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Old Apr 02, 2011, 07:48 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,453 Posts
New Product
Turnstile UHF RX antenna for your LRS

If you own a flying wing, you know what a pain it is to find a place to mount your LRS antenna upright for proper polarization. Now you don't have to. The turnstile antenna is a dual polarized antenna that is designed to lay flat where it is convenient.

I designed this antenna specifically for flying wing pilots, but it works just fine for any airplane. Mount the antenna flat on the bottom of the wing. The radiation pattern has no holes in it and is almost a perfect sphere. I use this with my Dragonlink, but it will work with any UHF radio system. While I tend to use it as an RX antenna, it also works as a TX antenna.

Admittedly, I need to give credit to MR. RC-CAM for this one. He challenged some of us on the RC-CAM forum to figure it out and build one.... So I did It uses the reactive impedances to match a proper 50 ohm load hence the mist matched leg lengths.

You can buy one from Video Aerial Systems

Or of course, you can build your own. But I won't force you guys to figure out the math. Instead, here's a video to show you how it's done:

Build IBCrazy's 433MHz Turnstile antenna for FPV (6 min 5 sec)


Why am I giving away the details? Because I want to, that's why I encourage you who have fair soldering skill to try one.

-Alex
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Old Apr 02, 2011, 07:53 PM
Thou who know not
Po73's Avatar
USA, MI, Mason
Joined Jul 2010
936 Posts
Have you done a range test in the air yet? I've been contemplating using these for both video and rc on the flat side on a raidian.
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Old Apr 09, 2011, 11:12 AM
Post # 20 million
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Thanks for offering this design, Alex.





Cheers, Kev.
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Old May 21, 2011, 06:38 AM
Post # 20 million
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Joined Aug 2009
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And one mounted on my bros quad.




Cheers, Kev.
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Old May 21, 2011, 09:43 AM
Air Crash Expert
sawman's Avatar
Louisiana
Joined Oct 2005
1,196 Posts
Alex,
I have copper foil with adhesive backing. It is 3/4 inch in width. Guess you know where I'm going with this.
What effect does the width have on the element lengths ? Also curious about what kind of gain to expect.
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Old May 22, 2011, 07:27 AM
Honey Badger
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United States, FL
Joined Oct 2005
1,814 Posts
Will putting a piece of ny-rod over the elements change anything?
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Old May 22, 2011, 08:07 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,453 Posts
Quote:
Originally Posted by sawman View Post
Alex,
I have copper foil with adhesive backing. It is 3/4 inch in width. Guess you know where I'm going with this.
What effect does the width have on the element lengths ? Also curious about what kind of gain to expect.
Bad idea. The element thickness is critical. The lengths are actually quite loose but you must use 20-24AWG wire.

-Alex
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Old May 23, 2011, 05:44 AM
Registered User
FRANCE
Joined Oct 2005
42 Posts
Hello !

I can install the antenna along the aluminum arms of a MK?
I think about wiring the metallics arms with battery ground.Good idea or it's useless?
Thanks
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Old May 23, 2011, 07:30 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,453 Posts
I would not do that. The aluminum will mutually couple with the antenna similar to how a Yagi antenna works. However, in the case of the booms, it will most certainly be a bad thing...

-Alex
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Old May 23, 2011, 09:21 AM
Air Crash Expert
sawman's Avatar
Louisiana
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Quote:
Originally Posted by IBCrazy View Post
Bad idea. The element thickness is critical. The lengths are actually quite loose but you must use 20-24AWG wire.

-Alex
Thanks .
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Old May 23, 2011, 11:32 AM
Registered User
FRANCE
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Quote:
Originally Posted by IBCrazy View Post
I would not do that. The aluminum will mutually couple with the antenna similar to how a Yagi antenna works. However, in the case of the booms, it will most certainly be a bad thing...

-Alex
Thanks Alex !

Ok ,it's not recommended to use turnstile antenna on quadrocopter with metallic frame ,stock antenna is preferable?
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Old May 23, 2011, 12:28 PM
Engineer for Christ
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Amherst, VA
Joined Jun 2006
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The stock antenna won't do any better on a metal frame. The aluminum will react just the same. This is a case where 2.4GHz would be the best choice for control.

-Alex
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Old May 23, 2011, 12:59 PM
RC pilot by soul
Israel
Joined Apr 2005
2,494 Posts
Alex,

Will 18 AWG wire off a burnt computer PSU work well ?
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Old May 23, 2011, 02:36 PM
Engineer for Christ
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Amherst, VA
Joined Jun 2006
10,453 Posts
It would do ok. It would be a little out of circularity, but you'll be ok for most purposes.

-Alex
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Old May 23, 2011, 02:39 PM
RC pilot by soul
Israel
Joined Apr 2005
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Quote:
Originally Posted by IBCrazy View Post
It would be a little out of circularity
What does that mean in simple terms ?
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