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Old Apr 26, 2012, 10:08 AM
Happy Days
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United States, WA, Mason County
Joined Mar 2001
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Originally Posted by IBCrazy View Post
It will do fine. I actually recommend this to protect the antenna.

-Alex
Cheers Alex, good to know. They look good like that as well
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Old Apr 26, 2012, 11:56 PM
radian 4700
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Canada, QC, Saint-Hyacinthe
Joined May 2011
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5.8ghz SP antenna welding gig

I dont know yet if my antenna are gonna be good, but i think they will be fine. I prefer to solder the inner part first, then it's easyer to lay the antenna on the coax cable for the rest.



The first CL and SP set i made were made with RG58 coax cable and were the first set i made, so the result are not so good as the geometry. Now i use copper wire and gig with RG316, i hope it will help.

any tips would be welcome
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Old Apr 27, 2012, 10:50 AM
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Amherst, VA
Joined Jun 2006
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You are doing it the hard way See my Cloverleaf thread on the first page to see the jigs I have used for years.

-Alex
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Old Apr 28, 2012, 12:08 AM
radian 4700
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Canada, QC, Saint-Hyacinthe
Joined May 2011
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Originally Posted by IBCrazy View Post
You are doing it the hard way See my Cloverleaf thread on the first page to see the jigs I have used for years.

-Alex
That seem much easier, i will try it soon.
why you use different wave lenght for CL and SP?

Quarter wavelength in mm = 76755/f in MHz(Cloverleaf)
Quarter wavelength in mm = 75168/f in MHz(skew-planar wheel)
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Old Apr 28, 2012, 07:07 AM
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Amherst, VA
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Originally Posted by francoishaha View Post
That seem much easier, i will try it soon.
why you use different wave lenght for CL and SP?

Quarter wavelength in mm = 76755/f in MHz(Cloverleaf)
Quarter wavelength in mm = 75168/f in MHz(skew-planar wheel)
Reactive coupling between the lobes results in slightly different resonant lengths.

-Alex
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Old Apr 30, 2012, 06:16 AM
Rotary~myPast,Present &Future!
SINGAPORE
Joined May 2006
2,220 Posts
I wanted to share this joy with you Alex. I would never be able to enjoy such FPV flying without the cloverleaf and the dual helicals. The video is not glitch-free but it is almost perfect to me! From 80% static (horrible video) with the stock linear antennae to 90% steady-video with the CL-Helical combo. It is almost like a dream come true.
MCPX FPV Again - Flying over Cricket Match (2 min 3 sec)
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Old Apr 30, 2012, 07:07 AM
Always soldering
Joined Dec 2011
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Hi Terencechan nice video!

Did you let YouTube to "improve the video"???

Didi the same "shaky" style with one of mines too. I delete and re load the video and dont use that YouTube function the video is OK now.

I remember that also make my OSD start to move all around the screen.

Just a comment. Maybe the video is like this and you are aware.

Maybe you tube said to you "your video is a little fuzzy, want us to fix that?"

Martin
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Old Apr 30, 2012, 07:18 AM
Alicante, Espaņa
Joined Jun 2010
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Hello, I have been reading this webpage http://jcoppens.com/ant/helix/calc.php
and have noticed that it's possible to change the distance from one helix to the next ( coil spacing). For example, you can change from 0.25 wavelenght that Alex use in this tutorial to 0.1 wavelengt. This will result in a smaller antenna. But not only that, as the coils spacing gets smaller, the antenna has better gain.

Is this true?
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Old Apr 30, 2012, 08:26 AM
Rotary~myPast,Present &Future!
SINGAPORE
Joined May 2006
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Originally Posted by Martinba77 View Post
Hi Terencechan nice video!

Did you let YouTube to "improve the video"???

Didi the same "shaky" style with one of mines too. I delete and re load the video and dont use that YouTube function the video is OK now.

I remember that also make my OSD start to move all around the screen.

Just a comment. Maybe the video is like this and you are aware.

Maybe you tube said to you "your video is a little fuzzy, want us to fix that?"

Martin
Hi Martin, actually the source video is wobbly. It was a windy day and the McpX flybarless was trying to fight it. But your right, that YouTube function didn't help much and it made the video look less crisp.
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Old Apr 30, 2012, 09:47 AM
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Amherst, VA
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Originally Posted by catamar View Post
Hello, I have been reading this webpage http://jcoppens.com/ant/helix/calc.php
and have noticed that it's possible to change the distance from one helix to the next ( coil spacing). For example, you can change from 0.25 wavelenght that Alex use in this tutorial to 0.1 wavelengt. This will result in a smaller antenna. But not only that, as the coils spacing gets smaller, the antenna has better gain.

Is this true?
Yes. In fact you can change the spacing at various points along the helix as well. While this does result in gain improvements, it also results in loss of efficiency. I like efficient antennas, so I focused on the most efficient design.

-Alex
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Old Apr 30, 2012, 10:18 AM
Alicante, Espaņa
Joined Jun 2010
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What do you mean with efficiency in this case?. What do I lose exactly when I make a 7 turn helical with 1/4 wavelenght Spacing OR 1/8 wavelenght spacing ?


Quote:
Originally Posted by IBCrazy View Post
Yes. In fact you can change the spacing at various points along the helix as well. While this does result in gain improvements, it also results in loss of efficiency. I like efficient antennas, so I focused on the most efficient design.

-Alex
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Old Apr 30, 2012, 01:26 PM
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Think about it like this: You have a certain volume of air in which you can fly. You can manipulate it any way you want, but you simply cannot make it any bigger.

Now let's say your antenna system drops to 50% efficiency. That cuts your flight volume in half. Thus if I'm looking for more gain, I'd rather find a more efficient design than a helical.

-Alex
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Old Apr 30, 2012, 08:38 PM
radian 4700
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Canada, QC, Saint-Hyacinthe
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I am using the fatshark google with the integrated receiver and i wonder if there is any danger using this equipment so close to the head... anyone got a clue?
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Old Apr 30, 2012, 09:08 PM
Member #1
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Australia, NSW, Picnic Point
Joined Aug 2011
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Just hit a PB on my 5 turn 5.8g helical! Out to 3 klm! Footage was crystal clear on both the helical and a SPW with a 200mw Vtx on ET eagle eyes diversity!

Video up later on.
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Old May 01, 2012, 12:55 PM
Engineer for Christ
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Amherst, VA
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I am using the fatshark google with the integrated receiver and i wonder if there is any danger using this equipment so close to the head... anyone got a clue?
You do use a cell phone don't you? That has more radiation than FPV equipment you are concerned with

-Alex
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