what is the RHCP and LHCP

[ali101]

Hi
This is a bit of a noob question but I was just wondering what the difference is ,and generally what are they, between right-hand circular polarized(RHCP) and left-hand circular polarized(LHCP)
Thanks

[Coyote]

The difference between them is the one transmits in a clockwise circular pattern, the other in an anticlockwise.

The reason for it originally is that with a linear antenna that you get as standard you get huge losses if the antennas do not mirror each others orientation. In a plane or multicopter a lot of the time the craft is tilted or pitched so the antenna is not matching, this then reduces range.

With the circular antennas this is no longer a problem because the pattern is circular, so no matter what angle its still a circle so no losses.

Another advantage is that linear antennas will receive bounced signals from reflective objects including the ground and display them in the form of interference, its called multipath interference. Circular antennas reject this multipath brilliantly because when the signal reflects it changes the clockwise pattern to anti clockwise, so the clockwise receiver antenna hardly sees it but receives the correct signal just fine.

Performance wise there is no difference between left and right handed, they do both the same thing in exactly the same way. You get good separation between right and left so it also lends itself to multiple people flying together, now not only do they have the channel difference between them but the added rejection that linear doesn't give you.

The down size is they are more draggy in the air than linear, linear tend to have a touch more gain so more ultimate range, but linear for me is only ever worth using on 1.2 or 2.4GHz only.

[ali101]

so on a reciever can I use a RHCP or LHCP antenna or is it on a certain receiver you can only use a certain antenna, either RCHP or LHCP.

[Coyote]

As long as the antenna on your receiver is the same polarization as the one on the craft you can use either.

So

LHCP antenna on reciever --- LHCP must be used of the plane
RHCP on receiver --- RHCP must be used on the plane

[ali101]

ok thanks a lot guys for all the help