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How would a collinear dipole behave ?

Externet

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Hello.

Collinear antennas as each of both dipole arms; what behavior/performance to expect ?

1631639159125.png


Visualize feed point connected at centre. Image borrowed from the web, mirrored.

Usually placed vertical; they present high gain as a single collinear. Placed horizontally as dipole arms, do the coils behave as 'multiband traps' or would it be a 'double' collineal ?
 

SunnySkyguy

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Each linear section should add to the previous if there is a 180 deg phase shift or wire swap or 180 deg orientation swap like you planned. If phases are coherent then the aperture reduces and gain increases if no losses. But ganging two in parallel reduces impedance in half with expected return loss.
 

vfone

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The antenna in the picture is a collinear array using half-wavelength monopole elements and phasing coils between elements to get the necessary phase shift.
This is the simplest configuration for a collinear antenna, but is the least efficient due to losses in the coils.
 

SunnySkyguy

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The traps are parallel LC tuned to high impedance between short and longer wavelengths. Each pole would need a bifilar connection to reverse phases with a delay line commonly found on Uda/Yagi antennae
 

Externet

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Thanks, gentlemen. Would this be more convenient than with the coils, perhaps extended to about 4 blue stubs each arm ?

1631981740278.png


(Image borrowed from the web)
 

vfone

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Theoretically should be better using stubs, because they don't have such losses as coils.
 

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