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Old Jul 23, 2012, 10:53 PM
USA, NY, Brooklyn
Joined Jan 2002
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http://www.rcgroups.com/forums/showp...&postcount=476

check this post, he explains that we are supposed to subtract the width of the part from the active element. also a problem with that guys antenna is, his active element is too high, ibcrazy says the distance between the ground (bottom of the antenna) and where the active element meets the 3/4 lobes should be tiny...
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Old Jul 23, 2012, 11:36 PM
airplanes r made from aluminum
wilem's Avatar
United States, SC, Darlington
Joined Jul 2009
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went with separate lobes.... we'll see how it turns out.. now to wait on fee bay seller to send my rp sma connectors
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Old Jul 24, 2012, 01:20 AM
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Australia, QLD, Brisbane
Joined Feb 2011
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Quote:
Originally Posted by KillerCut View Post
For the Skew Planar Wheel
individual lobes =
Wire length in mm = 300672.5/f in MHz

Quarter length
Quarter wavelength in mm = 75168/f in MHz

So for 5800mhz:
4 wires at 51.84mm
bend them at 12.96mm
I dont think that is right for the individual lobe method as that is just the length of the double lobe divided by 2. Alex made allowances for the extra bends that are part of his double lobe method that will throw it out when doing individual lobes.

See the discussion below between Devonboy and Alex copied from the first page of the SPW thread.

Quote:
Originally Posted by Devonboy View Post
Alex,
Your frequency numbers are off - from the links the calculations are +4% over normal frequency calculations and I quote:

N.B. Testing and analysis has shown that the elements should be
slightly more than one wavelength long ( WL x 1.0443 ).

The factors to use are: 31329 / F (centimeters) or 12334 / F (inches) long.

This antenna is broad in frequency response. In practice, element lengths are not supercritical.

/Edit
Quote:
Originally Posted by IBCrazy View Post
Nigel,

I think you should see how I built it. My numbers are double those numbers. Why? I'm using 2 wires instead of 4 Your factors are for each element. My wire encompasses 2 elements to make this easier to build.

-Alex
Quote:
Originally Posted by Devonboy View Post
OK - get your idea now.

Only thing I can see is that the elements will be slightly off centred with your method.
I wonder whether this will have a detrimental effect to the CP pattern or not?

From my previous attempts at CP, the slightest deviation or miscalculation and CP is affected.

Both OMM and my builds were with 4 individual elements.

Nontheless, it's good to experiment

Nigel.
So, i just wanted to clarify if Nigels factor (31329 / mhz) is the one to go with for a individual lobe construction method on the SPW (giving a lobe wire length of 54.01mm and quarter wavelength bend of 13.5mm)

and If this is correct what is the factor for a CL???
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Old Jul 24, 2012, 01:47 AM
Because gas is for BBQ's
nogas's Avatar
Australia, QLD, Brisbane
Joined Feb 2011
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Quote:
Originally Posted by KillerCut View Post
http://www.rcgroups.com/forums/showp...&postcount=476

check this post, he explains that we are supposed to subtract the width of the part from the active element. also a problem with that guys antenna is, his active element is too high, ibcrazy says the distance between the ground (bottom of the antenna) and where the active element meets the 3/4 lobes should be tiny...
Yes, i asked this exact question a few months back when i was building mine.

The length of the horizontal arm needs to be shortened by the distance from the outside of the signal insulator to the centre of the signal wire. the diameter of the insulator on RG316 is .8mm from memory, so i subtracted .4mm

And also the length of the angled (upper) arm needs to be shortened by the length the signal wire projects out of the stripped shield "feed gap". My feed gap was only about .5mm so the length i subtracted there was .5mm.
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Old Jul 24, 2012, 02:44 AM
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Switzerland, LU, Buchrain
Joined Aug 2006
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Quote:
Originally Posted by wilem View Post
i only ask because i want to know how to build my own.. i would just buy them but mine are rp sma...and i dont like adapters on anything. i changed one but i am not taking apart my goggles to replace the connector,.

additionally i like the way Alex only uses 2 wires v/s 4
Just in case, I custom build and fine tune antennas for you with SMA or RP-SMA connectors and whatever frequency as you or anyone else likes.

Markus
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Old Jul 24, 2012, 10:38 AM
airplanes r made from aluminum
wilem's Avatar
United States, SC, Darlington
Joined Jul 2009
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Quote:
Originally Posted by markus123456 View Post
Just in case, I custom build and fine tune antennas for you with SMA or RP-SMA connectors and whatever frequency as you or anyone else likes.

Markus
well after a few attempts you may very likely get to do that...
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Old Jul 24, 2012, 10:41 AM
airplanes r made from aluminum
wilem's Avatar
United States, SC, Darlington
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Quote:
Originally Posted by nogas View Post
Thank wilem, but i should have mentioned i prefer making mine with individual lobes (not paired as per Alex's method) so i cant use the measurements in his tutorial as they are slightly longer due to the extra bends etc.

I did find this post by Devonboy today which might be what i'm looking for



So if I am working towards 5800mhz , using single lobes i think each lobe needs to be 54.01mm long (31329 / 5800 for the SPW) before bending and the quarter wavelength will be 13.5mm, does this sound right???
my individual lobe from Alexs numbers came up to the same as the cloverleaf pages calculator. 13.59 oops actually 54.38
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Old Jul 24, 2012, 12:16 PM
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IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
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Words of wisdom:

"He who builds to every mans advice shall have a crooked huose."

-Chinese proverb

Find one person's advice and stick to it. For the cloverleaf build, a single lobe should be 52.9mm in total length. For a skew wheel, the lobe should be 51.8mm. For both of these, you must subtract the gap distance at the feed.

-Alex
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Old Jul 24, 2012, 12:18 PM
airplanes r made from aluminum
wilem's Avatar
United States, SC, Darlington
Joined Jul 2009
653 Posts
Quote:
Originally Posted by IBCrazy View Post
Words of wisdom:

"He who builds to every mans advice shall have a crooked huose."

-Chinese proverb

Find one person's advice and stick to it. For the cloverleaf build, a single lobe should be 52.9mm in total length. For a skew wheel, the lobe should be 51.8mm. For both of these, you must subtract the gap distance at the feed.

-Alex
so very true. thanks for the tip Alex.

data point (54.38) i did not subtract the feed line distance but i am learning a ton and i like that

the practice one. I know it needs to be tightened up at the base and the base dia compensated for the next one will be better.





By weezbadimageshac at 2012-07-24

upside down in an attempt to show the lobes seem to be equal in height..these things ar difficult to photo


By weezbadimageshac at 2012-07-24
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Last edited by wilem; Jul 24, 2012 at 12:54 PM.
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Old Jul 24, 2012, 03:16 PM
USA, NY, Brooklyn
Joined Jan 2002
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yay, my cloverleafs are getting better and better. I have picture in areas around my house when there was none before. woohoo, lol.
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Old Jul 24, 2012, 03:49 PM
airplanes r made from aluminum
wilem's Avatar
United States, SC, Darlington
Joined Jul 2009
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Quote:
Originally Posted by KillerCut View Post
yay, my cloverleafs are getting better and better. I have picture in areas around my house when there was none before. woohoo, lol.
cool, i hope to try mine in the next few days..
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Old Jul 24, 2012, 08:56 PM
Because gas is for BBQ's
nogas's Avatar
Australia, QLD, Brisbane
Joined Feb 2011
746 Posts
Quote:
Originally Posted by IBCrazy View Post
Words of wisdom:

"He who builds to every mans advice shall have a crooked huose."

-Chinese proverb

Find one person's advice and stick to it. For the cloverleaf build, a single lobe should be 52.9mm in total length. For a skew wheel, the lobe should be 51.8mm. For both of these, you must subtract the gap distance at the feed.

-Alex
The irony of knowledge - The more we learn, the more we realise we dont know.

It is very hard for us layman to try to filter all the info out there when we dont really fully understand why it is what it is.

Thank you for the above sizes, that helps alot. Looks like my CL's are right but my SPW's need to be adjusted slightly.
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Old Jul 24, 2012, 09:29 PM
USA, NY, Brooklyn
Joined Jan 2002
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here are the best 2 cloverleafs I came up with. The one on the tx is a little better. Please give me comments and suggestions on the setup. Thanks,

I'm not going to make a skew planar for now..

Still some flux on the antennas, gonna clean them up later.
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Old Jul 24, 2012, 11:05 PM
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México, MOR, Jiutepec
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i love these antennas are great CP, Good Video cuality,cheap (if DIY) and kind of cute specially the 5.8 ghz little ones
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Old Jul 25, 2012, 03:54 AM
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België, Brussel, Brussel
Joined Nov 2010
284 Posts
My first attemtp doesn't look very good. I had trouble soldering the 0.6mm copper wire, it just wouldn't stick. Shaping was fine (well good enough for me).

Is flux going to be any good for this (have some coming in the mail)? I thought it was some finishing on the wire so I tried heating it up (hence the black color). It made the wire very soft and attaching a bit better but still not as it should be. Any tips?

I'll try with brass wire this evening. Maybe that is better.

I tested them indoors anyway. Indoors they're good . Maybe they work outside also (I'm waiting on my goggles so I can't test yet).
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