Bardwell, you missed the main point. The real advantage of LHCP antennas is that when you search for them, your results aren't filled with music videos from RHCP (Red Hot Chilli Peppers).
Reminds me of a Harry Enfield comedy sketch where some 'youths' were being interviewed and the interviewee asks one of them why he had a tattoo that says "Individual", the 'youth' replies "cos all my mates got one too"
@@licensetodrive9930 It's finally starting to become less popular...but for a few years every single person put FPV in their pilot name. The name that's supposed to differentiate pilots just all looked and sounded the same.
@@PowerScissor That was to let folks know it was a FPV moniker...not just some made up internet name...there weren't many pilots back then and this made it easier to find them and their content!
I find that having both LHCP and RHCP on the goggles works quite well in the specific case of flying micro quads with linear antennas indoors, where signals can bounce every which way and rarely reach the goggles by direct path.
Thanks for the video JB. It inadvertently answered a more technical question I had. I really appreciate how you don't try to act more knowledgeable than you are, you just come straight out and say, "I'm not sure, " or I don't know. Too many people have an issue saying that. And like I said, I did get my answer not despite that good trait of yours, but BECASUSE of it! Thanks again.
this video, I learned something today. I finally got the answer, see I use LHCP in life and to my understanding of this video it does not talk to RHCP. So this explains the reason why my wife never receives to correct information, she MUST be on RHCP.
Another benefit of having a circular polarized on your goggles when having a linear on you quad is that the orientation of the quad now doesn't have an effect on the attenuation (except on the ends). The 3dB loss in this case is much better than having cross polarization with two linear antenna's.
Thanks Joshua, now I know why I am getting very strong losses from rather close between my quad and goggles at fairly close range. LHCP antenna on order.
Question. I once read somewhere that 3 lobe circular polarized antennas were better for transmitting and 4 lobe for receiving. Is that true? And if it is why don't we have more choices for TX 3 lobe and RX 4 lobe? I do remember seeing some that were marked for either TX or RX but almost all aren't.
Ive always gotten them in pairs and the two sets i have say the same as your saying above with using one for the Drone side and one for the Goggle Side..
I fly LHCP because when I started to fly 4 years ago, I flew with many people. We were usually as much as 8, trying to fly in groups of 4. VTx were garbage, people were doing stupid things on the spot like powering when others were flying, not knowing what channel and what band were their VTx, and everybody was struggling. VTx were burning , because the quads were grounded, and we waiting for the video problems to be sold. And since everybody was using RHCP except one (and he was having less problems than the other), I chose to use LHCP myself. And it works, we were 2 peoples watching the other struggling with glitches. Then I was the fastest of the group because instead everyone else, I chose to use Skyzones googles, so I was actually the only person to see were I was going in our all metal mall carpark^^ And since it worked well, I continue to do so!
GPS is a RHCP system, but its harmonic are probably way too low to impact anything we use. But I was wondering if any other common system we use or are in our environment (cities: cell? ..?) could affect circular polarized signals, in either left or right, making the other choice better for certain environment?
i just keep learning more and more ,,,finally something i can still do that doesnt hurt me to bad to do it and thats fly , fly , fly ,,,its so amazing of a feeling i just cant quit dreaming of flying faster and higher and then dive bombing a tree after doing a split S over it.....yayyy i cant wait to see where this road takes me next
A linear antenna’s polarization will change as the orientation changes. Horizontal antenna will equal horizontally polarized and vertical antenna will be vertically polarized. For the best signal both antennas should match each other. Hard to do with a moving quad.
Correct. In an indoor environment this is somewhat mitigated because the reflected signals have polarization that depends on the angle of the bounce. If there are enough bounces, there will be some signal that is mostly aligned.
After reading the title I thought there's not much to learn from this. But as always, Bardwell proved me wrong.. =) I really WAS learning something today.
There is a scenario where you can use both a left and right hand polarised antenna with a diversity reciever while broadcasting from a single polarised antenna on the quad as a reflected signal has opposite polarisation and may be stronger when your quad goes behind an occlusion. As the diversity switches not combines you should not see the mixed polarised cross signal interference during non occluded flight as the opposite polarised antenna will be rejecting the reverse polarisation.
That is my thought as well. All my quads have whips & unless I am flying at a distance, I always use a LHCP & RHCP on my diversity. Very rarely does the signal drop out when the quad is obstructed. For instance, a whoop indoors gets a clean signal all the time where a CP + patch drops out.
@@MilitantPeaceist Yep indoor use is a good example of it's usefulness. It's a shame more recievers don't have 4 inputs then you could have both a LHCP and RHCP long range antenna like pepper boxes or helical or patches.
I'm pretty sure your antenna expert guest you interviewed said that when a polarized signal bounces off an object, it reverses polarity. So if you had one RH-CP on on side of your goggles and a LH-CP on the other side , you would receive those reflections but at a slightly later time (ms's) creating a double image. Would I be wrong to assume that ?
Once a signal bounces off of something it changes polarization. If you have the opposite polarization antenna on your goggles you should still be able to receive the signal after the first bounce (every odd numbered bounce). This is a situation that needs multipath (at least one hop).
Unless the direct LOS is occluded, the LOS will always be stronger than the bounce. The only time opposite polarization is stronger is when it is bouncing around an obstacle.
How do you know what Polarization is on a BetaFPV 65 or 75 Mini whoop?....my camera comes in fine through my FatShark goggles but when checking the camera through my monitor the video is semi scrambled?....is this the problem the wrong Polarization from the whoop to the monitor? Thanks!
Question - if i have linear antenna ( Diople Antenna ) on my goggles and i'm going to build a quad with circular RHCP antenna will it work? ( i know you talked about similar case but example was a bit different - you talked about linear on quad -> cicrular on goggles, in my case its other way around)
Yes it can matter because most antennas and vTX are tuned better to one channel than another. But without test equipment you can't know for sure which channels are best.
Many quads like HappyModel come with a small linear antenna. Instead of using a rubber ducky style linear 5.8Ghz antenna on the goggles, using something like the Menace RC Bandicoot linear patch antenna would be better than either a LH or RH circular polarized antenna. If so, what complimentary antenna would you suggest using diversify? Two Menace linear patches? Thank for your great vids!
what about which side you MOUNT an RHCP or LHCP onto your goggles? Regardless of communication with the the antenna on the drone... I am referring to the mounting side... cuz I am starting out, and im not worried about other pilots as I fly alone... Sooo....with just starting my purchasing of upgrading from the stock antennaes, I can just build around what antenna I have on my goggles... Cuz I dont have any drones; yet.. (ou probably already know that story)
OK, so this might be a stupid question. I only run linear antennas on my quads. Should I not be adding one linear and 1 polorised antenna to my Googles.? Maybe that's why Skyzone gives you those crappy antennas. They will "work" with all quads.
I still would run 2x circular because circular antennas don't depend on the orientation of the other antenna while linear antennas can have up to 15ndn of loss or more of they are cross polarized.
I fly dipoles on almost all my models for weight, durability and the fact they're practically free especially. After testing even a cheap Chinese skew planar seemed to perform way better on the rx than two matching dipoles at 90 degrees to each other, especially in a high multi path environment. I'm not sure why this is but, something that goes against that is I replaced a helical I was using with a bi-quad because bi-quads are linear and the helical seemed to suck with linear. I instantly noticed a big improvement. I'm not a 100% why exactly the skew planar seems to be better considering everything says it should be worse but, one thing that is as the theory suggests is that in an open field the linear antenna's on the rx do give a bit more range with more static and breakup towards the limits when banking a plane or flipping a quad. So for me it's a no brainer to run a sp on the goggles because it provides more reliable coverage close in and indoors or around obstacles and if I want to fly farther out that's what the bi-quad is for. I need to make up some omni directional bi-quads and see if that helps because I kind of wonder if having a loop vs open antenna is the reason it performs better considering the bi-quad performed so much better than a helical. Another thing I would like to try is running two dipoles on a rapidfire or clearview to see if that improves anything.
Simple answer: the circular RX-antenna allways loose 3dB which is not much, but the direction of the linear TX-antenna does not matter any more. This is good because the kwad is rolling and pitching all the time. A linear as RX-antenna looses ~20dB when it is horizontal while the TX is vertical and that is a lot. Here the diversity has to switch all the time just for keeping up with the direction. I use the same trick with my transmitter. I have a 2.4G-cloverleaf on the transmitter because all receivers use that linear wire-antennas. This give me a better range with less failsafes. There is no more need to mount the receiver-antennas 90° to each other but more freedom to mount them so that at least one is not obstructed by the kwad.
When i started out in FPV had seen some where that if you run right on the kwad you run left on the goggles know wonder video has been crap thanks i did learn something today from the master
Yeah but What IF i got an SMA T adapter THEN put a Left and Right Hand polarized stubby antenna on my Qwad, THEN i can have Right hand and Left Hand antennas on my Goggles and not lose diversity. Didnt think about that now did you?? :P you didnt go there so i had to!! :P (just kidding great video as always!! )
@@JoshuaBardwell Dammit Man!!!! just when i thought i had it all figured out ur knowledge rains on my parade!! :P this is why we cant have nice things!! :P
I just sent you a message today talking about Reception issues on Instagram. Then here I am at 10:25 at night and I come across this video. Thank you so much for making this video way back then for me to find now. But if you do have any insight for the VTX that I’m using that I sent you on Instagram, please feel free to reply there.
Have you thought about doing an NTSC vs PAL comparison video? You could call it "NTSC isn't always your PAL" :) The reason I suggest that title is due to dot crawl and rainbow artifacts - detail, and especially RF noise, can cause rainbow 'shimmer' artifacts in an NTSC signal. It looks colourful but makes it more difficult to see the actual detail of the environment you're flying in. I noticed how bad it can get in Rotor Riot's recent video "Winning a Drone Race with Captain Vanover!" where the FPV feed goes super colourful when flying inside the sports hall. PAL has 20% more pixels and doesn't suffer that rainbow affliction but with the slightly slower framerate the footage doesn't look as smooth as NTSC on RU-vid because most people's displays are running at 60hz.
When I had a camera that was switchable between PAL and NTSC, I preferred the PAL signal. It gave a noticeably better picture and the drop in frame rate was not an issue.
What if you are buying a pre made drone and are not sure which antenna is on the aircraft, Im trying to purchase goggles right now and want to make sure I match the antenna. Your videos are amazing !!!
And what about using a 3-way splitter and two antennas on one sma connector? Do these will work better than only one antenna or there will be no difference? Of course both on the same polarization or both linear.
Yes . But Linear polarized will work with both RHCP and LHCP tx antenna. However you loose 50% power. Like using a 100mW over a 200mW one. When used with a dipole, you get 100%, but as long as both are aligned.
This is a tough question to answer. The good thing about linear is, when the polarization lines up, you have 0 dB loss. But if the signal is 90 degrees alignment, you have lots of loss. And the problem with linear is that the alignment of the antenna determines the polarization. So as the quad rotates and turns, the polarization of the signal is constantly changing. In my opinion, this is one really good thing about circular polarized antennas: their polarization is independent of the alignment of the quad. If you have a linear on the quad and a linear on the goggles, then worst-case you could end up with a lot of loss. But if you have a diversity system with two omni antennas 90 degrees to each other, then the chances of cross-polarization are smaller. And if you are in an environment with lots of multipath, then the chances of getting a bounce with "correct" polarization are higher (but on the flip-side, now you are dealing with multipath). In my opinion, it's best to pair linear on the quad with circular on the goggles. You get a constant 3 dB of loss, but the polarization is always "sort of correct" and never "totally incorrect". But in the end, you have to test your specific circumstances and see what works best. Sometimes it will be two linears.
"You're going to learn something today." I think this is the first time I learned nothing from a Joshua Bardwell video. I suppose the title kind of gave it away but you've always been right when you've said I'd learn sometime. I'm not mad, just disappointed. (Apparently I'm also a bit grumpy.) Happy Independence Day everyone.
i have to agree man, this video was scraping the bottom of the idea barrel in a pretty bad way , how about a video on the topic best channel for a specific antenna?
@@TheMadmacs That'd be a rather pointless video too. All these components have imperfections and acceptable levels of variations within their manufacturers QC processes. What would be cool, is a demonstration of some spectrum analysis with a HackRF one or something equivalent to find bands with the least amount of garbage on them in an area not at that property.
@@snfn7847 i think antenna have a fairly pronounced bias to a particular part of the frequencies we use and its not always about QC, the thickness of the wire used is probably a big part of any bias , and also the protection covering the antenna, both of these are not really subject to variation. and even if they arent consistent then that in itself would be useful.
I recently purchased a 4 inch X-Knight and it came with a LHCP antenna. I only have RHCP antennas except for a couple of triple feed patches. I can’t tell any difference running a RHCP with the LHCP. Are you aware any videos demonstrating the effects of mixing antennas? I can’t seem to find any.
You should see reduced range when using LH and RH antenna's together, vs. both the same. If you don't see any difference, one explanation would be that the antennas are not actually strongly polarized.
I really appreciate the quick response thank you. I haven’t noticed any degradation in range. I even switched my triple feed patch over to the LHCP side and it didn’t seem to make any difference.
Or you fly with Eachine EV200D's like me. I have left CP and Left Patch on the left side and Right CP and Right patch on the right side then I have the best of both worlds at races. I can fly with either depending on who i'm racing by just changing my quad antenna and I can spectate no problem :-)
Hi JB. I run a triple feed patch on my ground station with RH pagodas on my craft. What thinks you about the triple feed patch? they are both left and right at the change of the dongle? Happy flying!!!!
Is there actually any Diversity receivers that have more than 2 receivers built-in? i could imagine just plastering everything with patchantennas and get ultimate signal strength :P honestly though - wouldnt it be beneficial to have two or more directional antennas plus a backup omni? or would a system like that be too powerhungry?
@@JoshuaBardwell oh really? Did you make/plan on making a review/informational video on any of those? That'd be really interesting - I mean two antennas on a goggle work really well but wouldn't a "bando groundstation" or something similar be nifty as well?
To be fair you could get better reception at a race with non-rapidfire type diversity system running lhcp and rhcp antennas. The reason being that the high gain secondary antenna will be more susceptible to multipathing (due to the gain) so by eliminating the diversity and forcing use of the low gain antenna you could reduce multipathing at the cost of range which you probably don't need too much. Additionally a lot of race environments are pretty multipathy.
Hi if my goggles have two antennas do i fit two left or two right, or do i just need one and leave other empty cheers anyone, ime looking to upgrade my antennas on my goggles.
Yes there is a better one right hand is better because you have a better selection of antennas for right hand if you're racing you should have both there's not much more discussion after that
