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Old Mar 02, 2012, 08:03 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,350 Posts
Quote:
Originally Posted by Ceccoz View Post
Thanks Mashton for the answer I will try to reduce it in the future!

IBcrazy what do you think I have to improve? The shape of the lobes?

Francesco
I think everything is fine on your build. I wouldn't change anything. The cloverleaf is very interesting antenna in both it's workings and tolerance to error. You will do fine with your build. Go fly it and have fun

If you really want to play around with it a bit, lower your return (closure) angles from 90 degrees to 60 degrees. This will change the radiation pattern slightly and help with the long feed gap as it makes the lobes react less. In all actuality, this is actually a slight improvement of the cloverleaf called "The AirScrew", which I never introduced because I didn't feel like creating any confusion.

-Alex
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Old Mar 03, 2012, 01:41 AM
ScratchCrasher
sfakias's Avatar
Greece, Central Macedonia, Thessalonika
Joined Jun 2008
579 Posts
Quote:
Originally Posted by IBCrazy View Post
I think everything is fine on your build. I wouldn't change anything. The cloverleaf is very interesting antenna in both it's workings and tolerance to error. You will do fine with your build. Go fly it and have fun

If you really want to play around with it a bit, lower your return (closure) angles from 90 degrees to 60 degrees. This will change the radiation pattern slightly and help with the long feed gap as it makes the lobes react less. In all actuality, this is actually a slight improvement of the cloverleaf called "The AirScrew", which I never introduced because I didn't feel like creating any confusion.

-Alex
Can you please post a couple of pics of the AirScrew Alex?

Thank you.
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Old Mar 03, 2012, 02:03 AM
Registered User
San Marcos, CA
Joined Aug 2009
2,826 Posts
So I am about to get a pair of these antennas.. Does anyone know the approx range with the ImmersionRC 5.8 600W VideoTX?
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Old Mar 03, 2012, 02:07 AM
um.. yeah, I can make that fly
Carlos230023's Avatar
United Kingdom, Milton Keynes
Joined Jun 2007
3,703 Posts
I've done 2.3km with the immersion setup. Was pretty clear most of the way. Started to waiver at the 2.2km mark. Probibally could have pushed it to 2.5km. The beauty of these antennas is they don't just switch off when your out of range. They'll give you a good 500m heads up and your flying away that the signal is getting a bit shaky.

CJ
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Old Mar 03, 2012, 02:14 AM
Registered User
San Marcos, CA
Joined Aug 2009
2,826 Posts
Awesome! Thanks! My TX/RX probably will quit way before 2.3km... around 1.5km.. so I should be safe with these.. Waiting until the 600mw VideoTX is back in stock and order the hole package.
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Old Mar 03, 2012, 02:26 AM
um.. yeah, I can make that fly
Carlos230023's Avatar
United Kingdom, Milton Keynes
Joined Jun 2007
3,703 Posts
Good call. The immersion stuff is great. Oh and should you fancy going a little further 'a' field later on (say with a UHF TxRx setup) a helical VRx antenna will take this system to 10km. FYI a new immersion 600mw 5.8VTx is on the "soon to be released" roster. Same thing but a smaller package if space is a constraint.

CJ
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Old Mar 03, 2012, 02:54 AM
Firepower
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North Brisbane, Australia
Joined Mar 2010
3,109 Posts
I must not be flying enough as the CL and SPW antennas are going rusty.

The rust does not seem to effect the video but have not tried at a distance since the rust. Guess the rust would effect the range.

So I suppose the answer is clean off the rust and spray some clear coat on them?

Col
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Old Mar 03, 2012, 05:05 AM
No you cant fly it.
kicekilla's Avatar
United States, CA, Ridgecrest
Joined Mar 2011
1,257 Posts
Quote:
Originally Posted by Firepower View Post
I must not be flying enough as the CL and SPW antennas are going rusty.

The rust does not seem to effect the video but have not tried at a distance since the rust. Guess the rust would effect the range.

So I suppose the answer is clean off the rust and spray some clear coat on them?

Col
ibcrazy posted a ways back about soaking rusting antennas in some type of acid to chemically change the rust into a protective layer (i think haha) hopefully he sees this and can correct and add to this if im wrong.
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Old Mar 03, 2012, 05:32 AM
Still flying a desk..
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United Kingdom, High Wycombe
Joined Sep 2001
1,855 Posts
Quote:
Originally Posted by markus123456 View Post
Not really sure wether I understand your question right or not. If by "feeder" you refer to the complete 50 ohm coax cable from tx/rx to the antenna, and if it's length is important, then the answer is "no". Ok, every real world cable has a damping, and obviousely with the very low powers we actually use you want it to be as short as practical, but it does not matter if the cable is any sort of divideable by a wave, half wave or quarter wave lenght.

"The full wafe above the ground plane".... Hmm, maybe you mean the distance of the antenna itself above other objects? Every antenna has a so called near field which is about a wave lenght around the antenna. ANY object within this range of the antenna will change it's behaviour quite a bit. It would change the radiation pattern as well as the resonant frequency. The reason is that the electormagnetic waves travel trhough the air with very close to the speed of light. Any object however will change their speed trough that matter a little bit, so also non conducting materials count. At the borders of such an object, an effect similar to light hitting the surface of water can be observed. The waves change their direction, hence the changed radiation pattern. So haveing an object in the nearfield of the antenna is a very bad idea. It's an extremly bad idea if said object is even conducting, like i.e. a transmitter or receiver housing.

So in the context of the first part of your question, a cable should be at least one wave lenght long, but if it's a wee bit longer or quite a bit longer does not matter except for the damping effect.

Hope this answers your questions

Markus
Thanks Marcus, that cleared things up for me. It's 30 years since I last played with aerials and lengths of co-ax. I was taught the length (in multiples of velocity factor * wavelength) of the co-ax affects the performance of the antenna.
However, the minimum distance from the antenna to other objects makes a sound argument so I'll stick to keeping the antenna at least one full wave from the TX casing.
Mitch.
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Old Mar 03, 2012, 07:05 AM
Firepower
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North Brisbane, Australia
Joined Mar 2010
3,109 Posts
Quote:
Originally Posted by kicekilla View Post
ibcrazy posted a ways back about soaking rusting antennas in some type of acid to chemically change the rust into a protective layer (i think haha) hopefully he sees this and can correct and add to this if im wrong.
Thanks - Just found it.

----------------------------------------------------------------------------------------------------------------------------------------------------------
It will be just fine. You can paint it to protect the antenna if you like. If it rusts, dip it in phosphoric acid. The phosphoric acid converts rust into iron-phosphate which is a good insulator and protector.

-Alex
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Old Mar 03, 2012, 07:38 AM
H19
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United States, ME, South Portland
Joined Feb 2011
187 Posts
sorry for my stupidity,
Im going to start making this antenna, for 1280MHz, 1.3GHz setup,
and im a little confused about the length of the RG316 coaxial cable,

is this the quarter-wave length ?

1280MHz = 2.36"/60mm, ??

what happens if its longer? it looks alot longer in the pictures,

is it true, or false, the clover-leaf should go onto my TX/quad? im going to side solder it so i can mount it off the back side of the quad?
and the
Skew-Planer-Wheel- on my RX ?

thank you for helping my stupididty
john
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Old Mar 03, 2012, 09:34 AM
vin diousse
Joined Nov 2011
155 Posts
hi,
I've found in my stock a nice RG316 pigtail but the only wire i could find in my stock was a 75 ohms satellite cable. As it is a 1mm diameter wire i thought it was good to give a try. I've been following IBcrazy dimensions for 1260mhz. I didn't test yet.
Is 75ohms wire OK?
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Old Mar 03, 2012, 12:45 PM
No you cant fly it.
kicekilla's Avatar
United States, CA, Ridgecrest
Joined Mar 2011
1,257 Posts
Quote:
Originally Posted by Firepower View Post
Thanks - Just found it.

----------------------------------------------------------------------------------------------------------------------------------------------------------
It will be just fine. You can paint it to protect the antenna if you like. If it rusts, dip it in phosphoric acid. The phosphoric acid converts rust into iron-phosphate which is a good insulator and protector.

-Alex
Cool glad you found it!
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Old Mar 03, 2012, 01:14 PM
Registered User
Joined Nov 2010
687 Posts
That's good question, if gold plated memory wire works as antenna, it would seem any reasonable wire would work, how about 1/64 steel braid, yes, you would have to weld it, but as a crash proof dangling antenna on a plate frame quad....
IBC's earlier statement "go fly it and see..." is the best idea, I get trapped in this "box" of looking for best, easy, quick, cheep, that I end up doing nothing...

I'm going to do some yard work, and then go fly some... Then fly some more, maybe, if I'm not tired, I'll start soldering Vtx / rtx up...he he
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Old Mar 03, 2012, 03:02 PM
H19
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United States, ME, South Portland
Joined Feb 2011
187 Posts
went to home depot today,

they had the .030 Lincoln copper coated welding wire,
the .035 was not copper covered,

so i bought a roll of the .030,

can i use this for the cloverleaf, and the skew-planer wheel ?

also they had RG59 cable,,but no RG58,
can that be used??
i was afraid to waste my money buying some,

im using 1.3GHz
1280MHz
thanks
john
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