HX Files 021

Hello and welcome to xtract 021 of the HX Files.

What to do

After making a few transceivers for use at home or portable, I was wondering what to make next? I was thinking what else would be of use, a beam or a vertical either one of them would be handy to have in the spares department, for the vertical aerial which typically is a slot type would involve some tools that I do not have in my workshop, so I decided that a beam it was is to be. While looking for designs of beams on the net I noticed that some of them were like the ones I have myself but only bigger, that was not the only thing bigger than  I have that I saw on the net ( towers , cars and of course an aerial). Some of the aerial designs were rather complicated to try as a first time project, but deciding  on the designs that were like my own was not a hard choice to make  so I had a look at the ones I use and decided to extend a couple of them. The conventional type of beam was not too bad to make as most of the basic parts were in stock, originally it was a 35el Tonna and now it is a 42el instead.  I already have a 55el at my home location but that aerial has two support arms underneath it I did not go to that trouble as I had not got enough of the tubing for the supporting framework. Working on that aerial was not too bad as a piece of box tubing the same size was in stock as was some of the standoff brackets for the elements. A couple of copper brazing rods were bought and a constructing we went. Having a ready made aerial was great as I could copy the extra piece of the beam that was to be attached to the 35el aerial. The elements were cut using a small hacksaw with the rod being held in a vice, the elements  were not all the same length  but there were a few of each that were the same size, and again having something to copy from was very handy but I still had to make sure that my markings and cuttings were exact. With that job done I had only to place the elements into their standoff brackets and make sure that the same amount of element was visible either side of the bracket. The new standoff brackets were bought at a rally some time ago for spares just in case some of the original ones were damaged. The brackets simply just clicked onto the boom, the original brackets had a small bump on them that fitted into a dimple on the boom which gave them the correct distance apart, the new ones had no bump on them and neither was there any dimples on the new section of boom but they were a tighter fit and seemed to offer a lot of resistance when I tried to move them, the distance of the extra elements were all the same as only the first few on the original beam had a different gap so I made a spacer out of a scrap piece of angle wood to match the gap between the elements .The other beam was originally a 15el loop aerial, and just like the other aerial, from element 4^th  to the last one were the same distance apart and the same diameter of loop. Copying the loops meant using some sort of a former to wrap the wire around to make the loops. As luck would have it I had a large diameter hole cutter (Photo 1 below) that was the same size as the loop, with only what to use to make the loop elements out of being the next issue. After a quick look through the store bunkers I found some rods and whips (I found them beside the fluffy handcuffs but that’s another story) that I could use for something to make the loops with. I was thinking of the odd lengths from some off-cuts of old and scraped aerials I had and also though of brazing/wielding rods, and even the loop of metal that is on the back of the hub caps found on some cars,  keep an eye on the side of the road, as with the one or two pot holes that are around the country have the habit of removing the odd hub cap, this wire is can also be used but it is rather rigid and springy  to bend around the loop former and some of them are of a different gauge of metal . The other lengths of rods and whips were also found to be rather stiff to work with and a bit springy, after a couple of close calls when the rods slipped from my hands and in one case hit the safety glasses I had on.

Time for Tea

It was then decided that the construction could wait and it was time to have a cup of tea or two and think of a plan B. During the tea drinking I was looking for something else and though of some electrical cable that comes in single strand, but of all the different cables I had none were single strand, a visit to Tony EI6IK and he had what I needed so after removing the outer plastic covering I used the electrical cable and wound it around the former, it started to look like a spring and after enough coils were wound on it the wire was cut and I had the loops that I needed for the job also seen in Photo 1 below.

The hole cutter partially embedded in a piece of wood for safety  

The elements before tiding up and soldering to bolts

 Photo 2 above shows some of the loops as each loop were cut off the spring like winding and the ends will be tidied up with a file. With the loops formed you then have to join the ends, this was done by brazing them together; the brazing was done for me by Kevin EI5JG, the two ends of the loop were joined together at the same time in the slot of a brass screw that a screwdriver slot in them. As mentioned earlier this job was extending the length of the aerial, and as the diameter of each element and their spacing was the same between each loop from the 5^th to the 101^st, whilst the strength of the new loops may not be the same as the original elements but they are good enough as they would be only used in a portable setup. A template was made that would help with marking and drilling the holes..

Worktop joiner

End profile of joiner, in the middle,and the two booms

 The template (Photo 3 above left) was made from a joiner used in joining kitchen worktops together, it has 3 holes in it from the manufacture one of these holes can be seen by the square drawn around it, but so far they have not caused any problems. 

In photo 4 above right, you may notice the joiner has a right angle on one side and a curve on the other side of it, the curved side will sit perfectly on round boom if I ever have to extend a round boom aerial. The old and the new extension booms  are 16mm x 16mm and were joined by some round tubing that was held in place by bolts on the original beam and rivets on the new section, the bolts can be removed easily  both for transporting and for the times that a big aerial is not needed. The first hole in this template would bolt into the last one of the original holes and the other holes used to line up, and then to mark (with the aide of a centre punch) the new holes onto the new piece of boom, and then the template removed and placed onto the last of the new holes and repeated until all the holes marked out that are needed. When installing the new elements the head of the bolt that the loop is brazed to can be held carefully by hand and the loop held parallel to the other elements while the retaining nut is tightened. I was lucky that on the second aerial being modded that a hole cutter I had was the right size.

The  new elements 

 In Photo 5 above you can see both the new elements ready for fitting; since the modded aerials were made I have used them on a few portable events and have noticed no difference in Rx and TX signals when I compared them to the factory ones of the same size.Whilst making the loop elements out of the copper wire I did notice that they were not as strong as the original loops and if the birds decided to rest on them the elements would bend and twist as the birds took off from them, so I decided to use the aerial upside down, it may give a better area for the birds but at least the elements would be okay.

And finally, thanks again to Kevin EI5JG for doing the brazing for me, and to Tony EI6IK for the element wire.

And may all your signals be P5.

The new boom before being cut to the required length