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Old Dec 30, 2011, 11:32 AM
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I would use hot glue if i had any
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Old Dec 30, 2011, 11:38 AM
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Alex or Hugo

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

Thanks,
Neal
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Old Dec 30, 2011, 02:55 PM
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Originally Posted by Nobert View Post
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
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Old Dec 30, 2011, 10:15 PM
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Markus is absolutely right.

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

-Hugo
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Old Jan 01, 2012, 06:59 AM
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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
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Old Jan 01, 2012, 08:29 AM
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Originally Posted by TheNiceGuy View Post
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
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Old Jan 01, 2012, 10:19 AM
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Quote:
Originally Posted by TheNiceGuy View Post
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
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Old Jan 02, 2012, 10:46 AM
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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)
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Old Jan 02, 2012, 10:49 AM
I think it'll work this time!!
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Quote:
Originally Posted by TexasAggie View Post
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?
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Old Jan 02, 2012, 10:55 AM
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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)
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Old Jan 02, 2012, 11:36 AM
I think it'll work this time!!
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Originally Posted by TexasAggie View Post
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
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Old Jan 02, 2012, 11:37 AM
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1280 MHz. I'll just do some experiments with it and see its performance.
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Old Jan 02, 2012, 11:38 AM
I think it'll work this time!!
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Originally Posted by TexasAggie View Post
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.
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Old Jan 02, 2012, 02:14 PM
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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.
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Old Jan 02, 2012, 02:27 PM
I think it'll work this time!!
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Originally Posted by TexasAggie View Post
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
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