Saturday, April 29, 2023

Building another YU7EF duoband antenna (1)

 As mentioned in the last post I'm building another duoband 6m/4m antenna for PB7Z Bernard. I have no scrap parts for this build and have to design everything from start. I learned from my own similair antenna build and want to make the antenna as good as possible.

Just to get the idea...

First challenge today was the aluminium tubing which did not fit the way I want it to be. Since I have to transport the whole antenna by car I need to cut the tubes for the 6m elements in half. To connect them together again I thought of sliding a tube of 10mm inside. This also gives the tube more strength in the center. However, instead of the expected inside diameter of 10mm it was 9,5mm. Drilling this to 10mm proved to be difficult since the drilling gives a lot of turning force on the tube. I didn't want to fix it in a vise, have tried it with a scrap tube but it gives a lot of damage even if I protect the tube, The risk of pressing the tube to an oval shape is also high. Holding the tube with my bare hands didn't work at first. But I found the solution after some experiments with ducktape which gave a lot of mess on the tube. The trick is to wear special high grip gloves. I used "Showa 380" gloves which are specially designed to hold small smooth or oily objects. They proved to be very good and drilling the tubes was no problem at all this way.

The gloves used
The 6m dipole so far. Insulated with a piece of teflon staff

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