Spider-Beam 11m - Projekt
Hi there,
here I am back with another directional antenna project for the 11m band. The bad thing is
on my 2-element quad, they must be very high up and a large area. Unfortunately, the house stands about 70m further away and then the amount has yet to be observed - all require at least 100m thick RG238U coaxial cable.
why I am now decided on a Spider-Beam. Which is lighter and does not need too high.
The calculations are always the same.
mechanical length of the wires resulting from the known formulas for the quad or Dipolberechnung. For those who like simple, using one of the many calculators, such as http://www.qsl.net/yt1vp/CUBICAL 20Quad%%% 20ANTENNA 20CALCULATOR.htm .
When Spider-Beam is important to note that it takes only half the wire. So for the driven element (spot), only 5.61 m instead of 11.22 m as in the quad.
The carrier must cross it to be larger. 2.81 m per spreader arm instead of 2.03 m as in the quad. For this is
realize the holder construct easier. Simply take a 1 meter long 40-50mm waste pipe, and 60cm by the end of each drill two holes added, thereby per insert a rod can be placed on the 16-20mm cable pipes. To the cable pipes then the wires are befestight and tense.
This support tube can be simply as a circular spotlight by tube clamp on the mast be fixed.
The advantage of the antenna is its unobtrusive and that it does not require a downward course, but only to the horizontal. So they can be easily mounted on a rotor in a tree crown, thus saving themselves an expensive 10-20m Aluminium sliding boom.
The complete structure weighs about 3kg, so that it applies also to stable fiberglass poles place (without rotor).
Let's see what we can do. This project will again tackle ...
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