Re: [Paparazzi-devel] circular polarized antenna hype

[Marc Schwarzbach]

Hi Tilman,

the basic principle of loss of signal strength when two linear antennas are out 
of phase applys to XBee, too, of course. So you could avoid that by spending a 
constant loss of 3dB when using a circular polarized antenna on one side.

In my oppinion it makes sense when using a higher gain circular on the ground 
(patch or helix) and a standard omni on the plane.
I´m a little sceptical with all the hype around cloverleaves and so on... Also 
look fragile when used on the plane :-)

I have no problems with 2.4GHz Xbees with standard wire antennas up to 1km.

Do you have problems with your connection?

Cheers

Marc





-------- Original-Nachricht --------
> Datum: Mon, 23 Jul 2012 14:30:56 +0100
> Von: Tilman Baumann <address@hidden>
> An: address@hidden
> Betreff: [Paparazzi-devel] circular polarized antenna hype

> What is up with those circular polarized antennas that are all the rage 
> in the FPW world right now?
> http://www.fpvuk.org/equipment/circular-polarized-antennas/
> 
> The problems they are trying to avoid should be present in telemetry as 
> well. Which is loss of signal when antennas are out of phase. (Vertical 
> vs. Horizontal)
> 
> I wonder, would it make sense to hook one of those cloverleaves to a 
> XBee? How does the fact that we use bidirectional signals the efficiency 
> of those?
> Has anyone tried? Should trials be made?
> Do I understand correctly that only one side should be circular 
> polarized? Or should have receiver and transmitter the same antenna?
> 
> I thought I bring that up since it has not been discussed here as far as 
> I know. I'm curious in your opinions.
> 
>   Tilman
> 
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