QFH:
Introducción
Adaptación
Simulaciones
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Plano tierra
Relacionado:
Helicoidal simple
It might LOOK strange.......But does it EVER receive good pictures.
Made out of 5 mtrs of 8mm microbore central heating copper pipe.....8 X 90deg 8mm elbows......5 amp mains junction box (at top).......a length of 40mm waste water pipe, with one "stop end cap" (to bolt the 5 amp junction box at the top to). Feed coaxial cable feeds inside the mast.
One "loop" is slightly long at resonent frequency (137.5 MHz) and is therefore "inductive".....and one slightly shorter than resonent frequency, and therefore "capacitive".
Not every easy to take a picture of.......but the cross elements at top and bottom ensure signal is not lost if satellite passes directly overhead.
IMPORTANT NOTE: All copper has been painted matt black so that I can tell the neighbours that it is a BIRD RESTING PLACE. Then they will think that I am a great guy to have as a neighbour (instead of complaining to the Parish Council).
73,
Nev, G3LMO nevcooper@g3lmo.com
(c) John Coppens ON6JC/LW3HAZ | correo |