Antenna Basics For RC Flight: Polarization

[@saniabearsky]

damn, I went as far as 8 years back, and still learned something today. incredible

[@beach-time]

I listen carefully. solder carefully. Mount carefully. The constant results tend to be good. Except for the brain spasms I consistently experience as I optimize everything. I learn more from you then anywhere else. Not even the TED talks can hold a candle to you

[@ExpressiveImagery]

Great explaination, first time I've seen this in an easy to understand manor. Thanks for creating and sharing.

[@UniversalPioneer]

Great info. Thank you for putting in the time and making these kind of videos.

[@djilly75]

Wow 6 years ago! I don't think I even knew what fpv was then 😆

[@WHEATSFPV]

Another great video, informative, and thank you ! I was wondering if the length of reciever antenna would ever affect the polarization? I currently am rebuilding a quad and I have one longer receiver antenna, and one shorter which i transplanted from an FRsky xm mini (it's a bit shorter than my other free antenna)

[@MrBuddy7798]

can you do this again with the new stuff

[@davidrichardson8394]

So which is better, two antennas laying flat 90 degrees from each other, two antennas pointing up 90 degrees form each other, or what most people fly now, two antennas one up and one level with the horizon?

[@exidous6831]

Your best alignment would be with the antennas at 90* from each other in a fashion that is closest to how the craft fly's the most. A V sticking up or down is probably best. Straight out the back is probably a worst case scenario. You want the signal perpendicular to the ground are you are usually travelling parallel to it. Your TX antenna should be kept vertical.

[@noktrnl123]

Patrick Smith what about for freestyle or diving?

[@exidous6831]

PitbullOnAcid there isn't a whole lot you can do about free style. Just get it away from the carbon if you can as it does not pass signals through it well at all.

[@MrHandsomejackuk]

thanks for this explanation great stuff

[@dpkgray]

Joshua, for circular polarized antennas, why is it recommended that the Tx antenna have four lobes and the Rx have three lobes (or vice versa)? Why not just make them match?

[@AmisCorolla]

Hi. Do you have video or can you make one, or do you have any links to antennas, if i want uprage my dji stock drone receiver and drone antennas to better one. i need my drone in work and there is hills and trees. i lost signal some time in 200m when flying low. So i need to do something. i have rc receiver

[@healingbench3198]

Disregard my previous video comment about doing this video. Well done.

[@terriblepeanuts9476]

With respect to what you said at 14:28, if you use a circular polarized antennae on your goggles and a linear (diversity or single) antennae on your quad, does it matter if the one on your goggles is LHCP or RHCP?

[@JoshuaBardwell]

No, it doesn't matter if the CP antenna is paired with a linear one.

[@brisketbaron]

Awesome!

[@DangerDavefpv]

i have alien with x4r-sb is it bad that ive had the antennas crossed when coming out receiver and then seperated when mounted on back off standoffs like your video shows. There overlapping when coming out of receiver

[@tomaszwac]

Circular antennas aren't used for control probably because size of antenna depends on wavelength (frequency). That would mean pretty damn large cloverleaf on your quad @ 2,4GHz ;-)

[@exidous6831]

It's the size and lack of necessity. The signal data rate is so low for control that a weak signal will still perform well enough. 5.8 being used for video is pretty much solely because of the antenna size.

[@jackdaniels7913]

You can however use one as your transmitter for a little better coverage iBcrazy said it once he just didn't like the size and fragile eliminate but it does give a better over all performance I have recently asked him about using a pepper box on 2.4ghz as a ground station and he also said it will work grate ! Long range 2.4ghz with no power booster hell ya.

[@Frogzy]

wait so i need to just put my diversity antennas at 90 degrees and it will be perfect. i mean it will be the best way to mount your antennas?

[@JoshuaBardwell]

That is the ideal alignment for a diversity setup under most conditions.

[@realandthebandit2535]

Hey Josh. Love the channel. Hey I think I messed up my crossfire antenna on my Tango by setting it next to my speakers all night for charging. Any way I can retune the antenna? Will it return to normal after awhile? Maybe make a video about retuning and warn folks against making the same mistake I did? Cheers.

[@JoshuaBardwell]

I actually have no idea what you're talking about. An antenna is just a piece of wire in a certain shape. How can you mess up a piece of wire other than by physically deforming it?

[@realandthebandit2535]

Magnets in the speaker changing the polarization of the wire in the dipole.

[@jaysonragasa7902]

what can you say about the "L" position of two antennas, like FrSky V8R4-II? That's how I usually position of the antennas on my miniquad

[@jaysonragasa7902]

+Jayson Ragasa on other note, since my Rx antenna position is L, on my transmitter, I have my antenna positioned at 45 degrees

[@JoshuaBardwell]

+Jayson Ragasa An L is still 90 degrees. Putting the antenna at 45 degrees is probably neither helping nor hurting unless you fly straight and level most of the time.

[@jaysonragasa7902]

+Joshua Bardwell Most flyers I see, (I usually do fast fly, acro, flips and all that stuff) had their antenna positioned on top with V configuration, while I'm the only guy whose my antenna is at L position, means one standing, and one horizontal. Well they said, V is better, but when I think of the radiation pattern (since the Rx antennas are dipole configuration) I don't see why V is better.

[@JoshuaBardwell]

Jayson Ragasa If you imagine like a long-distance FPV plane, where it is usually going to be level and nose-out or nose-in, then you could try to orient the antennas one way to maximize reception. But for a proximity copter, where it will constantly be spinning and flipping, it just doesn't matter. All that matters is that the antennas are 90 degrees to each other. Actually, I slightly take that back. One reason why V might be better than L is that V is more likely to get the antennas away from the frame of the copter, whereas L is likely to have one antenna close to the frame of the copter, which will hurt reception. But from the perspective of polarization, it doesn't matter.

[@jaysonragasa7902]

+Joshua Bardwell Thank you !

[@kennethholland1502]

I am curious how a straight wire antenna has polarize characteristic. I feel you are confusing 2.4ghz and 5.8ghz transmission

[@JoshuaBardwell]

I am not. A straight wire antenna puts out a linearly polarized signal. If you don't believe me, you can look up many different references for RF basics.

[@fpvdreams8190]

Hello Joshua. I’m curious to know about the receiver that came with my turnigy evolution controller. It came with one antenna. I have seen it with the usual two antennas. Anything you can enlighten me with on this ?

[@JoshuaBardwell]

Some have one and some have two. The ones with two are better,.

[@DennisSantos]

But a cloverleaf antenna doesn't rotate, either mechanically or electronically. It just radiates 3 or 4 different "lobes" at a skewed angle. Does that really make them circular polarised or is the term used loosely?

[@JoshuaBardwell]

You're confusing the radiation pattern with the polarization. Polarization refers to the phase alignment of the E (electric) and H (magnetic) fields as they radiate from the antenna. Every part of an antenna's radiated signal contains both an E and H component, which are the result of an oscillating AC current in the radiator. The E and H component have a frequency, then, and they have a phase relationship. That phase relationship defines the polarization of the signal. Meanwhile the direction in which energy is radiated defines the coverage pattern. Coverage pattern and polarization are two totally independent characteristics of the signal.

[@Frogzy]

wait so i need to just put my diversity antennas at 90 degrees and it will be perfect. i mean it will be the best way to mount your antennas?

[@sunsetpark_fpv]

I dont know why but I am not getting any audio on this vid :(

[@kylecarter6375]

how the hell are you so smart dude?!!??!! (excuse my language) But seriously did you go get your masters in programming and other electronics??

[@thespencerowen]

At 5:02 the antennas are positioned 90 degees from each other but on the same axis. Would it be better to be 90 degrees and on separate axises?

[@JoshuaBardwell]

I don't think what you're describing is possible. Two parallel lines will always define a single plane.

[@thespencerowen]

Joshua Bardwell I derp. 90 degrees is the same regardless if parallel or perpendicular to the plane of the quad. Face palm.

[@wasian4]

Spencer Owen, Don't feel bad, I thought the same thing for a sec before I realized what Joshua was saying haha

[@wasian4]

Joshua, does your comment about the transmitter orientation mean we should be holding it with the antenna pointed upward to maximize the signal?

[@mattdoesstuff2668]

I can confirm you're not the only derp. I thought the same thing.

[@user-qq4wu8sc2k]

Are there any receivers with three diversity antennas?

[@JoshuaBardwell]

Not for RC. Not that I know of. However, the Spektrum Satellite system is something like that. By adding more satellite receivers, you are essentially adding more diversity antennae.

[@user-qq4wu8sc2k]

Thanks for answer. That is unclear for me why developers don't add third antenna to receivers. Making reciver with three antennas placed 90 degress to each other looks like ideal solution to achive good signal level from any direction. And I have one more question. Is quadcopter's carbon frame radiotransparent? I have idea to hide my antennas between carbon layer of my quad to protect them. Is it safe to do? Thanks for answer again.

[@briano70]

If there was a receiver with 3 antennas wouldn't it be called a triversity antenna?

[@user-qq4wu8sc2k]

I think yes. Triversity is the more accurate name. :)

[@karolkrajewski9098]

I was wondering why Joshua have so old chrome then i looked at date 😆