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Below you will find a number of photos on my current antenna project.
I am building a 8 element loop yagi antenna, and a tube bender to form the loops.

For info mail  edwinvanluijk@planet.nl

This is the tube bender to create the loops. It's build to PA5RWE's design.

  The replica build by me ==>

Construction of the tube bender in steps

View of the bottom plate
All components will be mounted to this plate. It's constructed out of stainless steel.

 

 

 

 

 

 

 

 

 

Another view of the construction. On the bottom plate, the mounting to mount it on a workbench can be seen.

 

 

 

 

 

 

 

 

 

Nylon pulleys are being used to guide the tube. Each pully is mounted on it's axle using two bearings to insure smooth movement of the pully.

 

 

 

 

 

 

 

 

 

To control the radius we need to control the pressure of the center pully.
The pulley is mounted with two bearings to the stainless steel triangular construction, which is mounted to a solid stainless steel axle.
This solid stainless steel axle is mounted in two bearing blocks, so that it is able to slide across. Pressure is controlled by turning the black knob. Turning will it clockwise will move the jack screw towards the bearing blocks, increasing the pressure, making the radius sharper.

 

 

 

 

 

 

Front view of the pressure axle. You can see the bushing in the bearing blocks.

 

 

 

 

 

 

 

 

 

 

The lever to feed the tube through the pulley.
Still need to install a sprocket on this fixed pulley, to drive the second fixed pulley. This is needed to prevent the aluminium tube from slipping while forming a loop.


 

 

 

 

 

 

 

 

Wanted to use this set of sprockets and chain. However found this sprockets so hard to drill that I went for another solution.
Found some double sprockets and a chain which fitted, so decided to use this setup.

 

 

 

 

 

 

 

 

 

 A ruler is used to measure the setting of the pressure axle. This is a measurement which represents the pressure, and the radius for a given tube.
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This photo gives a clear view of the tube bender. It isn't finished yet as the chain and sprockets haven't been fitted yet.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Why do we need this tool ?, To make nice round loops for Loop YAGI
In the photo under this text you see a finished loop yagi build by PA5RWE

 

Received the aluminium tubing, now we can start creating loops.

8 tubes with a length of 2.50 m, diameter 10 mm, and a thickness of 1 mm.

1 tube with a length of 4.25 m. diameter 40 mm, and a thickness of 3 mm.

To test the bender, I used a test 10 mm tube with a length of 1 meter

The loop is very nice round. This one has diameter of 30 cm.
It also suites my dog very well. Don't you think so?

The loops for my Loop Yagi

Needed plastic distance holders to mount the loop onto the boom.
Lucky enough my employer had some plastic gears, normally used in a packing machine.

On the drawing you can see the distance holder supporting the three rods which will hold the loop in place.  

I needed to remove the teeth of the gears. A lot of work, as it is made from strong and hard material.
The rods which will mound the loop to the distance holder are from fibre glass.

I bought the rods with a length of 1,5 meter and saw them to the correct length.

Finally!, The first loop is mounted on the boom. Will have to mount the other seven loops in the same manner.
All loops are installed onto the boom. Next thing is the polarisation rotor which will have to be made. It will be a complicated job.

   

  

  

Next thing is the assembly of a coax cable to the radiating loop.

   

Pressed two solid aluminium bushings in the loop ends. A screw will be installed into the bushing for contact with the coax cable. The end pieces should be kept 1 cm apart. I used a glassfiber rod which I taped to the loop, to maintain the spacing.
   

THE END