[TowerTalk] Fwd: Dipole gain?

[Joe Subich, W4TV]

Any horizontal antenna will have a direction (angle above
horizontal) with higher power density due to the combination
of direct rays and rays reflected from the ground.

The turnstile, if properly fed, will have uniform angular
radiation in the horizontal plane.  Vertical "take off" angle
will depend on height above ground and the "circular" radiation
directly up will depend again on height above ground and the
ground constants.

73,

    ... Joe, W4TV


On 2014-12-09 5:45 PM, Hans Hammarquist via TowerTalk wrote:
> Hi Jim,
>
>
> The next question then is; Do two horizontal, crossed dipoles, feed 90° out of phase have an even power distribution across the hemisphere, horizontal across the horizon and circular above and below or is there a direction with a higher power density?
>
>
> Hans - N2JFS
>
>
>
> -----Original Message-----
> From: Jim Lux <jimlux at earthlink.net>
> To: Hans Hammarquist <hanslg at aol.com>
> Sent: Mon, Dec 8, 2014 9:58 pm
> Subject: Re: [TowerTalk] Dipole gain?
>
>
> On 12/8/14, 6:45 PM, Hans Hammarquist via TowerTalk wrote:
> That way you should
>> subtract 3 dB to get a comparison between an antenna gain give over
>> the isotropic. I was also told that two crossed dipoles were as close
>> to an isotropic radiator you could get.
>
> Not really. two crossed dipoles fed in phase is the same as a dipole at
> 45 degrees.  two crossed dipoles fed 90 degrees out of phase is
> circularly polarized in the direction normal to the plane containing the
> dipoles.  Other arrangements of dipoles (e.g. a Lindenblad or a
> turnstile) may have better circularity in some directions.
>
>
>
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