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Last modified: Thu, 1 Sep 2016
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Antennas

When antennas were only used to transmit control signals to RC models, most people didn't pay them much thought. Control signals only contain a tiny amount of data, so modern RC radios rely heavily on redundancy in the form of spreading and/or simply sending the same data multiple times at multiple frequencies. And even if a few packets are lost, it's usually barely noticeable - your model won't fall from the sky just because it loses the signal for a fraction of a second. As a result of all this, you can use horrible antennas and still get decent range (and yes, those tiny wire antennas everyone uses are pretty horrible).

Things are completely different when it comes to FPV. For those who don't know, FPV relies on old-style analog video (NTSC or PAL) because at this time there is no affordable digital system capable of transmitting video with sufficiently low latency to be useful for fast-flying models. Analog video does not provide any redundancy or error correction, so all noise and interference is directly shown on the screen. People quickly realized that the choice of antenna can make a huge difference here.

In these articles I will try to explain a bit what is important in antenna selection and design, in a way which is understandable to people who are not radio engineers. Some aspects are unavoidably of a rather technical nature, so I will have to introduce some theoretical concepts in order to properly explain those.

(This article is still under construction.)



Comments

Rocketnutz

Comment #1: Wed, 31 Aug 2016, 16:59 (GMT+1, DST)

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Thanks for the info.
Watching the review on RCModelReviews now.
Hope to try a set of your item out soon!
Thanks from VA, USA!

Zerog

Comment #2: Wed, 31 Aug 2016, 18:06 (GMT+1, DST)

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I Maarten, great work on the pagoda ;)
I would be very curious to try a pair of your "pagoda" on a quad and review it on our italian blog and forum.
Let me know if you might be interested.

Alias Rik

Comment #3: Wed, 31 Aug 2016, 23:09 (GMT+1, DST)

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I really hope the Pagoda can get a high score in the test Bruce has planned. And if someone make them commercially i hope that for once we can get them, living in Belgium, at a fair price without the usual high shipping cost and without the usual custom fees :)

Mag ne keer gezegd worden, fijn dat iemand van hier de antenne arena instapt en ik duim voor een betere axial ratio tegenover de andere antennes in de test welke Bruce voorzien heeft.

Xtrmtrk

Comment #4: Wed, 31 Aug 2016, 23:16 (GMT+1, DST)

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I too would be interested in buying and trying a pair of your Pagoda antennas. How can we buy them?

Mike Gaines

Comment #5: Thu, 1 Sep 2016, 4:33 (GMT+1, DST)

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Interesting video with RCModelReviews.com. Would be interested in buying a set of your antenna when the final product is brought to market.

Nineninties

Comment #6: Thu, 1 Sep 2016, 19:38 (GMT+1, DST)

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Nice work !!!When will you be posting the design of your Pagoda antenna ?

Maarten Baert

Administrator

Comment #7: Sun, 4 Sep 2016, 17:20 (GMT+1, DST)

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Quote: Zerog

I Maarten, great work on the pagoda ;)
I would be very curious to try a pair of your "pagoda" on a quad and review it on our italian blog and forum.
Let me know if you might be interested.

Quote: Xtrmtrk

I too would be interested in buying and trying a pair of your Pagoda antennas. How can we buy them?

I don't have enough prototypes left to send them out to people, and I have no plans to start selling these myself, I will leave that to the manufacturers.

Quote: Nineninties

Nice work !!!When will you be posting the design of your Pagoda antenna ?

The design files are now online.

Iamfrankenstein

Comment #8: Wed, 7 Sep 2016, 10:39 (GMT+1, DST)

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Hello Maarten,

Could you do a dirtypcb so we can order you pcb's?
(I'll pay for the order cost, If you don't want to i'll understand)
When you order you get the option to share your design, if you get many order you get some money off of it. (which is why i won't do this, as the money obviously should go to you).

If you have gerber files I recommend using http://blog.thisisnotrocketscience.nl/projects/pcb-panelizer-beta/ to panailze them. As it's cheaper to use default sizes of 5x5 or 10x10.

If i can help, please let me know. (I have only done one order my self though)

Heel erg bedankt voor het delen van de theorie en ontwerpen,
Michaël

Maarten Baert

Administrator

Comment #9: Sat, 10 Sep 2016, 0:36 (GMT+1, DST)

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Quote: Iamfrankenstein

Hello Maarten,

Could you do a dirtypcb so we can order you pcb's?
(I'll pay for the order cost, If you don't want to i'll understand)
When you order you get the option to share your design, if you get many order you get some money off of it. (which is why i won't do this, as the money obviously should go to you).

If you have gerber files I recommend using http://blog.thisisnotrocketscience.nl/projects/pcb-panelizer-beta/ to panailze them. As it's cheaper to use default sizes of 5x5 or 10x10.

If i can help, please let me know. (I have only done one order my self though)

Heel erg bedankt voor het delen van de theorie en ontwerpen,
Michaël

While I like the idea, I don't think it makes a lot of sense in this case. Panelization is great to drive the cost down, but only if you really need high quantities. I think most people only want 2-4 antennas, so for them it's going to be cheaper to just order the parts from Elecrow, Seeedstudio, or one of the other cheap low-quantity manufacturers. Unless Dirtypcbs actually allows different designs to be combined in a single panel. Most manufacturers charge a lot extra for this.

Iamfrankenstein

Comment #10: Wed, 14 Sep 2016, 11:52 (GMT+1, DST)

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My remark about panelization was more directed to the fact that in your archive you have 5 lose gerber files. creating a single board with all parts so its single order 14,- for all. By creating one file for both left and right plus part 3 you have a nice 5 of both types.

https://dl.dropboxusercontent.com/u/10750934/antana%27s.png

Maarten Baert

Administrator

Comment #11: Fri, 16 Sep 2016, 2:16 (GMT+1, DST)

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Quote: Iamfrankenstein

My remark about panelization was more directed to the fact that in your archive you have 5 lose gerber files. creating a single board with all parts so its single order 14,- for all. By creating one file for both left and right plus part 3 you have a nice 5 of both types.

https://dl.dropboxusercontent.com/u/10750934/antana%27s.png

Most manufacturers don't allow that though. Well technically they allow it, but they usually raise the price to the point where it's cheaper to order them separately. So that's what I do.

Last modified: Fri, 16 Sep 2016, 2:17 (GMT+1, DST)

Dave855

Comment #12: Tue, 25 Oct 2016, 16:55 (GMT+1, DST)

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Okay I have a few sets up for sale in the USA on www.farvew.com

If there is interest I don't mind ordering the PCBs and making them available in smaller quantity's.

Thanks Maarten!

Lustertone

Comment #13: Mon, 5 Dec 2016, 22:57 (GMT+1, DST)

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A couple of questions...
1 - Will having a covering (such as TPU) that goes around the outside of the two main antenna pcb's but does not go between them affect the performance?
2 - Is the smaller disc acting as a balun for the antenna? If so, can material go between the lower PBC and the smaller disc without affecting performance?

Maarten Baert

Administrator

Comment #14: Wed, 7 Dec 2016, 23:22 (GMT+1, DST)

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Quote: Lustertone

A couple of questions...
1 - Will having a covering (such as TPU) that goes around the outside of the two main antenna pcb's but does not go between them affect the performance?

Yes, but not by a huge amount. It depends on the dielectric constant and density of the material as well as the total volume (i.e. thickness in case of shells).

Quote: Lustertone

2 - Is the smaller disc acting as a balun for the antenna? If so, can material go between the lower PBC and the smaller disc without affecting performance?

Any material near any of the PCBs will have some impact. It is difficult to predict exactly how much. The volume between the second and third (smallest) PCB is less sensitive than the volume between the two top PCBs, but it still has an impact.

If you want to minimize the impact, use a foam with low RF loss, such as styrofoam. Avoid polyurethane (PU/PUR/TPU), it has much higher losses.

Kenadias

Comment #15: Sun, 5 Mar 2017, 0:55 (GMT+1, DST)

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Hey Maarten thanks for your awsome work on the pagoda antenna.
I was wondering if there are any patch antennas that will work with the pagoda for diversity recievers.

Maarten Baert

Administrator

Comment #16: Sun, 19 Mar 2017, 16:43 (GMT+1, DST)

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Quote: Kenadias

Hey Maarten thanks for your awsome work on the pagoda antenna.
I was wondering if there are any patch antennas that will work with the pagoda for diversity recievers.

Any decent circularly polarized patch will work with the Pagoda. I actually have a new patch design coming out in 1-2 months probably, but if you don't want to wait that long, take a look at the patches from SpiroNet or MenaceRC. Or use a helical antenna, those are fine too.

Brooks1977

Comment #17: Thu, 13 Apr 2017, 13:08 (GMT+1, DST)

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Hi Marten,

I've noticed there is a 2B version of your antenna. What are the differences and or the advantages of this revision? Is the spacing the same as version 2?

Thanks for all the hard work!

Maarten Baert

Administrator

Comment #18: Tue, 18 Apr 2017, 0:05 (GMT+1, DST)

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Quote: Brooks1977

Hi Marten,

I've noticed there is a 2B version of your antenna. What are the differences and or the advantages of this revision? Is the spacing the same as version 2?

Thanks for all the hard work!

Read the readme files ;).

The 2B version is re-tuned for use with plastic protective shells, such as the ones sold by MenaceRC and FarVew.

Saboo

Comment #19: Sun, 28 May 2017, 23:32 (GMT+1, DST)

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We use 915MHz for telemetry. Does your simulation software work for the 915MHz range?

Would like to have a design for 915MHz.

Have you worked on other frequency ranges such as 1.2-1.3GHz?

Thanks

Ddale

Comment #20: Sun, 10 Sep 2017, 4:38 (GMT+1, DST)

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Hi Marten,
I saw that you can eliminate one of the pcb's and have the performance of a regular coverleaf my question is which pcb? is it the small one?

Thanks
David

Fernandez

Comment #21: Mon, 16 Oct 2017, 10:51 (GMT+1, DST)

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Possibly we could still gain some extra range, if we implement directly on the PCB of the antenna a decent low noise amplifier stage and maybe small 5.8ghz BPF behind.

I assume based on the low price of our RX modules, the input stages probably not very decent lna....The first stages of RX is most important.

Will make the antenna more expensive and need little bit of power, but like to try it...

Maarten Baert

Administrator

Comment #22: Sun, 29 Oct 2017, 2:36 (GMT+1, DST)

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Quote: Saboo

We use 915MHz for telemetry. Does your simulation software work for the 915MHz range?

Would like to have a design for 915MHz.

Have you worked on other frequency ranges such as 1.2-1.3GHz?

Thanks

A Pagoda antenna for 915 MHz would be way too big and heavy. Just use a cloverleaf instead, at those low frequencies the issues with cloverleafs aren't that bad.

Quote: Ddale

Hi Marten,
I saw that you can eliminate one of the pcb's and have the performance of a regular coverleaf my question is which pcb? is it the small one?

Thanks
David

Yes, the smallest PCB can be removed, but doing so makes the axial ratio significantly worse.

Quote: Fernandez

Possibly we could still gain some extra range, if we implement directly on the PCB of the antenna a decent low noise amplifier stage and maybe small 5.8ghz BPF behind.

I assume based on the low price of our RX modules, the input stages probably not very decent lna....The first stages of RX is most important.

Will make the antenna more expensive and need little bit of power, but like to try it...

In theory yes, but the Pagoda antenna doesn't really have any room where you could place this amplifier. However the Triple Feed Patch antenna has plenty of space, and I have actually considered creating a version that includes a built-in LNA (specifically the SKY65404, which has a noise figure of about 1.2 dB).

W2hro

Comment #23: Tue, 30 Jan 2018, 4:52 (GMT+1, DST)

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Have you designed an RHCP / LHCP antenna for L-Band frequency?

This patch antenna design would be useful as a feed for L-band satellite dishes.

Contact info - w2hro.fn20@gmail.com

Efeksk

Comment #24: Wed, 23 May 2018, 9:31 (GMT+1, DST)

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Hi maarten.
I congratulate you on your work.
You're doing a pretty good job.
Acama Do you have an antenna development plan for 1.2 GHz and 2.4 GHz frequencies?

Maarten Baert

Administrator

Comment #25: Sun, 27 May 2018, 19:35 (GMT+1, DST)

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Quote: W2hro

Have you designed an RHCP / LHCP antenna for L-Band frequency?

This patch antenna design would be useful as a feed for L-band satellite dishes.

Contact info - w2hro.fn20@gmail.com

Quote: Efeksk

Hi maarten.
I congratulate you on your work.
You're doing a pretty good job.
Acama Do you have an antenna development plan for 1.2 GHz and 2.4 GHz frequencies?

I'm not currently working on antennas for lower frequencies due to time limitations, but I may do so in the future.

Hotmultimedia

Comment #26: Wed, 13 Jun 2018, 22:29 (GMT+1, DST)

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Hi. Can you recommend an antenna simulation software?

I'm wondering if it would be possible to design an atleast somewhat operating 5.8GHz antenna that would be embedded within a wooden block.

Maarten Baert

Administrator

Comment #27: Sat, 16 Jun 2018, 16:56 (GMT+1, DST)

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Quote: Hotmultimedia

Hi. Can you recommend an antenna simulation software?

I'm wondering if it would be possible to design an atleast somewhat operating 5.8GHz antenna that would be embedded within a wooden block.

I use HFSS. CST is also good. Both are too expensive for hobbyists though, I can use it through my university.

You can't really embed a 5.8GHz antenna in a wooden block, the absorption of the wood is way too high.

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