I done some test at scale ( 40 feet tower with a 5 ele. 28 Mhz
monobander with parasits elements grounded to the boom ). The results
was expectacular on 40 meters ( compared with my 2 ele monobander at 60
feet hight, all ways the monoband was better but the I broke easy
severals pile-up's with the shut-fed tower.
Now, in orde to have a single tower for al bands, I am working to set up
a 90 feet self-supported tower ( 1.5 meter x 1.5 meter in the base and
0.55 meter x 0.55 meter at top ) and try to use this on 80 an 160
meters. Up this tower I will put a 2 inc. diameter mast ( 1/4 inc. wall
) of steel to support next to top of the tower a KT34XA-HD and 10 feet
up a 2 ele. mon. for 40 meter.
I read in a book, a formula to calculate the equivalent electrical
length of this shut-fed tower (using basically the physical hight of the
tower and the surface of the top hat) , but the elements both antennas,
the KT34XA and 402-CD ) are isulated's from the boom. How affect that
the elements are isulated of the boom to caltulate the hat surface ?.
Wich antenna I can use to calculate the equivalent surface, the nect of
the tower or the antenna at top of the mast ?.
I will aprecciatte so much any comment or experience .
73 es DX.
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