CP antenna vs antenna with same Co and Cross polarizations

[a.mal]

Hi Everyone,

Consider having a RHCP antenna as a transmitter (placed in xy plane and transmitting toward z-direction). If I have an antenna with same level of Co and Cross polarization (cross shape dipole placed in xy plane oriented along -z direction), how much power I am going to receive?

Thanks

 

[vfone]

The question should be: What is the path loss DIFFERENCE compared to the situation when I use at the receiver side also a RHCP antenna (which gives the best match to the TX antenna)?
The answer is: At least 3dB higher path loss between TX and RX.

 

[D.A.(Tony)Stewart]

look up Friis Loss calculator

 

[a.mal]

The question should be: What is the path loss DIFFERENCE compared to the situation when I use at the receiver side also a RHCP antenna (which gives the best match to the TX antenna)?
The answer is: At least 3dB higher path loss between TX and RX.

Thanks for your reply.

So, I don't understand why the path-loss should increase by 3dB since I can catch all the x and y polarizations with my dipoles.

 

[hagster]

Thanks for your reply.

So, I don't understand why the path-loss should increase by 3dB since I can catch all the x and y polarizations with my dipoles.

You are only collecting ALL the signal (coherently)if you phase the 2 dipoles correctly as the signal will have a 90 degree phase difference between each antenna. I you do that you have just built a CP antenna. There are lots of cross dipole 'turnstyle' antenna that are configure in this way.