An alternative to the 6M7JHV antenna for 6m / 50MHz
Like any DIY project you need to assemble the right tools to make the antenna. As Paul, G4CCZ says, the right tools make the difference between an easy job or a difficult one.
Fortunately for would-be antenna builders not too many are required and the specialist tool (pipe bender) only cost a few UK Pounds. antenna is around 9.7 Metres so a 10M rule is required. The reason for this is that antenna spacing should all be marked with a single extension of the tape rule. If a shorter rule is used it quite easy to suffer from cumulative errors thus significantly reducing the performance of the antenna. + or - 0.5mm accuracy or better is required throughout.
A small bore pipe cutter is required obtained from your local plumber's merchants or Ebay. Using one of these makes the cutting of the aluminium tube very easy and you can guarantee a high accuracy. Moreover, the cut is perfectly square and smooth as can be seen in the picture below.
Other tools you will require will be a hacksaw, centre punch, marking gauge and a divider compass a range of mm spanners.
A socket set is useful as well as spanners.
You will also need a set of Allan keys, screwdriver, small mire square, scriber and 6mm clearance and 8mm clearance drills.
Finally, although all the holes could be drilled with a hand held drill, I would really recommend using a bench drill to ensure accurate and square holes. If you don't own one, I would recommend hiring one.
A band saw is useful, but you can make do with a hacksaw.
It is worthwhile getting hold of some aluminium anti-corrosion paste to put on the 3/8" end part of the elements where they are inserted into the 1/2" tube - it is also used on the boom joiner.
The only specialist tool required is a small bore pipe bender. The designer of the antenna, Justin G0KSC suggested that these can be obtained from Ebay for very low cost which is where I obtained mine. Make sure that the bender you buy can handle 10 and 12mm pipe and you should be fine.
Warning and cock up! There seem to be a lot of pipe benders on Ebay. G4CCZ bought the expensive £12.95 version and I, as usual, went for cheap £4.95 version. Normally, the pipe is at right angles when you put in the bender, but with mine, the pipe sat at 20 degrees! I really could not understand why this should be so I had to file 5mm off the guide bar as can be seen in the photo below. So be warned! There are manufacturing rejects being sold on Ebay without any warnings! I'm not too worried about this as I doubt (ha!) that I will need to use it again. The seller was not too happy about the negative feedback I gave him!