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Old Feb 27, 2011, 05:59 AM
Happy FPV pilot
lucianozan's Avatar
Italy
Joined Feb 2009
148 Posts
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Originally Posted by lucianozan View Post
Next tests will be a new Cloverleaf mounted at 90 under the FPV T-REX450 boom. With the standard whip in the same position I get a lot of disturbance when the heli is flying low facing the ground station ...if I land a bit far sometimes I even loose the video signal.
Tested today the magic Cloverleaf on my T-REX450 FPV.

It's great! I've no video but, believe me, it works really well! very few disturbance during flight in all directions and even when the heli is flying low, nose in, the video signal is good. Tried landing far from the ground station and with the heli on the ground I had still a good image and I was able to take off without any problem.

...now I'm building CP antenna for all my models!!

Luciano
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Old Feb 27, 2011, 08:20 AM
HeliAP'er!
Hogster's Avatar
Surrey, UK
Joined Aug 2003
8,214 Posts
Subscribing It looks like this antenna would work very well on my aerial photography setup. At the moment I'm using a 3dBi whip antenna on the VTx (Airwave 661 5.8GHz 25mW), and an 8dBi linear-polarised patch antenna on the VRx (Airwave 682 5.8GHz).

At the moment I'm getting quite a lot of (what I've been told might be) multi-path interference that's causing my LCD monitor to go blank temporarily. This is the raw video which I was able to capture:

Airwave 5.8GHz video link test (3 min 18 sec)


I need to do another test with everything in exactly the same position, but I don't think the LCD would have coped very well with that interference

Unlike FPV, my main use for this platform is hovering 50-100m from a subject that is being photographed ... I assumed that LP antennas wouldn't cause too many problems, but I gather that LP antennas are more susceptible to multi-path interference than CP antennas, hence my interest in this thread!

Thanks for all the incredible info that's being shared here!


David
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Old Feb 27, 2011, 09:48 AM
HeliAP'er!
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Surrey, UK
Joined Aug 2003
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Quote:
Originally Posted by IBCrazy View Post
I find the cloverleaf (3 blade) is a bit easier at 5.8GHz. It performs just as well as the skew-planar wheel in my tests. You need to compensate for the added length given from the coaxial cable sticking out of the connector by shortening the lobes a bit.

-Alex
Hi Alex

Can you elaborate on how much shorter the lobes need to be? If the cloverleaf performs just as well as the SPW, I'll probably try building one of those ... 3/4 of the parts to make accurately!

Many thanks for all your support / help in this thread!


David
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Old Feb 28, 2011, 07:15 AM
Registered User
Joined May 2010
237 Posts
Hello,
just made a SP antenna. Does that look right?


and I have a question:
I have FatShark 100mW 2.4GHz transmitter witch has a wire instead of antenna. Can I just solder the coaxial with SP instead of that wire?


Thanks
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Old Feb 28, 2011, 09:18 AM
O <- this a ground loop
Japan
Joined Nov 2010
514 Posts
Quote:
Originally Posted by aSa2 View Post
Hello,
just made a SP antenna. Does that look right?


and I have a question:
I have FatShark 100mW 2.4GHz transmitter witch has a wire instead of antenna. Can I just solder the coaxial with SP instead of that wire?


Thanks
asa2,

it looks like you know what you are doing.

Just be careful that you use a hot iron and don't push down on the tracks around the RF module too hard.
They can be a bit fragile.

And remember to visually inspect for shorts before you power it up.

good luck

Ren
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Old Feb 28, 2011, 02:58 PM
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Originally Posted by devfor View Post
asa2,

it looks like you know what you are doing.

Just be careful that you use a hot iron and don't push down on the tracks around the RF module too hard.
They can be a bit fragile.

And remember to visually inspect for shorts before you power it up.

good luck

Ren
Thanks
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Old Feb 28, 2011, 04:09 PM
Whats the wrst that can happn?
AdamChicago's Avatar
Chicago, IL USA
Joined May 2010
2,657 Posts
Alex, I have an off topic question for you since you're the RF guru...and I probably don't have enough info for you to make a solid conclusion, but just wanted your opinioin.

I discovered an awesome place to fly, BUT about 300 feet from the take off location facing in the opposite direction (south) is a huge approx 25ft diameter dish pointed roughly at a 45 degree angle up towards the sky (behind the Lucent office in Illinois), which I do not know if it's transmitting or receiving. Is this a potential concern for RF interference with a 433 UHF Rx and 910 VTx FPV setup even if I be will 300+ feet away and will be flying behind and away from it?
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Old Feb 28, 2011, 05:26 PM
HeliAP'er!
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Surrey, UK
Joined Aug 2003
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Here's my attempt at a SPW for 5.8GHz - took me a good hour of slow work, but I'm quite pleased with it I'm not happy that the upper arms don't perfectly overlap the lower ones though ... challenge for my next one!





Thanks for the detailed instructions! Now to test it!


David
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Old Feb 28, 2011, 07:03 PM
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Hugeone's Avatar
Canada,Quebec
Joined Jan 2005
2,035 Posts
Quote:
I'm not happy that the upper arms don't perfectly overlap the lower ones though ...
Hi David!

Your SPW look awesome. The angle between the two quater wave lenght is about 100 degrees, therefore they cannot overlap the lower ones. Alex might give a better answer....

-Hugo (from TrueRC....)
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Old Mar 01, 2011, 07:49 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
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Quote:
Originally Posted by Hogster View Post
Here's my attempt at a SPW for 5.8GHz - took me a good hour of slow work, but I'm quite pleased with it I'm not happy that the upper arms don't perfectly overlap the lower ones though ... challenge for my next one!





Thanks for the detailed instructions! Now to test it!


David
Hugo is correct. You built that antenna quite well! I am very impressed with the work of you guys! Keep it up

-Alex
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Old Mar 01, 2011, 07:51 AM
Engineer for Christ
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Amherst, VA
Joined Jun 2006
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Quote:
Originally Posted by AdamChicago View Post
Alex, I have an off topic question for you since you're the RF guru...and I probably don't have enough info for you to make a solid conclusion, but just wanted your opinioin.

I discovered an awesome place to fly, BUT about 300 feet from the take off location facing in the opposite direction (south) is a huge approx 25ft diameter dish pointed roughly at a 45 degree angle up towards the sky (behind the Lucent office in Illinois), which I do not know if it's transmitting or receiving. Is this a potential concern for RF interference with a 433 UHF Rx and 910 VTx FPV setup even if I be will 300+ feet away and will be flying behind and away from it?
Just don't fly in front of it's beam. Remember, satellite dishes are not necessarily powerful (despite their large size). What they do is compress a signal into a narrow high intensity beam. It could be a multipathing issue if you were standing right next to it, but at 300 feet away, I wouldn't worry about it.

-Alex
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Old Mar 01, 2011, 07:54 AM
Engineer for Christ
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Amherst, VA
Joined Jun 2006
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Quote:
Originally Posted by aSa2 View Post
Hello,
just made a SP antenna. Does that look right?


and I have a question:
I have FatShark 100mW 2.4GHz transmitter witch has a wire instead of antenna. Can I just solder the coaxial with SP instead of that wire?


Thanks
That looks well built. I would put a small amount of hot glue or liquid electrical tape (or even paint) on the feed point of that antenna to keep it from shorting out. The skew-wheel is fairly wide band, so small amounts of dielectrics such as glue affect the frequency very little.

-Alex
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Old Mar 01, 2011, 08:00 AM
Engineer for Christ
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Amherst, VA
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Originally Posted by bas10an View Post
First, my apology if this has been asked before, but could I benefit from using the skew planar or the cloverleaf on my Spektrum transmitter?
Possibly. It would certainly keep your signal from dropping out when banking. It would also give more consistent signal strength.

-Alex
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Old Mar 01, 2011, 12:51 PM
Whats the wrst that can happn?
AdamChicago's Avatar
Chicago, IL USA
Joined May 2010
2,657 Posts
Thanks Alex!

Quote:
Originally Posted by IBCrazy View Post
Just don't fly in front of it's beam. Remember, satellite dishes are not necessarily powerful (despite their large size). What they do is compress a signal into a narrow high intensity beam. It could be a multipathing issue if you were standing right next to it, but at 300 feet away, I wouldn't worry about it.

-Alex
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Old Mar 07, 2011, 07:11 PM
KC9TPL- Get Legit
BloomingtonFPV's Avatar
USA, IN, Bloomington
Joined Aug 2007
833 Posts
Here is a video of a SkewPlanar antenna that I'm about to solder. However, I'm worried that it might be LH Polarized. I'm trying to make all my antenna RHP. I think my cloverleaf at the end is RHP. Can someone who knows about these things tell me which my antenna are?

http://www.youtube.com/watch?v=O_9wyLqjnOU

Sorry for the crappy video. View in HD to see the detail.
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