New Elementholders constructed by Aage, LA4ZH
|Type 1 for imperial sizes:
Square boom: 0.75(19.15 mm) - 1(25.4 mm) - 1.125''(28.57 mm) - 1,25(31.75 mm)
Round boom: 1(25.4 mm) -1.25 (31.75 mm)
Elements: 0.25(6 mm) - 0.55(14 mm)
Type 2 for metric sizes:
Square boom: 15/16 mm, 20 mm, 25 mm, 30 mm
Round: 28 mm, 30 mm
Elements: 6 mm - 14 mm
An ingenious construction, fits for several sizes of booms and elements! For square and round booms, good stability. Element mounting high enough (always > boomdiameter/2) above the boom, for 6 m and 2 m you do not need a correction factor.
Soon available at www.eidolon.no
Elementholders für 8-mm-Aluminium-Tubes made with Fence Insulators
|For meadow fences are several types of UV-stabilized insulators
abailable. The two types shown are ideal for mounting 8-mm-elements on a
bigger boom than 20 mm. As you know mounting of elements close
above the boom will lead to a frequency shift, which is not easy to
handle. With these insulators the elements are high enough for 25-, 30-
and 35-mm-booms (round or square) without needing a correction factor.
The cheap insulators are made in China (of cause...) and I think not only available in Germany. The costs are 0,215 and 0,39 per piece. Here is a link you can see more details: Insulators For portabel mounting the elements are clipped only, you can fix them for permanent installation with two small screws at each side. Because the mounting is made in the electrical zero voltage points (current maxima) you have absolutely no problems with the black carbon stabilized polyamid. Only if you would use these holders at high voltage points (e.g. at the dipoles outer ends) you could get problems, but with Yagi antennas in the middle of the halfwave-elements an ideal method.
The left picture with a 25-mm-boom shows how the element is clipped, with turning 45° to the right the element is fixed. By clicking on the thumbnails the picture will be shown greater. Three different types are useful as holders for 8-mm-tubes.
Here is shown how the element is fixed with two screws
It is possible to mount aluminium welding rods, too.
Look at the picture!
This is another type of these excellent holders
The picture shows an 8-El.-2-m-Yagi (28-Ohm-OWM-Yagi) with these insulators