CL + SP question

[guy1a]

1st. i am sorry if it is a common knowledge .. i couldn't find it ...

2nd. what is the reason for this to be a pair ?
also why the CL should be on the TX side and the SP on the RX side ?

why not SP on both sides ?

thank you.

[IBCrazy]

They are sold as a pair because you need a cp antenna on both ends for it to work properly.

The reason the CL is used as a TX antenna has many reasons, but mainly because it simply works better. In a perfect world, the SPW would be better, however the way reflections work, the cloverleaf dominates. If you look at the rejection pattern, there are three narrow defined lobes. These lobes have a 10 db drop at the tips an 18 db at the centers. This causese the reflected signal to vary wildly in amplitude and thus it gets knocked out by the processor on the VRX. However, in times of attempting to run around objects such as trees, the signal reverses and is strong enough to be accepted as valid as the forward signal is now reversed. While you do get some scrambling, the video is still flyable and stable.

-Alex

[guy1a]

Ok.

Thank you for the answer.

So cl and spw will be better then cl and bi quad ?

[IBCrazy]

*sigh* - Better is a relative term. If you are going for long range, no. However mixing a CL and a Biquad is sub optimal.

If you want range, use a vee/Biquad or a CL/Crosshair combination. If you want omni directional, then go with a CL/SPW combination.

-Alex

[guy1a]

i am sorry

i have cl on the plane and this on the ground

http://fpvlab.com/forums/showthread....e-Quad-antenna

not bi-quad.
i get 1.5 kilometers of flyable video with 500 miliwatt tx.
i can get more but i was afraid.

i think my antennas are not very good.
i will check them with the swr meter and try to make smaller gaps.

thank you.