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New yagi 3 element. 6-40 metres

  3 elementi 6-40

 

3 ELEMENT YAGI (6-40 METRES)

 

 

 

The above diagram shows how a three element yagi can also perform with two full-size elements on 30-40 mtrs. The two longest elements are 21,5 metres long, and when operating in the range 6-20 mtrs the antenna is performing as a normal full-size three element yagi.

 

When 30-40 mtrs are selected the middle element will be fully retracted and the feeding line will be switched to the driven-element for these bands (one of the longest element). The CPU provides full automatic switching from the 6-20 mtr driven-element to the 30-40 mtr driven-element.

 

In order to have one of the 21,5 mt element performing as a driven-element, the Motor Unit is equipped with a balun and a relay.

 

When one of the longest element has to perform as a passive element (reflector or director)the relay short-circuits the two beryllium-copper halves. When it has to perform as a driven-element the relay opens the short-circuit and connects the two beryllium copper halves to the balun. Switching is performed automatically by the CPU (Antenna Controller).

 

Apart the advantages described above, this boom-mounted electronic switching-system offers the advandage of feeding the antenna by a sigle coax-cable.

 

This unique and extremely reliable switching-system allows the antenna to perform as effectively as following full-size monobanders:

 

2 elements on 30-40 mtrs, 5 mt boom;

3 elements on 10-20 mtrs, 5 mt boom;

4 elements on 6 mtrs on a 4 mtrs boom ( with 2 optional passive elements).

 

Total weight: 60 kg.

 

Our switching system solves the problem involved by the unsufficient spacing on the 30-40 mtr bands. When 30-40 mtrs are selected, the switching system "shifts" the driven-element from the center to one end of the boom. Without this system the perfomances on 30-40 mtrs would be unacceptable because of the 2,6 metres between the two elements.