The Skew-Planar Wheel circular polarized omni antenna - Page 6 - RC Groups
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Dec 04, 2011, 07:46 AM
Eat-Sleep-Work-Fly-Repeat
Grips's Avatar
whoa.. no kidding about how the lower the mhz the larger the antenna.. Has anyone put one of these 900mhz antennas on a plane? Any issues with durability from regular flying?
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Dec 04, 2011, 08:10 AM
Team White Llama!
gundamnitpete's Avatar
Quote:
Originally Posted by Grips
whoa.. no kidding about how the lower the mhz the larger the antenna.. Has anyone put one of these 900mhz antennas on a plane? Any issues with durability from regular flying?
lots of people have, great antenna.

As far as durability, most people just bend them back after a big crash. They tend to stand up well, depending on where you put them. Even a slightly out of shape CL still works great, and at 900mhz it's alot easier to "eyeball it".

That picture does make it look larger than it is The shape of the thing misleads you about it's size.
Dec 04, 2011, 07:45 PM
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by RaptorAP
My new portable ground station, works good!!
That's what I use

-Alex
Dec 04, 2011, 07:47 PM
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by Grips
whoa.. no kidding about how the lower the mhz the larger the antenna.. Has anyone put one of these 900mhz antennas on a plane? Any issues with durability from regular flying?
The antenna will hold up fine if you use .035-.045" welding wire. Making it at 900 MHz is a real pain. It is not easy trying to get all the lobes to stay put. This is why I no longer make them. It's takes me entirely too long.

-Alex
Dec 05, 2011, 04:09 PM
Registered User
Quote:
Originally Posted by Grips
whoa.. no kidding about how the lower the mhz the larger the antenna.. Has anyone put one of these 900mhz antennas on a plane? Any issues with durability from regular flying?
I use a 910mhz cloverleaf on the top of the stabilizer on my Skywalker and it does not affect the flight in any way.

pc_pilot
Dec 06, 2011, 01:52 AM
Registered User
I've got a 900Mhz SPW that I'm planning on mounting on a quad. Big antenna on a small quad, big problem right?

2 questions;
A)will a gopro within 10cm affect it too much?
B) As I'm still waiting for a SMA-F adaptor, I'm keen to play around with it. I was planning on running a short distance (<300m) with CP to linear. I should expect about 3db of loss is that correct? Is there any other reason I shouldn't be doing this?

Thanks!
Dec 06, 2011, 04:49 AM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by smarm
I've got a 900Mhz SPW that I'm planning on mounting on a quad. Big antenna on a small quad, big problem right?

2 questions;
A)will a gopro within 10cm affect it too much?
B) As I'm still waiting for a SMA-F adaptor, I'm keen to play around with it. I was planning on running a short distance (<300m) with CP to linear. I should expect about 3db of loss is that correct? Is there any other reason I shouldn't be doing this?

Thanks!
A) -> possible. GoPros are notorioiusly know for their IME radiation. Pack it in silverfoil if needed. If I'm not mistaken, there are sides of the GoPro which are radiating heavier than others, so maybe placing it differently helps. By all means make a serious range test!

B) Nope, nothing wrong with trying. You loose the 3dB, that's it.

Markus
Dec 06, 2011, 05:10 AM
SILURIA / UK
Shikra's Avatar
Alex, I read on one of the posts on Hugo's thread I think that you have to remove resistor from the airwave rx module inside the sharks for any of the Closed Loop antennas. Because of DC bias used

Is that true? Does it make much difference?

I ask, because I only tested my antennas on the sharks - and I very carefully made several including 3,4 and 8 lobe variations of SPW,Turbine and clover. Didn't really notice any improvement over omni with 2.4.


Quote:
Originally Posted by IBCrazy
That's what I use

-Alex
Dec 06, 2011, 06:56 AM
Registered User
Quote:
Originally Posted by Shikra
Alex, I read on one of the posts on Hugo's thread I think that you have to remove resistor from the airwave rx module inside the sharks for any of the Closed Loop antennas. Because of DC bias used

Is that true? Does it make much difference?

I ask, because I only tested my antennas on the sharks - and I very carefully made several including 3,4 and 8 lobe variations of SPW,Turbine and clover. Didn't really notice any improvement over omni with 2.4.
Im using the skew on my FS Dominators and it works fine, must be the older FS models.
I noticed less dropouts/multipathing over the stock dipole omni.
Dec 06, 2011, 12:58 PM
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by Shikra
Alex, I read on one of the posts on Hugo's thread I think that you have to remove resistor from the airwave rx module inside the sharks for any of the Closed Loop antennas. Because of DC bias used

Is that true? Does it make much difference?

I ask, because I only tested my antennas on the sharks - and I very carefully made several including 3,4 and 8 lobe variations of SPW,Turbine and clover. Didn't really notice any improvement over omni with 2.4.
It's only an issue with the FatShark Aviators.

-Alex
Dec 08, 2011, 09:31 PM
QiW
QiW
Registered User
sorry but i read earlier about lawmate receivers not doing good with spw or cl.
i could not find info on that and solving the lawmate vrx issue... or is it still an issue ?
i have recently acquired a lawmate vrx since i heard about how good it can be vs generic chinese vrx.
thanks
Dec 09, 2011, 12:23 AM
Expat
Quote:
Originally Posted by QiW
sorry but i read earlier about lawmate receivers not doing good with spw or cl.
i could not find info on that and solving the lawmate vrx issue... or is it still an issue ?
i have recently acquired a lawmate vrx since i heard about how good it can be vs generic chinese vrx.
thanks
That was an isolated special problem. There is no problem with LMRX and these antenna.
Dec 10, 2011, 10:02 AM
QiW
QiW
Registered User
thanks...
Dec 28, 2011, 03:41 PM
I think it'll work this time!!
Chairwolf's Avatar

My first SPW Antenna


Well, here it is, my first attempt at an SPW antenna for my RX. It's 910 mhz. Works so far on the bench, so I went ahead and gooped it up with hot glue.

This antenna was made from a Rubber Ducky antenna from HK. I had to do this because the connectors on the HK VRX are not SMA connectors; so I disassembled the dipole part of the RD and used the coax that was inside. I kept the joint on the connector and hot glued the top end. Then I mounted the clover-leaf end inside a GLAD container.

I'm going to try a ground test today and see how it does with my cloverleaf VTX antenna.

Stand by!

Bob
Dec 28, 2011, 03:48 PM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by Chairwolf
Well, here it is, my first attempt at an SPW antenna for my RX. It's 910 mhz. Works so far on the bench, so I went ahead and gooped it up with hot glue.

This antenna was made from a Rubber Ducky antenna from HK. I had to do this because the connectors on the HK VRX are not SMA connectors; so I disassembled the dipole part of the RD and used the coax that was inside. I kept the joint on the connector and hot glued the top end. Then I mounted the clover-leaf end inside a GLAD container.

I'm going to try a ground test today and see how it does with my cloverleaf VTX antenna.

Stand by!

Bob
Bob,

Nice work! The drag of that GLAD container will be enormous though....

Markus
Dec 28, 2011, 03:56 PM
I think it'll work this time!!
Chairwolf's Avatar
I don't think my receiver will even notice!
Dec 30, 2011, 01:41 AM
Navigator
volto's Avatar
Quote:
Originally Posted by Chairwolf
I don't think my receiver will even notice!
It will if the wind picks up
Dec 30, 2011, 07:50 AM
Registered User
Very nice, Bob! Nice work!
Dec 30, 2011, 09:07 AM
Registered User

Made antennas


Yesterday I made my first 5.8 Ghz circular polarized antennas. Cloverleaf turned out nicely but Skew-Planar Wheel was a bit messy. I put too much epoxy on Skew-Planar Wheel. Now I need to test these antennas to see how they perform. Used RG58 coaxial cable.
Last edited by Lauri1000; Dec 30, 2011 at 01:21 PM.
Dec 30, 2011, 09:21 AM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by Lauri1000
Yesterday I made my first circular polarized antennas. Cloverleaf turned out nicely but Skew-Planar Wheel was a bit messy. I put too much epoxy on Skew-Planar Wheel. Now I need to test these antennas to see how they perform.
Looking at the fourth picture from the right makes me wonder what may remains in those what it looks 2.4Ghz whip antennas? Usually such antennas are so called pot antennas where there is a metal tube forming one part of a dipole and the center wire the second pole. Now, since your antennas are what seems to be at the far end of the original antenna, I truly wonder if you took the tube out?

Markus
Dec 30, 2011, 09:23 AM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by Lauri1000
Yesterday I made my first circular polarized antennas. Cloverleaf turned out nicely but Skew-Planar Wheel was a bit messy. I put too much epoxy on Skew-Planar Wheel. Now I need to test these antennas to see how they perform.
Ok, I recon that this is eventually just RG58 cable?
Dec 30, 2011, 09:32 AM
Registered User
It's just RG58 cable, nothing more
Dec 30, 2011, 10:06 AM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by volto
It will if the wind picks up
Hopefully not! Here's a shot of my brand-new BMGS. (That's Belly-Mounted Ground Station ) I wear the GS with a strap around my neck, right above my belly. My RC Transmitter is strapped below it TO the GS. I can fly with my hands in the "normal" position, and hold my RC TX up above the GS if I need to look at my RC Transmitter (or use it to block the sun).

Flight tested this system yesterday, and it works like a champ!

The SPW and Clover Leaf antennas are performing EXTREMELY WELL, at least in the eyes of this FPV Noob!

Thanks Alex, and everyone else for your help and support!

Bob
aka
Chairwolf
Last edited by Chairwolf; Dec 30, 2011 at 10:15 AM.
Dec 30, 2011, 10:07 AM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by RaptorAP
Very nice, Bob! Nice work!
Thanks! I feel like I'm bringing a cake to the field every time I put that thing in the car! ha ha
Dec 30, 2011, 10:14 AM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by Lauri1000
Yesterday I made my first circular polarized antennas. Cloverleaf turned out nicely but Skew-Planar Wheel was a bit messy. I put too much epoxy on Skew-Planar Wheel. Now I need to test these antennas to see how they perform.
The shape looks good! Nice work. (I can really say that, because mine are the result of about 4 feet of wire going into the trash can first!!! )

Bob

edit - I just noticed that you mentioned using epoxy. I was thinking - I broke my SPW on the bench right after I bench tested it, and had to re-solder the top (signal) connector. If you use hot glue, and the antenna breaks later, you can melt the hot glue off and fix the antenna. It would be difficult to do (maybe even impossible) with epoxy. So you may want to give hot glue a try for your next one!

No criticism, just food for thought if it might be of some help.

Great work!

Bob
Last edited by Chairwolf; Dec 30, 2011 at 10:19 AM.
Dec 30, 2011, 12:32 PM
Registered User
I would use hot glue if i had any
Dec 30, 2011, 12:38 PM
Registered User
Nobert's Avatar
Alex or Hugo

Based on the last couple of posts, will epoxy or hot glue detune the antenna--- especially on 5.8?

Thanks,
Neal
Dec 30, 2011, 03:55 PM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by Nobert
Alex or Hugo

Based on the last couple of posts, will epoxy or hot glue detune the antenna--- especially on 5.8?

Thanks,
Neal
I'm Neiter Alex nor Hugo, but what makes you think the antenna was tuned in the first place?

If you change the velocity factor of the surrounding medium of an antenna you will change the resonant frequency, and in almost all cases lower the efficiency of the antenna. So strictly speaking the answer is yes. By what degree is another question.

Have you bought a fine tuned antenna that is optimized for a given freuqency? If so you can be concerned. If not why would you botter? If you build an antenna on 5.8Ghz to measure, chances are you are ~100Mhz or even more off anyways. So, applying the hot glue or epoxy does change it, but if you are lucky it could be to the better, maybe to the worse. Nobody will be able to tell you unless you measure your antenna out with apropriate equipement.

Markus
Dec 30, 2011, 11:15 PM
Registered User
Hugeone's Avatar
Markus is absolutely right.

I found that hot glue affect tuning more than epoxy which affect more than CA.

-Hugo
Jan 01, 2012, 07:59 AM
Expat
Can anyone tell me the effect of lengthening the gap between the in/out solder pints on the antenna (that is, where the lobes connect to the SMA center shaft)? I made a 2.4 SPW/CL combo, and worried about a short, made the gap about 8mm on the SPW. What effect does this have as opposed to a 1mm gap?
Thanks
Jan 01, 2012, 09:29 AM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by TheNiceGuy
Can anyone tell me the effect of lengthening the gap between the in/out solder pints on the antenna (that is, where the lobes connect to the SMA center shaft)? I made a 2.4 SPW/CL combo, and worried about a short, made the gap about 8mm on the SPW. What effect does this have as opposed to a 1mm gap?
Thanks
I'm no expert, but the posts I've seen say that the smaller the gap, the better. You could insulate the joints with, say a little piece of electrical tape or something to keep them from touching each other.

Bob
Jan 01, 2012, 11:19 AM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by TheNiceGuy
Can anyone tell me the effect of lengthening the gap between the in/out solder pints on the antenna (that is, where the lobes connect to the SMA center shaft)? I made a 2.4 SPW/CL combo, and worried about a short, made the gap about 8mm on the SPW. What effect does this have as opposed to a 1mm gap?
Thanks
Not 100% sure I understood you right, but if the center conductor piece is just longer up until it meets the lobes, that would increase the resonant frequency slighty and at the same time lower the efficiency of the antenna. However, that's a generalisation. Depending on how your lobes are repositioned because of this it also could have the oposite effect. What's clear thoug is that the efficiency will drop because the shape is not ideal.

That does not mean though that the antenna is unuseable. Just that you don't get the optimum possible. For a first attempt it's ok, so fly your antenna (after makeing some range tests) and see for yourself how good it is.

Markus
Jan 02, 2012, 11:46 AM
Gig 'Em!
TexasAggie's Avatar
My first SPW attempt turned out pretty nicely. I'll put up pictures in a little while. One question: In the below video, the angles that are supposed to be about 17 degrees turned out to be about 40 degrees in mine. Is this okay or should I redo it?

The Skew-Planar Wheel (SPW) circular polarized omni antenna by IBCrazy (1 min 11 sec)
Jan 02, 2012, 11:49 AM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by TexasAggie
My first SPW attempt turned out pretty nicely. I'll put up pictures in a little while. One question: In the below video, the angles that are supposed to be about 17 degrees turned out to be about 40 degrees in mine. Is this okay or should I redo it?
That sounds like either the length of your arcs is way too long, or your ground legs are not at 90 degrees to each other. I am a rank noob at this, but with 40 degrees of overlap, something must be wrong somewhere.

Can you give us a good top-down pic?
Jan 02, 2012, 11:55 AM
Gig 'Em!
TexasAggie's Avatar
I did it with 4 separate leaves, each of which had the same geometry as the cloverleaf that I have already completed (according to http://rcexplorer.se/page14/CPantennas/SPW/SPW.html)
Jan 02, 2012, 12:36 PM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by TexasAggie
I did it with 4 separate leaves, each of which had the same geometry as the cloverleaf that I have already completed (according to http://rcexplorer.se/page14/CPantennas/SPW/SPW.html)
This is 910mhz, right? The only thing I can think of is that Alex's measurements for the cloverleaf antenna on the long piece of wire was 26.5" and the SPW shows 26.0" which might explain why your SPW has a bigger overlap. I would also check your measurements on the legs; they should be 84mm each.

I'm just guessing here, but checking those measurements is where I'd start.

Then again, if the antenna works well, maybe you can just go with it!

Bob
Jan 02, 2012, 12:37 PM
Gig 'Em!
TexasAggie's Avatar
1280 MHz. I'll just do some experiments with it and see its performance.
Jan 02, 2012, 12:38 PM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by TexasAggie
1280 MHz.
ok, then my numbers don't apply. (oops) But if you look at the lengths on the 2 different RCGroups threads, they may be slightly shorter on the SPW antenna than they are on the Cloverleaf.
Jan 02, 2012, 03:14 PM
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TexasAggie's Avatar
My SPW didn't perform as well as my cloverleaf with another cloverleaf on the Tx so I'll take that one apart and try again.
Jan 02, 2012, 03:27 PM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by TexasAggie
My SPW didn't perform as well as my cloverleaf with another cloverleaf on the Tx so I'll take that one apart and try again.
I just checked the lengths on Alex's posts -

for 1280mhz:

Cloverleaf:

Long wire: 18.9" or 479.5mm for the Cloverleaf on 1280mhz.
Short wire: 9.44" or 240mm for the Cloverleaf on 1280mhz.
Quarter Wave: 2.36" or 60mm for the Cloverleaf on 1280mhz.

Skew Planar Wheel:

Long wire: 18.49" or 469.8mm
Short wire (not listed, but 1/2 would be 9.245") or 234.82mm
Quarter Wave: 2.31" or 60mm

I don't know if this was the cause of the problem, but I hope it might help!

Bob
Jan 02, 2012, 03:33 PM
Gig 'Em!
TexasAggie's Avatar
The wire length he lists for 1280 (18.49"/469.8mm) and the quarter wavelength (2.31"/60mm) do not work out. He says the 60mm should be an eighth of the wire length. I'll try 235mm for each leaf (I was using 240, which the CL dimension) this time and see how that ends up.
Last edited by TexasAggie; Jan 02, 2012 at 03:40 PM.
Jan 02, 2012, 03:43 PM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by TexasAggie
The wire length he lists for 1280 (18.49"/469.8mm) and the quarter wavelength (2.31"/60mm) do not work out. He says the 60mm should be an eighth of the wire length. I'll try 235mm for each leaf (I was using 240, which the CL dimension) this time and see how that ends up.
Sounds good! I hope your trash can has less wire in it than mine!!
Jan 02, 2012, 03:46 PM
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TexasAggie's Avatar
Well I bought a 2lb spool of welding wire, so it has the potential to be stuffed...
Jan 02, 2012, 03:56 PM
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TexasAggie's Avatar
Here's where the discrepancy exists: his quarter-wave metric calculations are screwy. 75168/1280 = 58.7 NOT 60. The lengths in his photos also don't agree with his computations.
Jan 02, 2012, 04:05 PM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by TexasAggie
Here's where the discrepancy exists: his quarter-wave metric calculations are screwy. 75168/1280 = 58.7 NOT 60. The lengths in his photos also don't agree with his computations.
Don't forget to add a little for the hooks and the tail on the ground side.
Jan 02, 2012, 04:07 PM
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TexasAggie's Avatar
I'm leaving the hooks off of this one, and the tails don't matter since they're attached when the center conductor is shielded.
Jan 02, 2012, 07:29 PM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by TexasAggie
My first SPW attempt turned out pretty nicely. I'll put up pictures in a little while. One question: In the below video, the angles that are supposed to be about 17 degrees turned out to be about 40 degrees in mine. Is this okay or should I redo it?
40 degrees is a lot. Try it out. If they perform good enough for what you are after - who cares! If not, you found one point to improfe.

It seems like the relation of the arc length compared to the two legs is not ok then. Usually the arc should be about half the wafelength, the legs about a quarter. Note though that the correction factor to apply differs between the SPW and the CL antenna.

HTH

Markus
Jan 03, 2012, 09:39 AM
Engineer for Christ
IBCrazy's Avatar
TexasAggie - You might find the little hooks help a lot. They won't harm anything at 1.3GHz. I make them as long as the feedpoint gap so the overall lobe lenght is consistent.

The lobes should be .5% longer than 1 full wavelength depending on the wire thickness you use. Wire thickness will change resonant wavelength, so the little details will change. Generally the thicker the wire, the higher the resistance (I know this sounds backwards but we're talking RF, not DC). My calculations were done with .035" wire. if you use thinner wire (say .030 or .025) you will need the lobes to be slightly longer than my calculations.

-Alex
Jan 03, 2012, 10:19 AM
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TexasAggie's Avatar
I've got .030 welding wire. So do I need to add the length of the hook to the lobe length, or get the lobes correct and then just bend the last few mm into the hook? Also, how important is that 105 angle? Without another dimension, I find that it can be physically anywhere in a fairly large range. Seems 115 gives a nice-looking lobe. That dashed line on the left is tangent to the arc at the corner.

Edit: I'm going to be doing the trick in your YouTube video with the legs, so I'll make 4 independent lobes.
Last edited by TexasAggie; Jan 03, 2012 at 10:44 AM.
Jan 03, 2012, 10:28 AM
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TexasAggie's Avatar
Since you're here, Alex, can you take a quick look at my FPV test flight from yesterday and give any troubleshooting tips you can think of? 1280 MHz. Tx is a generic 400 mW from RMRC. Rx is Lawmate unmodified. Both antennas were cloverleafs. The transmitter antenna was slightly better-made than the receiver antenna. I highly doubt the problem is due to the Tx turning off in flight, since I replaced all my wiring.

www.youtube.com/watch?v=l7lb99DZL4I
Jan 03, 2012, 12:50 PM
Engineer for Christ
IBCrazy's Avatar
Texas Aggie - I bend my hooks after I strip the cable. The length of the hooks = feed gap length. The reason is that the feed gap counts as part of your lobe length. Therefore by bending the hooks in the end you remove that length from the lobe itself but it gets added back in the soldering stage due to the feed gap. If you had no feed gap at all you would need to add a little wire for your hooks.

The arc isn't too critical. Just be sure it doesn't touch the adjacent lobe.

When I look at your video, your problem appears to be external interference. Perhaps a pulsed transmission? I can't tell. Your video is rock solid and then suddenly loses the frame sync. This would indicate an outside source.

-Alex
Jan 03, 2012, 12:56 PM
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TexasAggie's Avatar
Thanks for the tips. I really appreciate your help. I'm kind of surprised at video interference since that park is basically in the middle of a forest with no built-up areas for several miles.

Also, when you say "slightly longer" for the .03 wire, can you quantify?
Jan 03, 2012, 01:44 PM
Registered User
Nobert's Avatar
TA

Here in Tucson the public services all use the 1280 band. They have a lot more power and can interfere with FPV setups.
Hope this helps.

Neal
Jan 03, 2012, 01:50 PM
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TexasAggie's Avatar
How did you find this out?
Jan 03, 2012, 04:46 PM
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Nobert's Avatar
I have friends in Police, Fire and EMT.
Neal
Jan 03, 2012, 05:52 PM
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TexasAggie's Avatar
Well, here's #2 for 1280 MHz. How's it look? I ended up getting the lobes to be positioned such that I didn't need the hooks to solder the middle.
Edit: I used 107 degrees for the lobe angle. The overall length of each lobe was 245mm and I bent at 60mm from each end.
Last edited by TexasAggie; Jan 03, 2012 at 06:20 PM.
Jan 03, 2012, 06:10 PM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by TexasAggie
Well, here's #2 for 1280 MHz. How's it look? I ended up getting the lobes to be positioned such that I didn't need the hooks to solder the middle.
Looks great. If you were precise with the measures, I'm sure it will perform nicely.

Markus
Jan 03, 2012, 06:17 PM
14s 180mah should be enough...
IFLYOS's Avatar
Quote:
Originally Posted by Nobert
TA

Here in Tucson the public services all use the 1280 band. They have a lot more power and can interfere with FPV setups.
Hope this helps.

Neal
Neal, I am sorry, but this isn't possible. In the US, Amateur radio operators have exclusive use of 1240 Mhz to 1300 Mhz.

Now, it is possible there is a repeater in the 1.2Ghz band for Amateur use*, and that is causing the interference you refer to, but again, 1240-1300Mhz is allocated by the FCC for exclusive Amateur use. We do share some of our allocations with other groups, but not this one.

see http://www.ntia.doc.gov/files/ntia/p...3-allochrt.pdf for the breakdown of allocations in the US

Tim
AG4RZ

I just looked, and there is an Amateur repeater located at 9200 ft atop Mt Lemmon neat Tucson, Arizona - This is a D-Star machine. It is on 1298.25...
Last edited by IFLYOS; Jan 03, 2012 at 06:20 PM. Reason: Added info
Jan 04, 2012, 09:09 AM
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by TexasAggie
Well, here's #2 for 1280 MHz. How's it look? I ended up getting the lobes to be positioned such that I didn't need the hooks to solder the middle.
Edit: I used 107 degrees for the lobe angle. The overall length of each lobe was 245mm and I bent at 60mm from each end.
Darn good if you ask me. Now fly it

-Alex
Jan 04, 2012, 10:04 AM
Gig 'Em!
TexasAggie's Avatar
Quote:
Originally Posted by IBCrazy
Darn good if you ask me. Now fly it

-Alex
Thanks. First I have to hot glue it a bit and then make another cloverleaf since I stepped on my best one yesterday.
Jan 09, 2012, 08:37 AM
Registered User
Ok so I built the SPW for the first time and it looks alright but performs awful. I recorded a LOS flight and upon reviewing the vid, there is no way anybody could fly fpv with this.

There are slight problems with my antenna. After reading I think the problem is my feed gap. I measured mine to be 9.5mm and I did not incorporate any hooks into the center joint.

Both Tx and Rx antennas are RHCP (RHCP = tractor prop, LHCP = pusher prop?) and the Tx antenna is a CL. I am on 1280 MHz.

should I bend hooks to be ~10mm or should I just shorten the feed gap or both?

I have a 5-turn helical that I just set flat on the ground and that works fine for flying around LOS or ~ 300-700 feet without pointing it - I have not flown far yet but at least I know my other components are working.
Jan 09, 2012, 11:19 AM
Registered User
asaloca's Avatar
Hi.
Congrats for IbCrazy ant his valious contribuiton here and for the amazing jeweller work some of you are sowing here for us !!

Can somebody tell me a supplier ...Home Depot or were you guys in states are buying the " Copper coated steel wire " ....serched the net and noyhing ..

Tks
FRED
Jan 09, 2012, 11:31 AM
Registered User
2 kinds of plated wire:

Gold plated 'memory wire' - found in ladies DIY jewelery stores.

Copper plated 'MIG welding wire' - found in lots of places that sell welding equipment.

HTH

Nigel.
Jan 09, 2012, 11:31 AM
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TexasAggie's Avatar
I got a 2lb spool of welding wire at Ace. They also had it at Lowe's.
Jan 09, 2012, 11:51 AM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by asaloca
Hi.
Congrats for IbCrazy ant his valious contribuiton here and for the amazing jeweller work some of you are sowing here for us !!

Can somebody tell me a supplier ...Home Depot or were you guys in states are buying the " Copper coated steel wire " ....serched the net and noyhing ..

Tks
FRED
Harbor Freight has it for cheap, too. And Home Depot.
Jan 09, 2012, 01:39 PM
Registered User
I found it at radio shack marketed as antenna ground wire. It is copper clad steel wire and had a cost of about $1/foot or something like that.
Jan 09, 2012, 02:36 PM
I think it'll work this time!!
Chairwolf's Avatar
$1 A FOOT??? You can get 10 miles of it for $11.47 at Home Depot, or $8.50 at Harbor Freight!
Jan 10, 2012, 04:03 PM
Registered User
Zen09's Avatar
Quote:
Originally Posted by chemnut842
Ok so I built the SPW for the first time and it looks alright but performs awful. I recorded a LOS flight and upon reviewing the vid, there is no way anybody could fly fpv with this.

There are slight problems with my antenna. After reading I think the problem is my feed gap. I measured mine to be 9.5mm and I did not incorporate any hooks into the center joint.

Both Tx and Rx antennas are RHCP (RHCP = tractor prop, LHCP = pusher prop?) and the Tx antenna is a CL.
A pusher prop behaves the same as a tractor one.

RHCP is the conventional clockwise screw thread type.
Jan 11, 2012, 03:53 PM
Registered User
I have 5.8 system on order and came across this:

http://www.readymaderc.com/store/ind...roducts_id=596

Do I need 2 antennas, one for Tx, one for Rx or just for Tx is fine? Thanks in advance for your help.

Quote:
Originally Posted by IBCrazy
That will do 1000+ feet with ease.

-Alex
Jan 11, 2012, 04:25 PM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by k0mputer
I have 5.8 system on order and came across this:

http://www.readymaderc.com/store/ind...roducts_id=596

Do I need 2 antennas, one for Tx, one for Rx or just for Tx is fine? Thanks in advance for your help.
You need a pair. A cloverleaf on the transmitter and skew planar wheel on the receiver usually works best.

Markus
Jan 11, 2012, 05:17 PM
Registered User
Quote:
Originally Posted by markus123456
You need a pair. A cloverleaf on the transmitter and skew planar wheel on the receiver usually works best.

Markus
Hey there, cool thanks. Where can I get the skew planar wheel for 5.8 though? I googled it, no sellers found.
Jan 11, 2012, 05:42 PM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by k0mputer
Hey there, cool thanks. Where can I get the skew planar wheel for 5.8 though? I googled it, no sellers found.
Alex sells them:

http://videoaerialsystems.com/

So does Hugo

http://www.truerc.net/canada/

I make them upon request, but I currently have a too big backlog to help you out unless you like to wait.

Markus
Jan 11, 2012, 05:47 PM
Registered User
Quote:
Originally Posted by markus123456
Alex sells them:

http://videoaerialsystems.com/

So does Hugo

http://www.truerc.net/canada/

I make them upon request, but I currently have a too big backlog to help you out unless you like to wait.

Markus
I've seen that site http://videoaerialsystems.com/ but no option to add product to cart.

For http://www.truerc.net/canada/, they had the wind mill for 5.8. Is that the same as the skew planar wheel?
Jan 11, 2012, 06:18 PM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by k0mputer
I've seen that site http://videoaerialsystems.com/ but no option to add product to cart.

For http://www.truerc.net/canada/, they had the wind mill for 5.8. Is that the same as the skew planar wheel?
The windmill is not the same, but they work the same. In a sense they are interchangeable (Hugo forgive me)!

I've seen on the webpage that they are "on vacation", maybe you have to wait for some days more, but again, Hugo's antennas work equally well.

Markus
Jan 12, 2012, 10:03 AM
Engineer for Christ
IBCrazy's Avatar
I will second the work of Hugo (www.truerc.net/canada). His work is exceptional which is why he and I design together. All of our products are compatible. The True Wire windmill/fan combination will do the same as my BluBeam set and both are compatible with eachother. You can get my BluBeams from here: http://www.readymaderc.com/store/ind...roducts_id=550 I know he's out of stock, but I am sending him a shipemnt this afternoon so he'll be back in stock in no time

-Alex
Jan 12, 2012, 10:37 AM
Registered User
Thanks for all the good information. So for a 5.8, I can get the cloverleaf for the TX and make the SKP for now, which is my first time, so I could mess it up. Should I just get the Bluebeams Alex mentioned?

Quote:
Originally Posted by IBCrazy
I will second the work of Hugo (www.truerc.net/canada). His work is exceptional which is why he and I design together. All of our products are compatible. The True Wire windmill/fan combination will do the same as my BluBeam set and both are compatible with eachother. You can get my BluBeams from here: http://www.readymaderc.com/store/ind...roducts_id=550 I know he's out of stock, but I am sending him a shipemnt this afternoon so he'll be back in stock in no time

-Alex
Jan 12, 2012, 11:16 AM
Registered User
Zen09's Avatar
Finished my first SPW, for 1180MHz. I've made it from 1mm steel wire.

Now I have to test it with the CL against stock antennas.

I'll keep it in a foam box (raw foam melt and cut to fit the antenna) to protect during transport. I think I'll keep it during running as well, the foam shouldn't affect it much would it.
Last edited by Zen09; Jan 12, 2012 at 11:26 AM.
Jan 12, 2012, 02:55 PM
Engineer for Christ
IBCrazy's Avatar
^ Wow! That is some nice work there. You will really like your new antenna system.

-Alex
Jan 15, 2012, 09:58 AM
France
Hi everybody, I’m new to the forum, I do practice FPV with a Multirotor MK, in France, I have been reading your post here on antennas from A to Z, and I have found it fascinating.
I did create, thanks to yours informations, my Pinwheel and Cloverleaf antennas and they do work unbelievable (only itch is: to be careful the way you land not to make a pancake out of it)…

My question: how important is the length of the feed point, should it change with frequency, does it change impedance, does it matter at all?

Second question: should the length of the lobes of the Cloverleaf (for a pair of matching antennas) be longer than those of the Pinwheel?? (I have found contradictory opinions on the matter)

Mike
Last edited by Vertige; Jan 15, 2012 at 04:00 PM.
Jan 15, 2012, 03:03 PM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by Vertige
Hi everybody, Iím new to the forum, I do practice FPV with a Multirotor MK, in France, I have been reading your post here on antennas from A to Z, and I have found it fascinating.
I did create, thanks to yours informations, my Pinwheel and Cloverleaf antennas and they do work unbelievable (only itch is: to be careful the way you land not to make a pancake out of it)Ö

My question: how important is the length of the feed point, should it change with frequency, does it change impedance, does it matter at all?

Second question: should the length of the lobes of the Cloverleaf (for a pairs of matching antennas) be longer than those of the Pinwheel?? (I have found contradictory opinions on the matter)

Mike
Mike,

Yes, keep the feedpoint as short as possible and yes, the CL lobes should be about 2 - 3% longer than the lengt of the SPW.

Markus
Jan 15, 2012, 03:59 PM
France
Quote:
Originally Posted by markus123456
Mike,

Yes, keep the feedpoint as short as possible and yes, the CL lobes should be about 2 - 3% longer than the lengt of the SPW.

Markus
Thanks Markus for the info.

Mike
Jan 20, 2012, 11:34 PM
Registered User
thehaw24's Avatar
Does anyone know where i can purchase the Cable to build this antenna? Home depot,radio shack, Im not trying to order online.

Thanks
Jan 20, 2012, 11:41 PM
Registered User
Home Depot

Quote:
Originally Posted by thehaw24
Does anyone know where i can purchase the Cable to build this antenna? Home depot,radio shack, Im not trying to order online.

Thanks
Jan 21, 2012, 02:06 PM
Registered User
thehaw24's Avatar
Quote:
Originally Posted by k0mputer
Home Depot
What is it called, Im looking for the cable not the copper coated wire..
Jan 21, 2012, 10:30 PM
Registered User
Hi Guys, I'm very new to FPV. Sorry if this question was already asked 1000s of times and also answered that much I just cant find the answer.

I've got Fat Shark Predator RTF FPV Headset System 5.8GHz. It comes with 100mW transmitter and 3dBi antenna. If anybody use it, how far is the operation range of this system?

How much is Skew-planar wheel antenna capable to extend the range?

Thanks,
Ruben
Jan 22, 2012, 01:09 AM
Navigator
volto's Avatar
Quote:
Originally Posted by thehaw24
What is it called, Im looking for the cable not the copper coated wire..
It's RG316 coaxial, but any 50 ohm coaxial will do. Radio shack is probably the only one likely to have it, I get mine on ebay with the SMA connectors already crimped on.
Jan 22, 2012, 01:22 AM
'FPV'er...not a "LOS'er
Vantasstic's Avatar
Quote:
Originally Posted by volto
It's RG316 coaxial, but any 50 ohm coaxial will do. Radio shack is probably the only one likely to have it, I get mine on ebay with the SMA connectors already crimped on.
Radio Shack will probably have the SMA connectors, but likely not the RG316 wire. You may find it at a local ham radio store?
Jan 22, 2012, 02:48 PM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by thehaw24
What is it called, Im looking for the cable not the copper coated wire..

Here you go...

item.mobileweb.ebay.com/viewitem?itemId=150590703162&index=21&nav=SEARCH&n id=22318907212

Bob
Jan 22, 2012, 11:38 PM
Registered User
thehaw24's Avatar
Thanks for the info guys, I ended up buying everything i needed from radio shack, I got the sma connectors and the cable is a RG58,Here is a picture.
And video with the antennas, Im verry happy with them now i can go anywhere i want without problems..
Witespy quad FPV with clover leaf antennas (3 min 34 sec)
Feb 04, 2012, 10:15 PM
Dixie Normious
Eastcoast78's Avatar
got my cables form eBay

spent last night making them
Skew Planer Wheel and Cloverleaf Build (1 min 42 sec)


Hopefully they work good.
Feb 07, 2012, 04:40 AM
Registered User
a little bit of my creativity....

building Cloverleaf and Skew-Planar antennas (16 min 3 sec)
Feb 09, 2012, 10:14 PM
Registered User
Alex, Markus, Hugo

I'm interested in building a 2.4g SPW for my Frsky Rx but would like to use the existing coax because of the ufl/ipx connectors on them. The other coaxs mentioned are very heavy and I'm afraid that moving the antenna around could disconnect it without my noticing. The diameter is 1.13 mm [OD insulation] and I can't find a name or label for the stuff. So the question is; what effect would this smaller diameter coax have on measurements, lengths etc? I have .031 brass rod for this use.

Richard
Feb 10, 2012, 02:59 AM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by The Tellurian
Alex, Markus, Hugo

I'm interested in building a 2.4g SPW for my Frsky Rx but would like to use the existing coax because of the ufl/ipx connectors on them. The other coaxs mentioned are very heavy and I'm afraid that moving the antenna around could disconnect it without my noticing. The diameter is 1.13 mm [OD insulation] and I can't find a name or label for the stuff. So the question is; what effect would this smaller diameter coax have on measurements, lengths etc? I have .031 brass rod for this use.

Richard
Richard,

You can use this cable as it's also 50 ohms. The difference to the bigger ones is that it has a much higher damping factor, alas make sure to only have it as short as possible. Good luck with soldering it to the antenna lobes!

Markus
Feb 10, 2012, 11:45 AM
Registered User
Quote:
Originally Posted by markus123456
Richard,

Good luck with soldering it to the antenna lobes!

Markus
Thanks Markus

Yes I've been mulling over how to do that, must make a jig of some sort. I have some brass tubing that just a hair larger than the outer diameter of the cable and will try soldering to that [lot of heat] then solder that to the shield [gentle heat]. I plan to solder only the top and have the tube go down over the outer insulation. Is this good or no?

A second question regarding that is if this brass tube is extended down over the outer insulation about 20mm [28mm maybe better?] similar to the balun on a linear dipole will it adversely affect the antenna? The idea is to use it as tension relief.

Last resort is to use a ufl/ipx to sma adapter cable Frsky others but I've not found one yet.

Richard
Feb 11, 2012, 05:15 AM
Registered FPVer :)
markus123456's Avatar
Quote:
Originally Posted by The Tellurian
Thanks Markus

Yes I've been mulling over how to do that, must make a jig of some sort. I have some brass tubing that just a hair larger than the outer diameter of the cable and will try soldering to that [lot of heat] then solder that to the shield [gentle heat]. I plan to solder only the top and have the tube go down over the outer insulation. Is this good or no?

A second question regarding that is if this brass tube is extended down over the outer insulation about 20mm [28mm maybe better?] similar to the balun on a linear dipole will it adversely affect the antenna? The idea is to use it as tension relief.

Last resort is to use a ufl/ipx to sma adapter cable Frsky others but I've not found one yet.

Richard
Richard,

ufl/ipx adaptors can be found on ebay.

The idea with the tubing is not a good one as in fact would form a balun which you don't want with CL and SPW antennas. You could make a very small washer though. That's what I actually use on my antennas. You could cut off about one milimeter of the mesh and route that through the washer, then bend the mesh out and solder it onto the washer. This gives you a platform that is cabable of dissipiating some of the heat onto which you can solder the GND connections of the lobes. The HF influence with this "horizontal" little ring is acording to my experience negletable.

HTH

Markus
Feb 11, 2012, 08:51 PM
Registered User
Thanks for the reply Markus

The tube idea started to look like more of a pain the more I looked at it so thats good to know, I like the washer idea. Copper washers are available here if a small enough one can be found. There was also someone who made a Y or X out of copper that I could do otherwise. Been playing with it today making jigs etc. The real pain is the feed wire which is microscopic in gauge.

Richard
Feb 12, 2012, 10:26 PM
Build Something
subsonic's Avatar
So whatís the best way to mount a 980mHz SPW antenna for a receiver? I like to do FPV from inside my car Ė comfy seats and am wondering what the requirements are for a simple solution. Do I need to have the antenna up on a pole, or can I have it on my ground station box on the carís roof or hood?

Cheers, Michael.
Feb 13, 2012, 08:24 AM
Engineer for Christ
IBCrazy's Avatar
Quote:
Originally Posted by subsonic
So whatís the best way to mount a 980mHz SPW antenna for a receiver? I like to do FPV from inside my car Ė comfy seats and am wondering what the requirements are for a simple solution. Do I need to have the antenna up on a pole, or can I have it on my ground station box on the carís roof or hood?

Cheers, Michael.
I'd recommend up on a stand about 2-3 feet above the car's roof. This will minimize reflections from the car.

-Alex
Feb 13, 2012, 12:39 PM
Registered User
Quote:
Originally Posted by markus123456
Richard,
. The HF influence with this "horizontal" little ring is acording to my experience negletable.Markus
Would that also be true at the other end? The wire on the active side is micro size as in 3 or 4 strands of 46 gauge or something. Hooking the ends as Alex does just overwhelms this little wire and any tension on it from the elements can snap it off at the exit from the shielding. I'm thinking that if I put hooks on facing down and out, bring them into the washer from the top, solder as such then that could be squeezed down to the center wire and soldered, this could work.

Richard
PS. would like to avoid buying separate u.fl to SMA adapters cables
Feb 13, 2012, 01:23 PM
I think it'll work this time!!
Chairwolf's Avatar
Quote:
Originally Posted by markus123456
You could make a very small washer though. That's what I actually use on my antennas. You could cut off about one milimeter of the mesh and route that through the washer, then bend the mesh out and solder it onto the washer. This gives you a platform that is cabable of dissipiating some of the heat onto which you can solder the GND connections of the lobes. The HF influence with this "horizontal" little ring is acording to my experience negletable.

HTH

Markus
Markus,

I've been thinking about doing this on my next antenna build. I could probably make a tiny washer out of a piece of copper or brass, using a drill press, by just drilling the proper size hole, trimming the O.D. to the rough shape, and then mounting the piece in the drill chuck on a screw and sanding or filing it round.

But I'm wondering if anyone knows of a source of pre-made small washers of the size we'd need to use on RG316 cable?

Thanks,

Bob


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