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Old Feb 17, 2011, 11:33 PM
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Have fun skiing Alex! I need to hit the slopes again too before it all melts =)
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Old Feb 18, 2011, 07:12 PM
matyou is offline
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Hi all,

Well after having a bunch of fun making the Vee I decided to start making a cloverleaf antenna. I used 0.027 copper magnet wire just to try it out before I get some .035 mig wire. I did everything to the best of my ability and understanding of the instructions but Im not getting much performance out of the antenna when used along with a rubber ducky for the VRX. Below are some pictures I took to see if anyone can help me out.

Thanks



Last edited by matyou; Feb 18, 2011 at 07:26 PM.
Old Feb 18, 2011, 08:17 PM
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If I understand correctly, you need a circular polarized antenna on both sides; tx and rx, to get good performance. Rubber ducky is linearly polarized.
Old Feb 18, 2011, 08:24 PM
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With a linear and a circular antenna you lose about 3db but still should work. I have a feeling that I did something wrong.
Old Feb 18, 2011, 08:26 PM
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dbi Mismatch Basics


V to V = 0dbi
V to H = -26dbi
i.e. dbi can change from 0 to -26dbi in a 90 degree bank

CP to L (V or H) = -3dbi
Stays -3dbi when the antennae change angles

CP to CP = 0dbi
Stays 0dbi when the antennae change angles

RHCP to LHCP = -26dbi
Stays -26dbi when the antennae change angles

So one should see a marked improvement in multipath rejection and consistancy of video in a turn but not longer range with a CP and L combo.

Jeff
Old Feb 18, 2011, 08:57 PM
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Jeff,
Have you tried this antenna yet? I wonder why I cant get any good performance from it? Does it look right?

Matt
Old Feb 18, 2011, 09:03 PM
BloomingtonFPV is offline
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KC9TPL- Get Legit
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Quote:
Originally Posted by workshop View Post
V to V = 0dbi
V to H = -26dbi
i.e. dbi can change from 0 to -26dbi in a 90 degree bank

CP to L (V or H) = -3dbi
Stays -3dbi when the antennae change angles

CP to CP = 0dbi
Stays 0dbi when the antennae change angles

RHCP to LHCP = -26dbi
Stays -26dbi when the antennae change angles

So one should see a marked improvement in multipath rejection and consistancy of video in a turn but not longer range with a CP and L combo.

Jeff

Doesn't a -3dbi change translate roughly into losing half your distance (range)? If so, this sounds like a lot. I'm trying to decide if I can mix CP and inverted Vs on different planes but have the same vertical patch on my rx.
Old Feb 18, 2011, 09:33 PM
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I've tried the antenna on the bench and it burrows through walls! Simply amazing...

I've used CP on the RX side for years and it changed the hobby. -3bdi down still means two miles (w/ standard rubber duck on the TX) but with a consistant image of which I can depend.

NOW... with CP on both sides, I am really excited...

Jeff
Old Feb 18, 2011, 10:22 PM
IBCrazy is offline
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Quote:
Originally Posted by matyou View Post
Hi all,

Well after having a bunch of fun making the Vee I decided to start making a cloverleaf antenna. I used 0.027 copper magnet wire just to try it out before I get some .035 mig wire. I did everything to the best of my ability and understanding of the instructions but Im not getting much performance out of the antenna when used along with a rubber ducky for the VRX. Below are some pictures I took to see if anyone can help me out.

Thanks



I can see many problems:
1. Your angles are not correct. You need to come off that center conductor at 45 degrees with each element.

2. You are using RG174 coaxial cable. Chances are you heated it up too much and the center element shifted internally. RG174 has poor heat characteristics.

3. We have no idea where you are mounting this. Location makes a difference.

4. You need a CP antenna on the RX side too. Try a helix or another cloverleaf. Multipath with omnis is a killer. Believe it or not, when receiving with a linear omni antenna, a CP antenna makes the multipath problem worse!

5. The thin wire will distort very easily in the wind causing sporadic power level changes. VTX units do not adapt well to this.

-Alex
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Old Feb 18, 2011, 10:23 PM
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Quote:
Originally Posted by workshop View Post
I've tried the antenna on the bench and it burrows through walls! Simply amazing...

I've used CP on the RX side for years and it changed the hobby. -3bdi down still means two miles (w/ standard rubber duck on the TX) but with a consistant image of which I can depend.

NOW... with CP on both sides, I am really excited...

Jeff
And I've got some new stuff coming out soon. Wait until you try it

-Alex
RCG Plus Member
Old Feb 19, 2011, 12:42 AM
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Quote:
Originally Posted by IBCrazy View Post
And I've got some new stuff coming out soon. Wait until you try it

-Alex
Wow already?! Glad I haven't started building this one yet
Old Feb 19, 2011, 04:02 AM
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I thought that the original had 4 elements, but now I see 3. Would a 4 be better?
Old Feb 19, 2011, 09:11 AM
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Quote:
Originally Posted by volto View Post
Wow already?! Glad I haven't started building this one yet
Build this one. It is the center piece of it all. All of my other antennas are Rx antennas that revolve around this one.

-Alex
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Old Feb 19, 2011, 09:13 AM
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Quote:
Originally Posted by Flypoppa View Post
I thought that the original had 4 elements, but now I see 3. Would a 4 be better?
They are different antennas. The 4 lobe is the skew-planar-wheel. The 3 lobe is the cloverleaf. The cloverleaf has higher gain, but less reverse polarity rejection.

-Alex
RCG Plus Member
Old Feb 19, 2011, 09:36 AM
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Question:
What's type of mig wire is better to use? Steel, carbon steel, high or low nickel content, aluminum? Also, did you run into any problems soldering the wire?


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