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Topband: Phasing Flag antennas?

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Subject: Topband: Phasing Flag antennas?
From: (Tom Rauch)
Date: Sat, 20 Nov 1999 20:24:44 -0500
I think I sent my response to the wrong address. I'll try again.

> In the broadside configuration, yes, the azimuth lobe will be sharpened
> significantly with in-phase feeding if the spacing is at least 1/4 wave.

> In the end-fire configuration, very little sharpening of the azimuth
> pattern will occur. =====

Not true.

> What kind of pattern can I expect?

> =====

> The azimuth pattern of a single Flag is about 145 degrees wide at its -3
> dB points on both 540 and 1830 kHz.  
> With 150-foot broadside spacing, it's 140 degrees wide at 540 kHz and 103
> degrees wide at 1830 kHz.

With only 100 feet end-fire spacing and 180 degree shift, the -3dB 
beamwidth is less than 80 degrees with end-fire spacing of only 
100 feet on 1.8 MHz.

> In the end-fire configuration, no directional control is available by
> varying the phasing. =====

Not true, the nulls can be moved anywhere on the azimuth. The 
main response can be moved also, as much as directly off the 
sides. Of course it splits into multiple lobes.

End-fire spacing always provides a sharper lobe than broadside in 
small arrays, and especially in arrays using elements that already 
have some side suppression in each element.

73, Tom W8JI

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