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Old Apr 09, 2011, 08:00 AM
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Switzerland, LU, Buchrain
Joined Aug 2006
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Yippee!
5.8Ghz circular polarized omnidirectional range test sensation

Hi all,

I just wanted to share this. We did a short range test trying to find the limits of the following 5.8ghz setup:

- Custom 200mW tx
- Stock RC 305 reciver
- custom Cloverleaf 5.8Ghz omnidirectional cicular polarized antenna on tx
- custom Skew Planar Wheel 5.8Ghz omnidirectional cicular polarized antenna on rx

We flew out 4.5Km and returned. No special events so far. We now will try to go out even further as there was still no visible degreation in video quality and report back. The 4.5Km were without any noticeable events, clear video, no issues.

Edit: We flew again, this time we went 6 Km out! At this point we had to return because the video started to slightly snow at around 5Km, getting to a ponit at 6Km where we found it adviseable to return. So it seems that one can fly out with this setup to 5Km without much concern!

The transmitter is the one presented in this thread:

http://www.rcgroups.com/forums/showthread.php?t=1404925

However, it uses the same HF module as the stock tx. We haven't tested yet if the stock tx would be worse range wise. We may will test this later.

The custom tx, the cloverleaf and skew planar wheel antennas were made by myself.

Omnidirectional circular polarized antennas rule

Markus
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Last edited by markus123456; Apr 09, 2011 at 10:36 AM. Reason: New flight out to 6Km
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Old Apr 09, 2011, 01:44 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
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Quote:
Originally Posted by markus123456 View Post
Omnidirectional circular polarized antennas rule

Markus
That's an understatement.

CP is the way of the future for FPV. No two ways about it. Anyone who doesn't think that has likely never tried it.

-Alex
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Old Apr 09, 2011, 01:50 PM
Kiwi in Germany
whakahere's Avatar
Germany
Joined Jun 2010
2,255 Posts
I so need to get a LRS and test the stock TX. Looking forward to your findings markus. Looks like I am not so upset that I went with 5.8 after all. 6km here in Germany is great as going further you are always over towns.

I can't believe the different CP antennas work. Alex you changed the way I enjoy FPV with these.
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Old Apr 09, 2011, 04:27 PM
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Canada, ON, Toronto
Joined Mar 2011
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Only if someone could do the same test with the stock 200mW tx so we can see how much of a difference the custom tx makes.

btw Markus, was this test done in a RF busy area? Were there any tall buildings between you and the plane at 5km to prove CP and 5.8Ghz really work? thanks!
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Old Apr 09, 2011, 05:29 PM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by spol View Post
Only if someone could do the same test with the stock 200mW tx so we can see how much of a difference the custom tx makes.

btw Markus, was this test done in a RF busy area? Were there any tall buildings between you and the plane at 5km to prove CP and 5.8Ghz really work? thanks!
This particular test was made more in a country side area. There IS civilisation around too (as in most parts of Switzerland) but it was not really a city. We had to go there because of regulations at the usual flying field which would not have allowed to do this kind of tests. We usually fly from an air base and there some rigid restrictions are in place.

Regarding the tx, the only difference is the power feed of the transtmitter module the HF module is the same as the one used in the stock tx.
Obviousely good filtering can lead to more range if there is less noise disturbing the image when reaching the limits. I think though that if it would not have been the same, the difference might only be in the last kilometer flown.

There are IMHO two magic factors here. First and most importantly the antennas, secondly the exceptionally good reciver with its outstanding -90dB sensitivity.

So if anyone wants to reproduce this, get yourself a pair of those CP antennas. I'm willing to make some so as people can reproduce my experience. Intersted parties shall send me PM.

Markus
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Old Apr 11, 2011, 11:04 AM
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Switzerland, LU, Buchrain
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The CP antennas rule

Hi all,

I'm getting messages from people interested in my transmitter thining it was the transmitter who is responsible for this exceptional flight. I'd like state that similar range can be reached with the STOCK transmitter. The magic is in the circularely polarized antennas. I'm sorry if my information given was misunderstood.

Markus
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Old Apr 11, 2011, 11:15 AM
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What reciever did you use markus?
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Old Apr 11, 2011, 11:20 AM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by mitsudriver274 View Post
What reciever did you use markus?
The stock reciver, RC 305 as it's available on many places.

Markus
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Old Apr 11, 2011, 11:24 AM
ysb
use the force..or a quadcopter
ysb's Avatar
quebec
Joined Dec 2010
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the best is not the contrary ?

custom Cloverleaf 5.8Ghz omnidirectional cicular polarized antenna on RX (receiver) instead of tx
- custom Skew Planar Wheel 5.8Ghz omnidirectional cicular polarized antenna on TX (transmetter) instead of rx
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Last edited by ysb; Apr 11, 2011 at 11:31 AM.
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Old Apr 11, 2011, 11:44 AM
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Amherst, VA
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That will work fine. The skew wheel and cloverleaf are more or less interchangeable. however the Skew wheel has better multipath rejection and the cloverleaf just seems to do a little better as a TX antenna than the skew wheel.

-Alex
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Old Apr 11, 2011, 01:26 PM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by ysb View Post
the best is not the contrary ?

custom Cloverleaf 5.8Ghz omnidirectional cicular polarized antenna on RX (receiver) instead of tx
- custom Skew Planar Wheel 5.8Ghz omnidirectional cicular polarized antenna on TX (transmetter) instead of rx
I don't understand what you mean. I wrote:

- custom Cloverleaf 5.8Ghz omnidirectional cicular polarized antenna on tx
- custom Skew Planar Wheel 5.8Ghz omnidirectional cicular polarized antenna on rx

That said, the cloverleaf is a superior antenna to TRANSMIT, where as the skew planar wheel is really good on reciveing.

Note, english is not my native language, maybe that's why. Could you clarify what your point is?

Markus
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Old Apr 11, 2011, 01:47 PM
ysb
use the force..or a quadcopter
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sorry .. in my mind, I thought it was the opposite ..
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Old Apr 11, 2011, 01:51 PM
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Miami, FL
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Crazy you got so far, I cant even get 1/5 that distance with my CP antennas.
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Old Apr 11, 2011, 01:57 PM
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Switzerland, LU, Buchrain
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Originally Posted by airbagit13 View Post
Crazy you got so far, I cant even get 1/5 that distance with my CP antennas.
What frequency? Did you make them yourself?

Are you using this tx/rx?
http://www.himodel.com/electric/FPV_...ng_System.html

(note, this set is available in many places, above store is only for reference, I do not endorse it specially nore am I in any ways related)

If in doubth about your antennas, I could make you a pair. I'm sure you can duplicate my experience.

Markus
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Old Apr 11, 2011, 02:07 PM
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Amherst, VA
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Quote:
Originally Posted by airbagit13 View Post
Crazy you got so far, I cant even get 1/5 that distance with my CP antennas.
It's all about the RF environment. I did 2.5km on mine on 1.3GHz, no problems. 900MHz gets hammered by cell phones and towers which can significantly reduce your range.

-Alex
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