An alternative to the 6M7JHV antenna for 6m / 50MHz
Take a 1000mm length of 3/8" aluminium tube and make a right-angle bend about 200mm from one end.
Use a set square to set it accurately to 90 degrees.
Align this bent end of the loop end with the front side of the loop close to the beam and tape it to it. Then align the pipe bender as near as you can to the back of the loop as described on G0KSC's web site and shown in the photo below. G0KSC shows this being done at the end of the loop which looks a little easier but I think that the way I do it here will be more accurate. Mark the 3/8" tube to later align the pipe bender. Take the half inch tube out of the pipe bender.
Align the pipe bender so that the pipe will bend in exactly the right orientation to align with the first bend.
Now make the second bend. Which ever way you do it, make sure this one is correct (or have another attempt) as this the 'master'. Use this master to measure the second loop end. This is much easier and more accurate than making the 'master' in the first place. You then end up with two, hopefully, accurate 3/8" loop ends.
G4CCZ aligned his loops differently by placing short lengths of tube in the element brackets. This looks even simpler than the way I did it!
These can be now inserted into the ends of the two loop elements. Measure the distance between the long sides of the loop close to the boom and at the ends. These should be the same; if they are not it's back to the pipe bending!
Use a tape rule to set the front and back lengths of the loop to 2492mm - measuring to the outside edge of the 3/8" loop ends.
That's it for the loops. Simples :>)