Jul 23, 2012, 09:53 PM USA, NY, Brooklyn Joined Jan 2002 1,943 Posts 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...
 Jul 23, 2012, 10:36 PM airplanes r made from aluminum United States, SC, Darlington Joined Jul 2009 652 Posts went with separate lobes.... we'll see how it turns out.. now to wait on fee bay seller to send my rp sma connectors
Jul 24, 2012, 12:20 AM
Because gas is for BBQ's
Australia, QLD, Brisbane
Joined Feb 2011
746 Posts
Quote:
 Originally Posted by KillerCut 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 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 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 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???
Jul 24, 2012, 12:47 AM
Because gas is for BBQ's
Australia, QLD, Brisbane
Joined Feb 2011
746 Posts
Quote:
 Originally Posted by KillerCut 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.
Jul 24, 2012, 01:44 AM
Registered FPVer :)
Switzerland, LU, Buchrain
Joined Aug 2006
2,926 Posts
Quote:
 Originally Posted by wilem 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
Jul 24, 2012, 09:38 AM
United States, SC, Darlington
Joined Jul 2009
652 Posts
Quote:
 Originally Posted by markus123456 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...
Jul 24, 2012, 09:41 AM
United States, SC, Darlington
Joined Jul 2009
652 Posts
Quote:
 Originally Posted by nogas 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
Last edited by wilem; Jul 24, 2012 at 11:21 AM.
 Jul 24, 2012, 11:16 AM Engineer for Christ Amherst, VA Joined Jun 2006 11,032 Posts 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 Latest blog entry: Project Covert Ops: Long range ground...
Jul 24, 2012, 11:18 AM
United States, SC, Darlington
Joined Jul 2009
652 Posts
Quote:
 Originally Posted by IBCrazy 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.

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

Last edited by wilem; Jul 24, 2012 at 11:54 AM.
 Jul 24, 2012, 02:16 PM USA, NY, Brooklyn Joined Jan 2002 1,943 Posts yay, my cloverleafs are getting better and better. I have picture in areas around my house when there was none before. woohoo, lol.
Jul 24, 2012, 02:49 PM
United States, SC, Darlington
Joined Jul 2009
652 Posts
Quote:
 Originally Posted by KillerCut 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..
Jul 24, 2012, 07:56 PM
Because gas is for BBQ's
Australia, QLD, Brisbane
Joined Feb 2011
746 Posts
Quote:
 Originally Posted by IBCrazy 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.
Jul 24, 2012, 08:29 PM
USA, NY, Brooklyn
Joined Jan 2002
1,943 Posts
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.

Images

 Jul 24, 2012, 10:05 PM Registered User México, MOR, Jiutepec Joined Oct 2011 350 Posts i love these antennas are great CP, Good Video cuality,cheap (if DIY) and kind of cute specially the 5.8 ghz little ones
Jul 25, 2012, 02:54 AM
Registered User
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).