/16" dimensions are the lengths of the insulating material you use between the tips and the connection point on the spreader. See the section on "Tip spacing" for more about them.

     Another observation is in order. I suggest that you do worry about two legs of an element being, say, 109" long and the other two being 115". It is the total length that is important, 448" in the case of the 20 meter reflector. These 109" and 115" leg dimensions pretty much take care of themselves as you build the Hex. Just attach the center point of the 448" inch reflector at the hub, and attach the tips with the correct spacing. Then all you have to do is find the approximate middle of section of wire between the hub and the tip and pull it out toward the end of the spreader that is between them, forming an apex or V out on the spreader. When you pull it so that the two legs are straight the 109" and 115" numbers take care of themselves. In my experience they are not critical. How you connect the V point to the spreader is up to you. I actually have just used a cable tie and attached the point right to the spreader. I used a little tape to keep the cable tie from slipping back down the spreader toward the hub. Some people use more sophisticated means, but my method works.

 

Spreaders

 

     I have built five Hexbeams using three different types of spreader. For the first one I used 10 foot sections of 3/4 " ID PVC water pipe. The second used spreaders originally made for cubical quad back in the 1960's. A friend of mine bought them and then never got around to putting the quad together and sold them to me about 40 years later for a very reasonable price. They are made of fiberglass and came 13 feet long. The third Hexbeam I built was a portable for use on trailer trips that used telescoping fiberglass "Crappie" fishing poles. I bought 6 of them on Ebay for $20.50. The fourth was a 30 Meter Hex that had no actual spreaders. It was built using 6 vertical poles holding the extremities of the elements. The poles were stuck in the ground. Even at about 7 feet I worked all over europe with it. The fifth was a 30 Meter Hex that re-used the crappie poles and was made with the elements wound in loose helical fashion around the supporting nylon cords. Even though it is for 30 Meters it is slightly smaller than the 20 meter versions. Check for more information about it elsewhere on this website.

     The quad spreader version is obviously the best of the hexbeams I have built. (Here is a nice shot of it in the air.) If my friend had not had the spreaders for sale I don't believe I would have spent the money to buy brand new heavy duty fiberglass poles. I am "cheap", you might say. You may have seen the August 2005 issue of QST which featured an article on building a 17/12 meter Moxon antenna. The author used 3/4" and 1/2" outside diameter 1/8" wall fiberglass tubing. I am sure they would work, although I am not sure I would use 8 foot sections of the 3/4" because I think that when I put the bow in the spreader it might tend to bend too far out on the spreader at the junction of the 3/4" and 1/2" segments. I would have to experiment and see if that would be the case. I might try buying 4 foot sections and then using a dowel of some sort to splice them. (I checked and found that the shipping charges on longer poles is VERY high.) I guess I would have stuck with the PVC water pipe version with some modifications.

      The PVC pipes are really not stiff enough to use alone. They tended to droop when the temperature went up. They also would twist easily. What would happen was that you would have all six spreaders tied up so that their ends were pointing up in the air and then they would all twist to one side so that all the ends were now pointing horizontally. I solved this problem to some extent by putting a couple 2 foot "outriggers" on my hub and running cords from the ends of the outriggers to the ends of 2 opposite spreaders. This gave the ends some horizontal stability.

      I also was planning to stiffen the PVC spreaders by putting some wooden dowels inside them when my friend offered his quad spreaders and I decided to abandon the PVC version. I am convinced that I could make a satisfactory Hex using this method, however, and intend to experiment with it some more.

     The quad spreaders were each 13 feet long. Since a 20 meter Hex requires appx. 10 foot spreaders I reluctantly cut them shorter. (They were so nice that I hated to do it!) I ended up cutting 2 feet from each of them. I cut some from each end since this allowed me to cut them in areas that the manufacturer had reinforced somewhat.

      My method of building a Hexbeam is different from other methods I have seen. I do not use the wire elements as structural components. They do not help hold the spreaders in position. I hold the spreaders in position with nylon cord and then simply suspend the wire elements in the cage I have made of spreaders and cords. Because of using this method, it is not at all critical if the spreaders are extra long. Just make sure the are long enough to accommodate your elements when bent. The leg of the "W" in the reflector of a 20 Meter Hexbeam is 115 inches (or 9.5 ft) long, so the tip of your spreader will have to be at least that far from the center post, measuring, as in the picture, straight out at a 90 degree angle from the post. I would allow somewhat more than that, especially if you choose to use my slightly offset feed method. If you are planning on added other bands below the 20 meter element, your spreaders may have to be longer than 10 feet because the bend will not extend high enough to make room for the other bands' elements.

      I have done some experimenting with bowing. I find the results interesting. Bow a 10 spreader so that the end is one foot up and you only loose one inch in length. Bow it up 1 1/2 feet and you lose around 3 inches. (These distances vary somewhat depending on the shape of your bow, but don't vary more than an give or take an inch.) Bow it up 2 feet and you lose about 5 inches. Bow it 2 1/2 feet and you lose about 8 inches. This means to me, in practical terms, that one can expect to be able to bow a 10 foot spreader up only about 2 feet and still have room for the elements of a 20 meter Hexbeam. If you figure that the hub end of the 10 foot spreader is going to be out maybe an inch from the center of the hub (to allow for the center post), you might be able to bow a little more than 2 feet up, but not much.

     Before I began to build my first Hexbeam I read as much as I could find about it on the web and noticed that a number of people had ended up with cracked spreaders at the point where they tightened them down to the hub. I decided to protect my spreaders from cracking by slipping a piece of plastic tubing over the end where it sits on the hub. I found just the perfect diameter clear plastic tubing at Home Depot and used a few a few inches of it on the end of each spreader. I did the same thing on the crappie pole version. It is probably more important there, since the fiberglass in the crappie poles is VERY thin.

     I have seen several postings on the Yahoo Hexbeam group asking if the spreaders actually have to bend. The answer is "no", if you only plan to make a mono-band Hex. The primary reason for bending the HEX spreaders us is to provide room for more than one band's wire elements with some vertical spacing between them. The answer is "yes", if you do not plan to provide some support in the form of guy lines from the top of you center post to keep the ends of the spreaders from drooping down. The answer would also be "yes" if your hub contains any metal, because the metal would interfere with the feed point which is right in the middle of the hub.

      I have thought about the possibility of using a non-bent spreader with a little support for wire attachment rising at right angles from the spreader at the end. This is something like what they did in the Moxon article. It would require extra guys and I don't know what would be gained. It might be worth trying, however.

     I have also seen questions on whether the spreaders have to bow up. Can they bow down instead? Again the answer is a qualified "yes", but people who have tried it find two problems, both related to the question above. When they bow down they just tend to droop badly and you can not use a metal mast because it would interfere with the feed point. Return to Top

 

Hubs

 

All three of my hubs have been circles of 1/2" plywood. The hub for the PVC version was two feet in diameter. I had decided to make it that large because I thought it would help support the easily bendable PVC better. Perhaps it did, but it also weighed too much. For the quad spreader and crappie pole versions I used a hub of one foot. I was in a big hurry when I built the quad spreader version and did not take the time to seal the plywood adequately. What has happened with that hub is that it has "cupped" under the stress of the bent-up rigid fiberglass poles. After a Maine winter the poles are actually straighter than they initially were and the entire pole goes up at an angle more and there is less bending at the end. If it were a serious multi-band Hexbeam (It does have a 17 meter element which is fed with a separate coax), this change in geometry would be a problem, I am sure.

      If you have trouble laying out the six spreaders on your hub, it would pay you to review your high school geometry. In geometry class we learned to set our compass to the radius of the circle we wanted to draw, then use it to draw the circle. With the compass still at the same spacing we could put the metal point at a spot on the circumference (outside edge) of the circle and with the pencil end of the compass make a small arc across the circumference part way around the circle. It just happens that, if you then put the metal point at the intersection of the small arc you just drew and the circumference and make a second arc further along the circumference, and keep doing that until you get back to the point were you started, you will have divided the circumference of the circle into exactly six sections. Since a Hexbeam requires six spreaders this makes a perfect way to position them around the hub.

Here is a rough sketch of the layout procedure

 

Here is the hub of my second, quad spreader version

 

     You will notice some extra holes in this hub. It started life as one of the plywood ends on a spool of wire. The spreaders were originally an ugly mustard color. I painted them with flat gray spray paint. Note the clear plastic shields. The black marks on the clear plastic indicated the Up direction of the spreader so that the slits I cut in the far end would be horizontal. The spreaders are held on this hub by U-bolts. The first PVC version's spreaders were held on with thin metal "U" shaped clips designed to hold 3/4 inch copper pipe to wood. The portable crappie pole version's spreaders are actually held on with cable tie fasteners from an auto parts store.

     Some day I hope to get a one foot diameter circular plate of 1/4" or 5/16" aluminum for a hub. I think it would be the ideal solution. My friend Caleb, WA2JJX, made his first hub out of fiberglass. That is another possibility. Caleb has access to fiberglass through his business. That helps. Return to Top

 

Center Post

 

     There are several options for the center post of a Hexbeam. Many people use a PVC pipe. Sometimes people who build multi-band homebrew Hexbeams put their feedline inside the pipe and use brass bolts through the pipe to connect to the wire element. I have used two different types of post. My first two Hexbeams used a section of round 1 1/4" wooden "closet rod" from the hardware store. My wonderful portable "crappie pole" hex just uses a section of 3/8" flexible (nylon? teflon?) tent or beach umbrella stay that I found at the local dump (they call it a transfer station now and it is much harder to "pick the dump" than it used to be!) In the PVC and quadspreader versions of the Hex, I used cords from the top of the center post out to the ends of the elements to help hold the spreaders in their bent position (remember that I don't use the wire elements to do that as most people do. In the "crappie pole" version I found that the cord around the perimeter of the Hex, running from one spreader tip to the next, was adequate to hold the spreaders in their bent position.

     I think if I were to build another PVC pipe hex I would also run guys from the top of my center post to points half way out the spreaders to help deal with the PVC's tendency to droop especially when the temperature is high.

     If you plan to run guys from the top of the center post out to the tips of the spreaders, then you will have the post longer so that it will extend up above the height of the wire elements. Here is the center post with the guys going out to the spreader tips on my quad spreader Hex. The metal ring you see on the top was something I found in my junkbox. It was once part of a now dead two meter antenna. If you need no guys, then the post can be cut to be just an inch or two higher than the wires. Return to Top

 

Wire to Use

 

     I have made dozens of wire antennas over the years. With only a couple exceptions I have used #12 or #14 copper wire stripped out of household wiring "Romex". I have been very lucky to find nice lengths of Romex at yard sales and junk shops. I have always stripped the wire completely. I do this by first using a utility knife to cut a slit the whole length of the plastic jacket. Sometimes there is a bare ground wire inside that is ready to use. To take the insulation off the white and black wires I usually tie one end of the wire to a post or tree in my yard and then pull the wire straight. When it is straight it is easy to pull the utility knife along the wire cutting a slice of the insulation off down to the bare wire. The rest of the insulation will stay on the wire but can be easily pulled off at this point. Very often the wire is quite kinky. You can easily straighten it by wrapping it part way around a pipe or dowel (or hammer handle or whatever) and while pulling hard on the wire (still tied to the post) with the pipe. Let it slip around the pipe as you pull and you will be surprised how straight you can get the wire after a couple passes.

     All of my computer models of the Hexbeam and my first two actual Hexbeams have been made using number 14 wire. The wire is not hard drawn and can stretch, but because I put no load at all on it, using my method of building a Hexbeam, this is not a problem at all. For my portable Hexbeam I used some soft stranded copper wire that I had picked up at a hospital rummage sale. I love it! You can buy soft stranded copper antenna wire from several companies that advertise in QST. One of the best is called "FlexWeave", I believe. When my ship comes in, I am going to buy several hundred feet of it. Return to Top

 

Tip Spacing

 

      The spacing between the ends or tips of the driven element and the reflector in a Hexbeam is a concern. Some sources say that the spacing is critical. I have experimented with the EZNEC antenna modeling program and found that changing the spacing a few inches either way makes negligible difference.

     Most web references to the tip spacing quote three figures. The longest of the three is the distance drawn in a straight line between the tip of the reflector and the tip of the director. To me this is the important dimension. In my Hexbeams I maintain this distance by actually tying a cord of the appropriate length between the tips and them making sure when I "string" the Hex that the cord is taught. The other two dimensions have a much more important role if you are actually using the wire element to connect the spreaders. The middle dimension of the three is the length of the insulating connector that goes from the tip of the driven element (in a straight line with the wire) to the attachment point on the spreader. The shortest dimension of the three is the length of the insulating connector that goes from the tip of the reflector wire to the same point. If they are done correctly the distance in a straight line from the two tips should be the same and the longest dimension mentioned above. Here is a diagram that I found on the web. (Sorry I can't remember where. My apologies!) I shows that the tips should be 145/frequency inches apart. For 14 MHZ that would be 10.35 inches. I built my Hexbeams using DL7IO's figures and I use a spacing of 9 (or 9 3/4)". It does not seem to be super critical. I have not paid a lot of attention to the smaller two of the formula dimensions. Look at how I have handled the tip spacing. You will see that I make a triangle out of nylon cord and use it at the tips. As long as the long side of the triangle is tight I know my tip spacing is what I want it to be. The other two sides of the cord triangle do now have to be cut to any special length. You will see that they do not necessarily line up with the wires even.

     You will note in the last illustration that the ends of the wires are formed in a loop. After I built this Hex, I read some material by W4RNL on the Hex and Moxon antennas and he said that best results are attained it the tips of the elements are plain with no thicker areas such as my loops. So my subsequent Hexbeams have handled connecting to the tips in a different way. See the section on Connections.

     I must mention that all of my operating using my Hexbeams has been at power levels under 100 watts. I know that Mike Traffie has stated that good insulators must be used when building a Hex because of the high voltages. I have had no problem with my nylon cord insulators at the tip ends, but can not say what might happen if I were running the legal limit. If you intend to run high power with your hex, you may want to look into the insulator issue. If any one reading this can shed any light on the issue I would appreciate hearing from them.Return to Top

 

Feeding the Hex

 

     When I built my first Hexbeam I was anxious to see how well it worked and got a little sloppy toward the end of building it. I found a plastic pipe fitting that would slip over my wooden closet rod center post and then tied my elements to it. It looked very messy but worked wonderfully. I later added a separate 17 meter Hexbeam to the antenna, feeding it with a separate coax. For the 17 meter Hex I developed a simple method of handling the feed point that works extremely well. Although the center of the Hex is offset by a few inches using this method, I have not been able to see any difference in performance at all. I used a 2" by 3" piece of 1/4" plexiglass and drilled holes in it to pass wires through. I think the pictures make it clear what I did. Here is a picture of the plastic in use before I sealed the coax end. Other people have used my method and report ease of use and no problems.

      Feeding a multi-band Hexbeam is another issue. You will find articles on the web telling about trying to fish wires and bolts down inside PVC center posts with difficulty. I probably will eventually try to build a multi-band Hex but for now have decided that the simplicity of my method of the plastic hub and feeding bands with separate coax works for me. My friend Caleb, WA2JJX, has used my method for a 20/17 meter Hexbeam and he likes it very much. Both of us actually do not bring 2 coaxes into the shack, but use remote antenna switches. My switch is mounted at the base of the antenna on a pipe. Caleb mounted is up on the mast of the antenna below the hub. I would love to have people send me details of their Hex feed points, especially for multi-band units. I will feature them here on my webpage. Return to Top

For my portable version of the Hex I used the plexiglass feedpoint, but with a different twist. Since my center post was a thin rod I decided to drill a hole right through the middle of the plexiglass and slip it down over the rod. It just fits and worked out wonderfully.

 

Construction

 

     I do not build my antennas for the ages! I admit it. I love playing with antennas so much that I know I will be making changes soon or will come up with a new antenna idea long before my current antenna falls apart. If I were planning to put my Hexbeam up on a fifty foot tower and use it for 20 years, I would do things differently, I am sure. I put mine on a homemade tiltover tower and can have it down for repairs or changes in five minutes.

      In any case, I would like to share some insights that I have had while building three homebrew Hexbeams. The first thing to remember is that the Hexbeam is an inherently light antenna. So keep it light. Don't over build it. There is no need for that. You can attach your plywood hub to a mast using three small L brackets. They work fine. My first two Hexbeams used an aluminum hand-rail bracket designed to attach the end of the rail to a wall. I had it in my junk-box so I used it. WA2JJX sent me pictures of his Hexbeam and I saw that he had used three small L brackets. I tried his idea on my third Hex and found it very handy. Caleb did not even screw the brackets to the mast but rather used a couple stainless steel pipe clamps. That way the hub can be easily removed from the mast. Try it!

      How do you attach to the end of the spreaders? Building my PVC and quad spreader Hexbeams I cut a slot in the end of the spreader. This was a convenient attachment point. I really could not cut a slot in the end of the crappie fishing pole used for my third portable Hexbeam. It was just too small and fragile. Instead I had some pieces of hollow fiberglass rod left from cutting off the ends of the quad spreaders for Hex number 2. I found that they just slipped nicely over the end of the crappie pole. I cut off a piece about 2 inches long, drilled a hole through it, put a short length of copper wire through the hole and soldered it into a loop. Here is a picture.

     My quad spreader version has spreaders that are 11 feet long, quite a bit longer than they need to me for a 20 meter Hex. I have nylon cord running from the slotted tips of each spreader to the adjacent spreader tips and also back from each tip to the center post. The wire elements are attached to the spreader using cable ties with a little duct tape below them to keep them from slipping. Note that the wire elements are not under any stress. They are rather loosely strung in the 'cage' of spreaders and cords.

      Before you try to run the perimeter cord around the outside of the Hexbeam, take time to string out the cord straight and mark off, with some sort of indicator, the points where the spreaders tips will attach. I suggest carefully tying a small loop at all six points. (You will actually need seven loops, don't forget.) Allow for the length of cord needed to make the loops. When you are putting the Hex together, bending up each spreader, you can then just slip a loop into the slot at the spreader end. This makes bending the spreaders up MUCH, MUCH easier and guarantees that they will be evenly spaced.

      When you are ready to slip the last loop on and complete the circle of bent up spreaders, you may have to put some sort of support under the opposite spreader from the one you are working on. If you don't the spreaders on the opposite side from you will want to bend DOWN because of gravity instead of UP.

      I would love to find some sort of plastic or teflon connector that I could use to attach the straight end of a piece of #14 wire to a piece of cord. I want to avoid putting a loop or any kind of bump at the end of the element. I notice that DL7IO in Germany sells something like I want on his webpage. I have devised a method to attach them that works for me and has worked for my friend Caleb. Take at look This works for me. If my elements were under stress and holding the spreaders themselves I doubt if it would be satisfactory. (My cord is actually Nylon, not Dacron.) As I noted elsewhere, one of my Hexbeams had the end of the elements soldered into a loop and I really have not noticed a difference. Supposedly it affects the coupling of the director and reflector ends.

     Most Hexbeam users seem to use some sort of balun in the feed line. I am not convinced that it is necessary, but most people think that it helps eliminate the tendency of a beam antenna to have a pattern distorted slightly to one side. The simplest balun to use and one that is pretty much foolproof is the common mode choke balun made by just coiling about 8 feet of the coax going to the Hexbeam into 7 loops (turns). Don't worry about the size of the loops. Their size will be taken care of "automatically" when you make the required 7 loops. Here is a (little bit fuzzy) picture of the finished product. This sort of balun does not even require any coax fittings! It is not mandatory, but supposedly the balun works best if the coils are neatly arranged side by side. You can use electrical tape to hold them. I often lay a small piece of plastic across the coils and then tape over the plastic. This balun covers 14 to 30 MHZ. To cover 3-30 MHZ use 10 feet turned into 7 turns.Return to Top

 

Possible Masts

 

     I have always had more trouble figuring out how to get my antennas in the air than I have had dreaming them up and building them. A few years ago, on moving to my current location, I bought a slingshot and after missing many times managed to get line over some trees in the back yard. Those trees now have pulleys up in them. But I didn't think a pulley would help me get my Hexbeam in the air. I was wrong.

     Seven or eight years ago I designed the "Gull Wing" Extended Double Zepp antenna and hoped to get its apex up about 50 feet. I never did. I had bought 3 20 foot lengths of PVC drain pipe at 2, 2 1/2 and 3 inch diameters. I built a telescoping mast with them and invited several friends over to help me erect my pole. Unfortunately the pole ended up bending over double and we had to give up. I kept the pipes but did nothing with them for years.

     When I was ready to put my Hex up I decided to try the PVC pipes again but this time was only aiming at about 30 feet. I sunk two PVC 10 foot pipes (An electrician had installed an underground AC line to my house and used pipes like this to run down the side of the power pole at the road. These were left in my yard, so being the pack rat that I am, I had put them into my junk pile.) I sunk them each in the ground about 2 and a half or 3 feet and about 6 inches apart. I them drilled two sets of holes through the pipes so that the holes lined up and I could but a steel rod through them, one for a fulcrum for my tilt-over pipe tower and the other for a crank at the bottom. It doesn't look very elegant but it does work.

     When I tried cranking up the tilt-over pole with the Hexbeam and small rotor on top the PVC pole did its old trick of bending over almost double. Finally I solved the problem by running a line from the pulley up part way on a 125 foot old spruce tree in the side yard to near the top of the pole and alternately pulling on the line and cranking at the bottom of the "tower". Up she went! I have had it up and down dozens of times since with no problem. I wouldn't recommend this method, but it does work.

     My portable crappie pole Hexbeam goes up to about 20 feet on two 8 foot sections of 2 inch OD aluminum tubing rescued from an old full size 20 meter yagi I bought at a swap meet. The two sections are joined with a section of 2" ID PVC drain pipe that slips beautifully over them. The rest of the 20 foot height is another short section of the PVC. Eight foot sections are a bit long for portable use, but I do tow my trailer with a Chevy Suburban that will accommodate them.

     I really like the "tower" that my friend Caleb WA2JJX built for his Hexbeam. He was able to buy a 20 foot section of aluminum pipe. His arrangement also tips over, but he uses a little winch and he mounted his little rotor at the bottom of the pipe. Here is a picture. Caleb calls this antenna "Crappie Martha". He built his first Hex using bamboo poles. I had told him that Joe N9PH called his bamboo Hex Martha because he bought the bamboo at K-Mart where Martha Stewart sells. So Caleb called his first Hex Martha II. Martha II died when he snapped a bamboo pole while taking her down for adjustment. The Hex in the pictures is built with Crappie Telescoping Fishing Poles bought on Ebay. So Caleb calls her "Crappie Martha". She is a beauty.

     Hexbeams weigh very little. My crappie pole version weighs less than five pounds and my quad spreader version weighs in about 10. There are telescoping masts on the market that will easily accommodate this weight. Mike Traffie sells one on his website. As I find information on others I will be adding it here.

     I saw one posting on the internet that told of suspending a hex on ropes strung between two trees. I can see how that might work.

     If you have any other ideas on masts for a Hexbeam, let me know so I can share your idea here.Return to Top

 

Multi-Band Hexbeams

 

      Two of my Hexbeams have been multi-band versions. Both of them have elements for 20 Meters and 17 meters. Here are the dimensions I used for my 17 Meter Hex. I chose to feed them separately, with two coaxes. The coax runs to a remote antenna switch at the base of the pole. This is a simple and very workable solution.

     Judging from the postings on the Yahoo Hexbeam group, a lot of people want to build 5 band versions covering 20, 17, 15, 12, and 10. Mike Traffie sells one that has these 5 bands and I hear it works very well and is remarkably well built. I know from my reading and talking to Mike on the phone that he spent years playing with the dimensions for the various bands and feeding system. He uses a single feed line. His feedline goes to the top (20 Meter) section. He found that he could get it to work for 2 bands and then when he tried to add the third he would have to go back to the drawing board and change the dimension of the first two again. The same thing happened when he add the fourth and fifth bands, only he had to readjust more earlier ones. You have to give him a lot of credit!! From what I understand, his final dimensions vary considerably from what the dimensions would be for a single band Hex. You can not just simply add bands.

     DL7IO has information on his webpage for making various multi-band Hexbeams. I am sure that I will try building one at some point. He feeds his multi-band versions from the bottom, so his dimensions are not the same as Mike Traffie's.

      Before you go ahead and try to build a multi-band Hex I suggest that you first build a single band version. If you don't want to have to do it again, you may want to make sure that the spreaders you use will be long enough and bend up enough to accommodate the elements for the bands you want to add later. And remember, the chances that you can just add a second band to be fed with the same coax as the first, and not have to adjust the lengths of the first band's elements, are next to zero. The antenna may work but the feed point impedance will change your SWR so that it is way off.

      I would say this, though, that to me it makes very little sense to build a Hex for 15, 12, or 10 in 2005. These bands are not going to come back alive for a number of years. Building an antenna for them now and exposing it to the elements for years before you can take advantage of it just doesn't work for me. As of this writing, at the end of July 2005, even having an antenna for 17 meters is not a big plus.

     If you want to add bands, why not focus on figuring out how to build a Hex for 30 Meters, or better yet 40. A handful of people have built one for 40 Meters. DL7IO has built several. He recommends that a 40 Meter version be 50 feet high. The problem with an 80 meter Hex, besides its large size is getting it up high enough. DL7IO has offered to help someone build one if the person can guarantee he can get it up at least 90 meters. Return to Top

 

How High?

 

     Check Mike Traffie's web page and you will see that he compares the Hex at 40 feet to antennas much higher. Mine is at 28 feet and I have had no reason to try to put it higher. Way over 90 percent of the time I call someone they come back to me. Why pay to stick something higher in the air. I would say to aim for at between 30 and 40 feet, but if you can't make it don't worry. I have had my crappie pole portable Hex set up along side the quad spreader version. The Crappie version was at 20 feet and the other at 28. I could not detect any difference in signals.

     Go higher if you want, but check my section on Hex characteristics before you do. You will see that as you go up to 50 or 60 feet the pattern starts to break down and a lot of energy is aimed way up in the sky and won't do you a lot of good. You do gain a lower take-off angle, naturally, but the additional signal at that angle is about 1 decibel more, that is 1/6th of a S unit and the smallest difference in signal that a human ear can detect. I don't think it is worth it. See my section on "Patterns".Return to Top

 

Rotor Options

 

     My rotor is an old Archer TV rotor from Radio Shack. I see that MFJ advertises a similar looking one in QST. It is the cheapest rotor they sell. My has been up during an entire Maine winter and is no worse for wear. I think you will be amazed at how little the wind bothers a Hex. They are completely symmetrical so there is very little twisting force from the wind. The Hex will gently swing back and forth a little and that is that. Any regular yagi is much more affected by the wind. It is much more likely to act as a weather vane and try to swing so that it shows the least resistance to the wind. A Hex has no tendency to do that. A Hex is also so light that almost any TV antenna you find will way more. Return to Top

            
            
            
            
           
I got some of the ideas for the format of this page from Dry-Rain. Check them out!