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Re: So what antenna is better ?



John ,
Not all QFH antennas have thier maximum gain at Zenith.

Look at 1 Wavelength per side 1 Turn.

Art, KC6UQH


----- Original Message ----- 
From: "John B. Stephensen" <kd6ozh@verizon.net>
To: "Andrew Rich" <vk4tec@tech-software.net>; "Amsat-Bb" 
<amsat-bb@amsat.org>
Sent: Thursday, August 18, 2005 10:08 AM
Subject: Re: [amsat-bb] So what antenna is better ?


> If you're using it for LEO satellites, the Lindenblad is better as it has
> gain near the horizon and the pattern there is circularly polarized. I 
> built
> one for 10 meters in 1993 and it was very large, but worked well.
>
> The Eggbeater (without a ground plane) is horizontally polarized near the
> horizon and circularly polarized at the zenith. I suspect that it is worse
> than a vertical antenna for LEOs as there is slightly less gain near the
> horizon. If a ground plane is used, the pattern points up and is not very
> useful for LEOs.
>
> The QFH is CP but the pattern points towards the zenith.
>
> A vertical is second best for LEOs. The only disadvantage is fading if the
> satellite is linearly polarized.
>
> 73,
>
> John
> KD6OZH
>
> ----- Original Message -----
> From: "Andrew Rich" <vk4tec@tech-software.net>
> To: "Amsat-Bb" <amsat-bb@amsat.org>
> Sent: Thursday, August 18, 2005 11:09 UTC
> Subject: [amsat-bb] So what antenna is better ?
>
>
>> Lindenblad
>> Quadrifilar helix
>> Eggbeater
>> ----
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> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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