I've done plenty of flying with linear antennas, being on a small budget they go ok. Cheap 200mw tx with supplied antenna, cheap box goggles with supplied antenna and it's still good enough to fly out about 1km at 30mt with a home built fixed wing. You don't need to be all cashed up to have a good time :).
You are wright. For sure people will have a good time flying fpv on linear antennas anyway. And when they upgrade to circular polarized antennas, they will have an even better time :-)
@@EnglishTurbines I understand what you said, we are just talking informally that is possible having a good time on linear, and generally speaking, when you use circular polarized antennas you improve the quality of your reception in most of the cases. But, in some cases, of course linear can do even better.
@@EnglishTurbines I run a 600mW Tx on a RHCP Pagoda in all of mine. Two cars, one plane. The cars? One's nitro, one's electric. The plane? A NexSTAR 46 with a Magnum 52RFS on the nose. I have no problems whatsoever with signal quality on any of these rigs except when the cars go behind trees.
Bruce: Nice job. I'm not sure I perceived as great a difference and you concluded, but I really appreciate your objectivity in test design, and I'm very anxious for your followup using fixed wing at higher elevations, which fits most of my own flying conditions. Keep up your exceptional work! - Jim
Perfectly demonstrated! How do you think the linear antenna would go at higher altitude say on a plane? I've never actually tried the test other than really close up many years ago and obviously any turn would cause video issues
Great video It is the genuine information you provide that is so worthwhile. You're not saying don't use linear, but you are proving there are real advantages for if and when circular polarisation becomes an option for the individual. Awesome
The 'whoop' style quads nearly all have linear antennas because you can make them so light. I do find it amazing that I can sit in my lounge and fly them all round the house (including all the rooms upstairs) with pretty decent image quality. And that's on just 25 mW, of course.
Is there a particular motherboard or software that makes that little jingle tone when it starts up? My L900 pro does the exact same "do do do.. DEEE" sound when it is turned on.
Is there a better antenna than Aomway cloverleaf? They seem to be hard to beat. I have my antenna mounted about 35 ft off the ground . I need a good long range antenna with 360° reception. I will not be flying above 400 ft. Are right above my ground station. . giving you a hint of the radiation pattern I am looking for. With My 4 leaf Aomway antenna on my RX and TX and 600 w transmitter I have been out to 1.80 MI. at that distance reception is snowy but still visible. I don't want to use a patch on my receiver cuz for one thing it's 35 ft in the air and too hard to change when I want to fly in a different directions. Thanks for any of your advice..
Linear polarity will perform better when you're not flying around parking lots and buildings, etc. Fly around a field with just grass and trees, you'll get less reflection/multipath. However, the point missed here is that the "linear" polarity of an antenna changes as the angle of the quad changes. Linear polarity doesn't work well for a vehicle that does flips and rolls and changes the antennas polarization constantly. Really, that's the true advantage of CP on a quad - circularly polarized antennas - as long as the top and bottom nulls are avoided - never stop being polarized, regardless of angle (aside from the obvious rejection of "some" multipath interference). Using linear polarity on a long range plane, or something that won't tilt as much or as often, provides better results than using CP, where CP's advantages are really lost. Flying "high" in the air, as well, will provide greater range using linear. Obviously, if you're using 5.8 Ghz then you're not really into "long range" or even "mid range" flying. For 5.8 Ghz and doing flippy floppies all over the place, especially in a quad, truly CP is best - but it is good to understand why.
That is an excellent explanation, but there is another factor at play. It has to do with the circular aspect of the polarization and the reflected signals. With linear, all reflections are also linear and an omni antenna picks up the reflected signal just fine.. Ghosting and dropouts.. However with circular polarization, a reflection reversed the polarity EG a LH rotation becomes RH. This can be very clearly demonstrated with a simple optics test. Take polarized sunglasses (linear) and look at yourself in a mirror. Other than attenuation from tinting, you can see your eyes back through the glasses. Pick up a circular polarizer and hold it up to a mirror. Notice anything about the reflection in the mirror? The polarizer will appear completely opaque black in it's reflection. You can't see your eye when looking into a mirror through a circular polarizer. Multi-path in the video signal will do the same to circular polarized reflections. They are rejected at the antenna. Link to example photos of circular polarizers in front of a mirror. www.google.com/imgres?imgurl=http%3A%2F%2Fwww.photonstophotos.net%2FGeneralTopics%2FPolarizing_Filter%2FCircular_versus_Linear_Polarizer_Identification_files%2Fimage001.jpg&imgrefurl=http%3A%2F%2Fwww.photonstophotos.net%2FGeneralTopics%2FPolarizing_Filter%2FCircular_versus_Linear_Polarizer_Identification.htm&docid=s-wUNqlCtja5rM&tbnid=wwWSOjiH2Wix0M%3A&vet=10ahUKEwie0KLup4_fAhUT7J8KHWASCJkQMwiEASgpMCk..i&w=755&h=755&bih=958&biw=1920&q=viewing%20circular%20polarizer%20in%20mirror&ved=0ahUKEwie0KLup4_fAhUT7J8KHWASCJkQMwiEASgpMCk&iact=mrc&uact=8
@@isettech Correct, which is why in parenthesis in my comment, I said, "aside from the obvious rejection of "some" multipath interference". CP rejects multipath interference, but in my experience, not 100%, but definitely a lot - and linear polarity rejects none.
Can a circular polarized 5.8 ghz antenna be used for data let's say 5ghz radio running OpenHD or would I be better to ruber duck ok on plane and flat patch antenna on tracker ?
Very good, it surpassed everything I've seen so far, congratulations. You don't have an electrical diagram for me to put some RF transistors in a vtx to increase its range.
So in the case of a micro or whoop, where a dipole is necasary for weight and space, what's the best setup for antennas to use on goggles? I have a menace linear patch as one of mine but for the second antenna is it still best to use CP antenna on goggles and what yeilds best results, cloverleaf or pagoda? Would using 2 CP antennas be better than 1 CP + 1 patch.?
With CP on goggles and LP on quad, you will have 3dB (or as a ratio, ½) loss due to the polarization mismatch. However, you don't get the issue of cross polarization where you lose a ton of the signal (this is when the antennas become perpendicular instead of collinear). My small quads have linear and I like the results I get from using circularly polarized antennas on my goggles. I use 2 omnis with my RapidFIRE, but if you plan to fly pretty far in one direction, using a patch makes sense. I don't know if a Pagoda or a cloverleaf is better in this instance, though. I usually use pagodas on my goggles for the really good axial ratio, but I wouldn't be surprised if a cloverleaf with slightly higher gain was a little better in some circumstances.
@@redfoxdude ....thanks for the well articulated reply. I have been playing around with different combinations of antennas on my goggles also in different orientations. For my whoops , I currently use 2 CP but both facing up. I haven't tried placing them 90deg offset. I mostly fly my whoops in my basement which is quite large but also all concrete exterior walls. There seems to be a lot of flicker in the video feed in my basement compared to flying outdoors. I have found that my patch offers no real benefit indoors. I'll keep playing around with it. Thanks again.
Looking forward to your next test. Bye the way could send the rain to upper hunter NSW Australia. No feed for the cattle. Question please what would a good small drone to start with. Regards, Gavin.
Hi what about when you flying a small quad with a linear antenna do i need to change to linear on the goggles..or will it be ok with just running the circulars still..so linear to circular
This is a really good question! You will have 3dB (or as a ratio, ½) loss due to the polarization mismatch. However, you don't get the issue of cross polarization where you lose a ton of the signal (this is when the antennas become perpendicular instead of collinear). My small quads have linear and I like the results I get from using circularly polarized antennas on my goggles. Yeah, it's less range theoretically than a linear antenna, but with the way I fly, the TX antenna doesn't constantly stay upright, so cross polarization kills the performance of linears on the goggles for me.
I dont get it... everyone gets a great signal at long distances. I get snow after 50m .... I thing my reciver module is broken. Whats the best diversity fatshark module at the time ?
if you are running GPS, ensure the antennas are as far apart as possible, and there is a quaility, narrow skirt bandpass filter on your video transmitter. Otherwise the 1.3GHz transmitter will desense/overload the GPS receiver. I'd advise staying away from 1.3GHz especially anywhere, even remotely close to airports, as their landing systems operate in the same range.
Bruce does this hold true for your radio as well circular polarization better performance or no because it is digital? I would think less dropped packets equals a more reliable connection for digital radios. Curious why nobody is using this on their radio transmitters and receivers would love to be enlightened.
I did get indoctrinated to use the CP antennas by watching videos. My interest is in knowing why transmitters are most always linear antenna. Is it because the receivers always have a linear wire antenna as well? I've not seen a receiver with a circular antenna attached. Is 2.4 less picky maybe?
I hope you will do a video on which antennas to use in a ground-based rc car fpv setup at some point in time. Perhaps get yourself a cheap rc car and fit an fpv setup on it and test it with various fpv-antennaes to see which antennae is best for range and signal in a fpv setup that is very close to the ground.
And from what I can tell this is a "worst" case scenario. Lollipop has poor axial ratio and radiates in LHCP as well as RHCP. Pretty much any pagoda is better for proximity flying and would make the difference much more clear cut. Looking forward to the long range test. I suspect CP will still help when reaching fresnel zones but as we all know, we're seeing a resurgence of LP antennas for long range fliers and people are having great success with them.
@@cookie4524 I've never had a really close look. All I know is from my own experience and from other You tubers, it's a poor performer compared to the Axii. Still works fine, but it's just an Antenna.
i get rubbish reception what ever i use , my latest set up is the best ive had so far using the Tbs triumph antenna and the tbs vtx running at 500Mw im getting good penetration and range now
Hey Bruce, maybe you can make a video how you disasamble all the linear antennas you have and show to people what they get for free, almost none of those antennas are cut to the right leight for 5.8g.
i think your key statement was, "fly what youve got".. circ. is better of course, but in the end, just get out there and fly what youve got.. too many people wait till they've got all the gear and forget to just get out there and have a crack.. thanks for the vids bruce :)
On my wings I use linear dipole on vtx. I get more range and cleaner signal. Found out by accident. Took first flights with vtx Mmcx dipole as I had no other choices. When my circular came in I took a flight and was expecting a big improvement….wrong. Put the linear back on.
I always use linear on my micros sub 60grs. But I replace the sleeved dipole with a half wave dipole for less weight, also seem to get better video range and quality. Paired with a homemade bi-quad and 25mw tx I’m getting 900meters. I’m using 13mm too, I get the best performance with 13mm.
Im really glad you made this video, the difference isnt that big at close to medium range, although i would be interested to test this same test but with the quadcopter doing rolls and other tricks that would reduce the overlap area between the two antennas
@RCModelReviews Hey Bruce, some 20 months later, I have been flying my quads on those cheap little HGLRC 65mm 5.8G 2dBi U.FL IPEX IPX Omni Directional Linear Brass FPV Antenna's from Banggood, on my quads, with the stock antenna's from my Aomway goggles, and have found them to be really really effective. Apart from not getting smashed off in a crash or at least being a little more resilient to impact, I find they produce really good results when flying amongst the trees. I'd be interested to see if you thought the same.
Your Last Questions , this is what I am really interested in. Because Black sheep used in the olden days Linear Antennas for Long-range Flight, with Yagi 2.4ghz and a linear whip Antenna on the Aircraft. And I saw never other guys using those Antennas.
And what about linear vtx with circular vtx? Is it better than linear-linear? It is winter in the north and we are flying little machines with linear antennas. What should I use in the goggles?
This is a really good question! You will have 3dB (or as a ratio, ½) loss due to the polarization mismatch. However, you don't get the issue of cross polarization where you lose a ton of the signal (this is when the antennas become perpendicular instead of collinear). My small quads have linear and I like the results I get from using circularly polarized antennas on my goggles. Yeah, it's less range theoretically than a linear antenna, but with the way I fly, the TX antenna doesn't constantly stay upright, so cross polarization kills the performance of linears on the goggles for me.
I personally build all my antennas dipole, patch, biquad, and circular polarized. "Even tun them to the exact channel / frequency" I use, and I'm kind of sad that there was not a dipole comparison... "never the less I have actually in the past fly with the cheap linear included on the package and they do ok..
Thank you for posting this video, it's just what I was wondering about. I have a question regarding cave exploration with a flying drone. how far in a cave can a signal work? second question, I'm entering into a cave that was made by water that flows in the winter time, yet by late spring there's about one foot to a foot and a half of room at the entrance bottom of the cave floor and the ceiling. I'm wondering what small drone with a camera and lights are made for something that may be able to hit the ceiling and fall into water, float upright itself and take off again your guidance is very much appreciated. I'm not very experienced with drones. I will be attempting this late April or May of 2019. I'm thinking I need a drone that can float and has some kind of a roll bar to keep the blades from hitting the ceiling. perhaps even make it immediately upright itself with the roll bar so the Drone may be able to take flight again.
With the newer receivers, namely TBS fusion, RapidFire and the likes, multi pathing is way less relevant anymore as it’s handled in the receiver firmware. Right now I’m getting better results with linear antennas than I did with the most expensive CP ones. Still testing though :)
Nice comparison test and I sort of thought in advance the circular ant would work a little better. Your next test I think might just prove the opposite. The circular antenna up high will be great up to a certain distance, but I guess the linear antenna will be able to cover a little more distance. It will be fun to see what results your test will bring. Happy Flying
Try some very steep banks at distance. With LP you lose an enormous amount when one is vertical and the other horizontal. That's the main reason for CP where relative orientation does not matter. The nulls straight up/down are the same for both.
I have a 14dbi patch antenna from hubsan that I bought for my h502s a while back and I now have it mounted on my sjrg01 goggles cause I fly with 25mw and I need more gain for range , but dose anyone or YOU , know how this antenna is polarized ? I’m not sure it looks to be linear but I’m just learning this stuff . I also use a triple feed pagoda on the other sma connector , I also fly brushed micros with dipole antennas so I’m assuming linear is good for dipole ?
H502S does not hhave great range, I only ever got about 500 M with it. But I have had the best range with an Aomway double biquad on the TX with the standard dipole on the quad. I got double the range with a double biquad as apose to the hubsan patch on my 501.
So, while I do listen to the "pros" and seasoned flyers. As I have just started a few months ago. I always try out stuff for myself. I've come to learn that certain antenna work in certain situations better than others. That said when I first bought my goggles all I had was linear so that's what I flew for awhile actually. So if I'm just flying close to me with not many obstructions I put linears on so in case I crash I don't break a better more expensive antenna. Thanks for the info though my friend
My goggles came with a CP mushroom antenna but my RTF quad (QX65) has a built-in linear one. Should I change the goggles ant to linear in order to match the quad? What is the expected loss or problem if the two types of antenna are mixed? Video TX using linear polarization and video RX using CP...
Coming to the video, was wondering: what is a "linear antenna" I know what a linear amplifier is? why not call it a monopole/ half dipole / etc. - need to demonstrate omni-circular polarisation with high gain - loaded - monopole antennas (vertical polarisation). - obviously avoiding, cross polarisation and wi-fi / garage door opener, interference is a good thing) General comment, a vertical-ly polarised antenna gives cross polarisation dropout when an aircraft banks or pitches a whole lot ( not so noticeable flying quads, most of the time) or the radio signal is being reflected off things, but then circularly polarised antenna signals can reverse direction when reflected - can be good ( limiting multipath interference) or bad (if the reflected signal is all you can receive).. Don't forget that one can also make (directional) circular polarisation with crossed dipoles (involving phaseshift)
Interesting first test. TBH I just match antenna types and polarisation. so if the quad/plane comes with linear I put linear on my goggles. Range/quality isn't usually a problem with either unless I'm using FPV trucks
Cool Bruce... these is very valuable information, making a decision on this very topic right now,... so glad had the foresight to subscribe with a bell.... Cheers.
Also you fly fairly upright. What about when doing rolls, hard bank turns, flips and other more acrobatic moves? Linear should get even worse as the gain and radiation pattern work against you the more out of alignment the antennas get.
Man id kill for your linear reception i have makerfare goggles come with circular with the yellow band and a 5.8 patch 12 gain i believe and ts832 600mw powered directly off 3s stock stick the older one with 32 channels runcam skyview i didn't bother getting antennas cause i expected video like you showed it only goes about 200 ft before impossible to see
I don't know why everybody says 5.8 is the best convenient it's cheap. it sucks you have to trial and error a ton of antennas just to get a freaking single.you have to run more power. I'm just wondering why lower frequency isn't the norm. 5.8 for fpv is not very convenient. I guess the availability is. That's it though. You definitely have to buy more stuff for it
@@tymoteuszkazubski2755 what about 1.3ghz? Doesn't seem so bad. the antenna isn't so big. I think my reciever just sucks its a stock fatshark dominator v3 5.8ghz single antenna reciever with the blue lcd display . I have a cheep eachine rotg01 reciever that has way better range.
@@prrcpor as i understand it 900 and 1.3 can cause loss of range and bleed over in certain circumstances... (from what I have been told) and also in 1.3.. to answer some above questions.. 1.3 doesn't allow as many pilots in the air at the same time.. (racing for example) but if you fly L.D. or have no friends it's a very viable option!
@@TheRealMichaelAndrettiyeah but if your flying 1.3 and everyone else is flying 5.8 would u interfere? I'm fairly new to this. I've learned how to build racing drones and just learning fpv flying. I'm at the point where I'm just wishing for better range. Video quality on dominator v3s are fine. It's just man I can't go more then a football field of range without getting snow and everything Else.
Also no I don't have any friends who do this drone stuff.lol. I'm from the north east. U. S. They thinks it's really cool but any offer to get into the hobby is like no way. After doing this for a while I think that most either fear the complexity, time, or expence. Me I've always been into building cars, electronics. Drones - perfect!
Fixed wing you will not notice the distance at all, especially a long distances. Its easier to get a high quality linear patch (such as the Aomway Diamond, a double biquad) then a circular patch. And that really wasn't a fair comparison because those were cheap probably poorly tuned rubber duckies, verses a precisely tuned antenna and a very circular antenna. What you said about the cheapness applies to the duckies as well
I note that a lot of youtubers fly tiny whoops and micros with linear antennas on the craft but keen their cp antennas on their goggles, I would think that that would cause issues.
Please do this again but with proper dipoles. by that I mean real 1/2 wave and or 5/8 wave dipoles,not those base fed monopoles ;) . That would realy show the difference.
I'm here again, and loving it ♡ why is it not tuesday today! sigh, but it feels close :-) thanks a lot this was really educational. I guess if you get used to the linear antennas and the flickers and then upgrade, then your used to thinking far ahead while flying, wich is a good thing. I will have to upgrade, but not before I get some real goggles, and ditch my beginner box.
I wouldn't go as far to say "much, much better" with those results and under those conditions. They were pretty damn close to universally consider the linear trash right out of the box.
I have always used the "junk" stock LP on the aircraft and one LP and a CP on my googles. Works well for me, but I never fly 1km out. I have had fail safe even on the L9R in town though. Then again, I have just tolerated the occasional flicker and momentary loss.
Massive subject mate. You only do proximity flying in this video Bruce so your question is not correct for this video. It should be ‘Which is better when proximity flying?’ I do a lot of non proximity flying and the CP definitely suffers more at range. Looking forward to the follow up video.
@@semihk09 my personal experience i would start having drop outs part few hundred meters and nothing past 800m even with fairly high power transmitters.. But gear has changed now so it may be more achievable these days
@@andygaras I gave the wrong information. I'm sorry. I have no flight experience yet. I'm just trying to make sure I'm starting with the right components as I'm just starting out. I am planning to use 25mW VTX. I guess it is illegal to use 200 mW in my country. I'm thinking of using a 5.8 GHz RHCP TX antenna2.5 dBi (like Foxeer Lollipop) and 10 dBi 5.8 GHz 5-turn RHCP helical antenna on the ground. I don't know if VRX is the right choice, but for now, I have RC832, I plan to watch the video on my computer. I think it will be inevitable for my output power to weaken with the extra connectors I will use due to incompatibilities. Do you think these antennas will be enough for 1-1.5 km range? Alternatively, I can think of using more powerful antennas or diversity controllers?
When I first began FPV I started with linear antennas. And I was flying slow and wobbly and lingered in the nulls... But now imagine my first cloverleaf at 720Mhz (@10ish mW) but I could fly for dozens of meters on a pocket TV as vRX!! :))
I’ve always been disappointed with CP antennas on my quads. I fly mostly in lightly wooded areas, so I suppose there’s not much multipathing going on because there’s hardly any difference between linear whip antennas in terms of performance but a lot of difference when comparing price and durability! Always CP on my goggles by the way.
i dont think you answered the question korrekt.. You testet only with a non linear antenna on the quad but tinywhopps or Tothlpicks use Linear antennas and there the Linear "could?Should?" be better
Without the diversity receiver the linear polarized antennas would be even worse with cross polarization fade. Circularly polarized antennas, not suffering that particular problem, don't benefit as much from a diversity receiver.
During the test you're flying too low to the ground, which implies a lot of reflections. But if someone flies plane, high above ground ? You can conclude that it's bad for quads only.
Have you seen IBCrazy’s Switchblade design, you slip the cap over those linear antennas and it makes them circularly polarised. www.getfpv.com/vas-switchblade-5-8ghz-rhcp-lhcp-hot-swap-antenna.html
I should make a video compilation of every time that Bruce has tossed a linear antenna.
I've done plenty of flying with linear antennas, being on a small budget they go ok. Cheap 200mw tx with supplied antenna, cheap box goggles with supplied antenna and it's still good enough to fly out about 1km at 30mt with a home built fixed wing. You don't need to be all cashed up to have a good time :).
When you race the linear will manke you crash on the gates!
You are wright. For sure people will have a good time flying fpv on linear antennas anyway. And when they upgrade to circular polarized antennas, they will have an even better time :-)
San Pol....Wrong, using a Skew gives a 3 dbi loss....Thats a loss in range over Linear....We dont all fly Mini Quads.
@@EnglishTurbines I understand what you said, we are just talking informally that is possible having a good time on linear, and generally speaking, when you use circular polarized antennas you improve the quality of your reception in most of the cases.
But, in some cases, of course linear can do even better.
@@EnglishTurbines I run a 600mW Tx on a RHCP Pagoda in all of mine. Two cars, one plane. The cars? One's nitro, one's electric. The plane? A NexSTAR 46 with a Magnum 52RFS on the nose. I have no problems whatsoever with signal quality on any of these rigs except when the cars go behind trees.
just returning to the hobby after a year or so, glad to see you still making high quality informative videos as always
Wats the best antenna for inside?
Hey Bruce great video,. How do you get those ugle horizontal lines out of your video
I'd guess gain db or see if it gets better closer u are then it's a mw problem
Maybe this may help
ruclips.net/video/Bx7gMUw1MGw/видео.html
Bruce:
Nice job. I'm not sure I perceived as great a difference and you concluded, but I really appreciate your objectivity in test design, and I'm very anxious for your followup using fixed wing at higher elevations, which fits most of my own flying conditions. Keep up your exceptional work! - Jim
Perfectly demonstrated! How do you think the linear antenna would go at higher altitude say on a plane? I've never actually tried the test other than really close up many years ago and obviously any turn would cause video issues
Great video
It is the genuine information you provide that is so worthwhile. You're not saying don't use linear, but you are proving there are real advantages for if and when circular polarisation becomes an option for the individual. Awesome
The 'whoop' style quads nearly all have linear antennas because you can make them so light. I do find it amazing that I can sit in my lounge and fly them all round the house (including all the rooms upstairs) with pretty decent image quality. And that's on just 25 mW, of course.
agreed, but these are now just as light. www.getfpv.com/fpv/antennas/lumenier-micro-axii-shorty-u-fl-5-8ghz-antenna-rhcp.html
Tinywhoops are the greatest invention of the 21st century
@@icantflyfpv4835 but thy're 20 bucks! Each! 😉
Is there a particular motherboard or software that makes that little jingle tone when it starts up? My L900 pro does the exact same "do do do.. DEEE" sound when it is turned on.
Is there a better antenna than Aomway cloverleaf? They seem to be hard to beat. I have my antenna mounted about 35 ft off the ground . I need a good long range antenna with 360° reception. I will not be flying above 400 ft. Are right above my ground station. . giving you a hint of the radiation pattern I am looking for. With My 4 leaf Aomway antenna on my RX and TX and 600 w transmitter I have been out to 1.80 MI. at that distance reception is snowy but still visible. I don't want to use a patch on my receiver cuz for one thing it's 35 ft in the air and too hard to change when I want to fly in a different directions. Thanks for any of your advice..
So if you have say a Mobula 7 with the little standard whip antenna you would use a dipole antenna for best results ?
Linear polarity will perform better when you're not flying around parking lots and buildings, etc. Fly around a field with just grass and trees, you'll get less reflection/multipath. However, the point missed here is that the "linear" polarity of an antenna changes as the angle of the quad changes. Linear polarity doesn't work well for a vehicle that does flips and rolls and changes the antennas polarization constantly. Really, that's the true advantage of CP on a quad - circularly polarized antennas - as long as the top and bottom nulls are avoided - never stop being polarized, regardless of angle (aside from the obvious rejection of "some" multipath interference). Using linear polarity on a long range plane, or something that won't tilt as much or as often, provides better results than using CP, where CP's advantages are really lost. Flying "high" in the air, as well, will provide greater range using linear. Obviously, if you're using 5.8 Ghz then you're not really into "long range" or even "mid range" flying. For 5.8 Ghz and doing flippy floppies all over the place, especially in a quad, truly CP is best - but it is good to understand why.
That is an excellent explanation, but there is another factor at play. It has to do with the circular aspect of the polarization and the reflected signals. With linear, all reflections are also linear and an omni antenna picks up the reflected signal just fine.. Ghosting and dropouts.. However with circular polarization, a reflection reversed the polarity EG a LH rotation becomes RH. This can be very clearly demonstrated with a simple optics test.
Take polarized sunglasses (linear) and look at yourself in a mirror. Other than attenuation from tinting, you can see your eyes back through the glasses. Pick up a circular polarizer and hold it up to a mirror. Notice anything about the reflection in the mirror? The polarizer will appear completely opaque black in it's reflection. You can't see your eye when looking into a mirror through a circular polarizer.
Multi-path in the video signal will do the same to circular polarized reflections. They are rejected at the antenna. Link to example photos of circular polarizers in front of a mirror. www.google.com/imgres?imgurl=http%3A%2F%2Fwww.photonstophotos.net%2FGeneralTopics%2FPolarizing_Filter%2FCircular_versus_Linear_Polarizer_Identification_files%2Fimage001.jpg&imgrefurl=http%3A%2F%2Fwww.photonstophotos.net%2FGeneralTopics%2FPolarizing_Filter%2FCircular_versus_Linear_Polarizer_Identification.htm&docid=s-wUNqlCtja5rM&tbnid=wwWSOjiH2Wix0M%3A&vet=10ahUKEwie0KLup4_fAhUT7J8KHWASCJkQMwiEASgpMCk..i&w=755&h=755&bih=958&biw=1920&q=viewing%20circular%20polarizer%20in%20mirror&ved=0ahUKEwie0KLup4_fAhUT7J8KHWASCJkQMwiEASgpMCk&iact=mrc&uact=8
@@isettech Correct, which is why in parenthesis in my comment, I said, "aside from the obvious rejection of "some" multipath interference". CP rejects multipath interference, but in my experience, not 100%, but definitely a lot - and linear polarity rejects none.
Do you think an RHCP 3 dBi medium quality antenna would work, usually vertically, at a range of 1-1.5 km towards the air?
Can a circular polarized 5.8 ghz antenna be used for data let's say 5ghz radio running OpenHD or would I be better to ruber duck ok on plane and flat patch antenna on tracker ?
Simple and well illustrated demonstration. Thanks Bruce. I'm now one of your Patreons NTW.
Great review! and the side by side video really helps to understand the difference for those undecided..:)
Very good, it surpassed everything I've seen so far, congratulations. You don't have an electrical diagram for me to put some RF transistors in a vtx to increase its range.
So in the case of a micro or whoop, where a dipole is necasary for weight and space, what's the best setup for antennas to use on goggles? I have a menace linear patch as one of mine but for the second antenna is it still best to use CP antenna on goggles and what yeilds best results, cloverleaf or pagoda? Would using 2 CP antennas be better than 1 CP + 1 patch.?
With CP on goggles and LP on quad, you will have 3dB (or as a ratio, ½) loss due to the polarization mismatch.
However, you don't get the issue of cross polarization where you lose a ton of the signal (this is when the antennas become perpendicular instead of collinear).
My small quads have linear and I like the results I get from using circularly polarized antennas on my goggles. I use 2 omnis with my RapidFIRE, but if you plan to fly pretty far in one direction, using a patch makes sense.
I don't know if a Pagoda or a cloverleaf is better in this instance, though. I usually use pagodas on my goggles for the really good axial ratio, but I wouldn't be surprised if a cloverleaf with slightly higher gain was a little better in some circumstances.
@@redfoxdude ....thanks for the well articulated reply. I have been playing around with different combinations of antennas on my goggles also in different orientations. For my whoops , I currently use 2 CP but both facing up. I haven't tried placing them 90deg offset. I mostly fly my whoops in my basement which is quite large but also all concrete exterior walls. There seems to be a lot of flicker in the video feed in my basement compared to flying outdoors. I have found that my patch offers no real benefit indoors. I'll keep playing around with it. Thanks again.
Thanks for all the work you do making your videos, I have learned alot from your channel!
Sir if i use LHCP antena on quad and RHCP on goggle will there be huge breakupd signal loss
Correct, so stop doing it.
Hi Bruce, when is the longer distance video coming that you mention at the end! Been waiting a while ;)
Was there a part 2?
Looking forward to your next test.
Bye the way could send the rain to upper hunter NSW Australia.
No feed for the cattle.
Question please what would a good small drone to start with.
Regards,
Gavin.
Great comparison test, Bruce - love a proper side-by-side. I'm curious as to what's inside the lollipop - skew planar?
Hi what about when you flying a small quad with a linear antenna do i need to change to linear on the goggles..or will it be ok with just running the circulars still..so linear to circular
This is a really good question! You will have 3dB (or as a ratio, ½) loss due to the polarization mismatch.
However, you don't get the issue of cross polarization where you lose a ton of the signal (this is when the antennas become perpendicular instead of collinear).
My small quads have linear and I like the results I get from using circularly polarized antennas on my goggles.
Yeah, it's less range theoretically than a linear antenna, but with the way I fly, the TX antenna doesn't constantly stay upright, so cross polarization kills the performance of linears on the goggles for me.
@@redfoxdude thank you so much for explaining this to me.. I have been wondering and wondering about just this exact subject!!!
I dont get it... everyone gets a great signal at long distances. I get snow after 50m .... I thing my reciver module is broken.
Whats the best diversity fatshark module at the time ?
The RapidFIRE is pretty popular and performs pretty incredibly. I love mine, and the newer firmware with goggle OSD is awesome.
What about rc cars the controller 2.4ghz I need distance without lot of interface will one of these round antennas do the job
You know I always wondered about the linear antennas on the transmitters. Would you benefit by putting a CP on your taranis?
I'd be curious to see the same test on fixed wing running the 1.3ghz band for video.
if you are running GPS, ensure the antennas are as far apart as possible, and there is a quaility, narrow skirt bandpass filter on your video transmitter. Otherwise the 1.3GHz transmitter will desense/overload the GPS receiver.
I'd advise staying away from 1.3GHz especially anywhere, even remotely close to airports, as their landing systems operate in the same range.
good evidence and great video Bruce
looking forward to the higher flying results
Bruce does this hold true for your radio as well circular polarization better performance or no because it is digital? I would think less dropped packets equals a more reliable connection for digital radios. Curious why nobody is using this on their radio transmitters and receivers would love to be enlightened.
What kind of DVR was used to record this video? Picture looks quite good!
I did get indoctrinated to use the CP antennas by watching videos. My interest is in knowing why transmitters are most always linear antenna. Is it because the receivers always have a linear wire antenna as well? I've not seen a receiver with a circular antenna attached. Is 2.4 less picky maybe?
hi HaveFaithInGod, have you become a flat earther yet?
I hope you will do a video on which antennas to use in a ground-based rc car fpv setup at some point in time. Perhaps get yourself a cheap rc car and fit an fpv setup on it and test it with various fpv-antennaes to see which antennae is best for range and signal in a fpv setup that is very close to the ground.
And from what I can tell this is a "worst" case scenario. Lollipop has poor axial ratio and radiates in LHCP as well as RHCP. Pretty much any pagoda is better for proximity flying and would make the difference much more clear cut. Looking forward to the long range test. I suspect CP will still help when reaching fresnel zones but as we all know, we're seeing a resurgence of LP antennas for long range fliers and people are having great success with them.
The '2' version is just a trash cloverleaf and radiates like you say, the '1' was an Axii clone.
@@SickocrowAU the 2 is not a clover leaf, it works in the same style as the axii. its parts are made of laser cut copper rather than pcb though
@@cookie4524 I've never had a really close look. All I know is from my own experience and from other You tubers, it's a poor performer compared to the Axii. Still works fine, but it's just an Antenna.
i get rubbish reception what ever i use , my latest set up is the best ive had so far using the Tbs triumph antenna and the tbs vtx running at 500Mw im getting good penetration and range now
The video by truerc showing the axial ratio of the new axii micro showed that the lollipop had pretty bad axial ratio
I rock a linear whip @ 600mW on quad, and circular pagoda + circular patch on goggles. Works out for a nice balance between range and quad weight
You should test linear on the VTX and circular on the VRC for model weight savings
Hey Bruce, maybe you can make a video how you disasamble all the linear antennas you have and show to people what they get for free, almost none of those antennas are cut to the right leight for 5.8g.
i think your key statement was, "fly what youve got".. circ. is better of course, but in the end, just get out there and fly what youve got.. too many people wait till they've got all the gear and forget to just get out there and have a crack.. thanks for the vids bruce :)
On my wings I use linear dipole on vtx. I get more range and cleaner signal. Found out by accident. Took first flights with vtx Mmcx dipole as I had no other choices. When my circular came in I took a flight and was expecting a big improvement….wrong. Put the linear back on.
do Linear Antennas have RHCP or LHCP ?
no, they have vertical or horizontal ( or in betwixt) polarisation.
I use linear all the time..even on my Quads...On Fixed Wing a RD and a vertically polarised Patch pair beats the pants off any skew.
The thumbnail got me interested i was like what kind of alien fpv system is this
I always use linear on my micros sub 60grs. But I replace the sleeved dipole with a half wave dipole for less weight, also seem to get better video range and quality. Paired with a homemade bi-quad and 25mw tx I’m getting 900meters. I’m using 13mm too, I get the best performance with 13mm.
Learnt a lot thanks mate 👍
Im really glad you made this video, the difference isnt that big at close to medium range, although i would be interested to test this same test but with the quadcopter doing rolls and other tricks that would reduce the overlap area between the two antennas
Anecdotally, the FarVew Pagoda V2 antennae made a huge difference in my FPV setup compared to the linear polarized ones that came with my setup.
@RCModelReviews
Hey Bruce, some 20 months later, I have been flying my quads on those cheap little HGLRC 65mm 5.8G 2dBi U.FL IPEX IPX Omni Directional Linear Brass FPV Antenna's from Banggood, on my quads, with the stock antenna's from my Aomway goggles, and have found them to be really really effective.
Apart from not getting smashed off in a crash or at least being a little more resilient to impact, I find they produce really good results when flying amongst the trees.
I'd be interested to see if you thought the same.
Do you think an RHCP 3 dBi medium quality antenna would work, usually vertically, at a range of 1-1.5 km towards the air?
Your Last Questions , this is what I am really interested in.
Because Black sheep used in the olden days Linear Antennas for Long-range Flight, with Yagi 2.4ghz and a linear whip Antenna on the Aircraft.
And I saw never other guys using those Antennas.
a vee and a biquad is a great combo. linear also works better at lower frequencies too
And what about linear vtx with circular vtx? Is it better than linear-linear?
It is winter in the north and we are flying little machines with linear antennas. What should I use in the goggles?
This is a really good question! You will have 3dB (or as a ratio, ½) loss due to the polarization mismatch.
However, you don't get the issue of cross polarization where you lose a ton of the signal (this is when the antennas become perpendicular instead of collinear).
My small quads have linear and I like the results I get from using circularly polarized antennas on my goggles.
Yeah, it's less range theoretically than a linear antenna, but with the way I fly, the TX antenna doesn't constantly stay upright, so cross polarization kills the performance of linears on the goggles for me.
Great side by side video. More of this on format please.
I personally build all my antennas dipole, patch, biquad, and circular polarized. "Even tun them to the exact channel / frequency" I use, and I'm kind of sad that there was not a dipole comparison... "never the less I have actually in the past fly with the cheap linear included on the package and they do ok..
Thank you for posting this video, it's just what I was wondering about. I have a question regarding cave exploration with a flying drone. how far in a cave can a signal work? second question, I'm entering into a cave that was made by water that flows in the winter time, yet by late spring there's about one foot to a foot and a half of room at the entrance bottom of the cave floor and the ceiling. I'm wondering what small drone with a camera and lights are made for something that may be able to hit the ceiling and fall into water, float upright itself and take off again your guidance is very much appreciated. I'm not very experienced with drones. I will be attempting this late April or May of 2019. I'm thinking I need a drone that can float and has some kind of a roll bar to keep the blades from hitting the ceiling. perhaps even make it immediately upright itself with the roll bar so the Drone may be able to take flight again.
With the newer receivers, namely TBS fusion, RapidFire and the likes, multi pathing is way less relevant anymore as it’s handled in the receiver firmware. Right now I’m getting better results with linear antennas than I did with the most expensive CP ones. Still testing though :)
Nice comparison test and I sort of thought in advance the circular ant would work a little better. Your next test I think might just prove
the opposite. The circular antenna up high will be great up to a certain distance, but I guess the linear antenna will be
able to cover a little more distance. It will be fun to see what results your test will bring. Happy Flying
great video, Bruce!!! thanks
Have always used linear antenna on my fixed wing. 600mW VTX with 20 dBi plate antenna on receiver is good for 30+ km.
Please test with 1.2g
Try some very steep banks at distance. With LP you lose an enormous amount when one is vertical and the other horizontal. That's the main reason for CP where relative orientation does not matter. The nulls straight up/down are the same for both.
I can go miles on a linear whip TX antenna and Yagi rx antenna.
Yes, there is an improvement of about x2 of the circular over the linear; but not that great IMO.
I have a 14dbi patch antenna from hubsan that I bought for my h502s a while back and I now have it mounted on my sjrg01 goggles cause I fly with 25mw and I need more gain for range , but dose anyone or YOU , know how this antenna is polarized ? I’m not sure it looks to be linear but I’m just learning this stuff . I also use a triple feed pagoda on the other sma connector , I also fly brushed micros with dipole antennas so I’m assuming linear is good for dipole ?
H502S does not hhave great range, I only ever got about 500 M with it. But I have had the best range with an Aomway double biquad on the TX with the standard dipole on the quad. I got double the range with a double biquad as apose to the hubsan patch on my 501.
So, while I do listen to the "pros" and seasoned flyers. As I have just started a few months ago. I always try out stuff for myself. I've come to learn that certain antenna work in certain situations better than others. That said when I first bought my goggles all I had was linear so that's what I flew for awhile actually. So if I'm just flying close to me with not many obstructions I put linears on so in case I crash I don't break a better more expensive antenna. Thanks for the info though my friend
My goggles came with a CP mushroom antenna but my RTF quad (QX65) has a built-in linear one. Should I change the goggles ant to linear in order to match the quad? What is the expected loss or problem if the two types of antenna are mixed? Video TX using linear polarization and video RX using CP...
Coming to the video, was wondering: what is a "linear antenna" I know what a linear amplifier is? why not call it a monopole/ half dipole / etc. - need to demonstrate omni-circular polarisation with high gain - loaded - monopole antennas (vertical polarisation). - obviously avoiding, cross polarisation and wi-fi / garage door opener, interference is a good thing)
General comment, a vertical-ly polarised antenna gives cross polarisation dropout when an aircraft banks or pitches a whole lot ( not so noticeable flying quads, most of the time) or the radio signal is being reflected off things, but then circularly polarised antenna signals can reverse direction when reflected - can be good ( limiting multipath interference) or bad (if the reflected signal is all you can receive)..
Don't forget that one can also make (directional) circular polarisation with crossed dipoles (involving phaseshift)
Interesting first test. TBH I just match antenna types and polarisation. so if the quad/plane comes with linear I put linear on my goggles. Range/quality isn't usually a problem with either unless I'm using FPV trucks
Cool Video. Awaiting next one. :)
Cool Bruce... these is very valuable information, making a decision on this very topic right now,... so glad had the foresight to subscribe with a bell.... Cheers.
Also you fly fairly upright. What about when doing rolls, hard bank turns, flips and other more acrobatic moves?
Linear should get even worse as the gain and radiation pattern work against you the more out of alignment the antennas get.
Man id kill for your linear reception i have makerfare goggles come with circular with the yellow band and a 5.8 patch 12 gain i believe and ts832 600mw powered directly off 3s stock stick the older one with 32 channels runcam skyview i didn't bother getting antennas cause i expected video like you showed it only goes about 200 ft before impossible to see
I don't know why everybody says 5.8 is the best convenient it's cheap. it sucks you have to trial and error a ton of antennas just to get a freaking single.you have to run more power. I'm just wondering why lower frequency isn't the norm. 5.8 for fpv is not very convenient. I guess the availability is. That's it though. You definitely have to buy more stuff for it
@@tymoteuszkazubski2755 what about 1.3ghz? Doesn't seem so bad. the antenna isn't so big. I think my reciever just sucks its a stock fatshark dominator v3 5.8ghz single antenna reciever with the blue lcd display . I have a cheep eachine rotg01 reciever that has way better range.
@@tymoteuszkazubski2755 what if u use crossfire 900 mhz for controle and 1.3ghz for
@@prrcpor as i understand it 900 and 1.3 can cause loss of range and bleed over in certain circumstances... (from what I have been told) and also in 1.3.. to answer some above questions.. 1.3 doesn't allow as many pilots in the air at the same time.. (racing for example) but if you fly L.D. or have no friends it's a very viable option!
@@TheRealMichaelAndrettiyeah but if your flying 1.3 and everyone else is flying 5.8 would u interfere? I'm fairly new to this. I've learned how to build racing drones and just learning fpv flying. I'm at the point where I'm just wishing for better range. Video quality on dominator v3s are fine. It's just man I can't go more then a football field of range without getting snow and everything Else.
Also no I don't have any friends who do this drone stuff.lol. I'm from the north east. U. S. They thinks it's really cool but any offer to get into the hobby is like no way. After doing this for a while I think that most either fear the complexity, time, or expence. Me I've always been into building cars, electronics. Drones - perfect!
Wait is this xjet because u sound like him
My Qx65 tinywhoop is my comfy quad lol. I'm still deathly afraid to fly the 5" I built. Thing is a rocket.
Fixed wing you will not notice the distance at all, especially a long distances. Its easier to get a high quality linear patch (such as the Aomway Diamond, a double biquad) then a circular patch. And that really wasn't a fair comparison because those were cheap probably poorly tuned rubber duckies, verses a precisely tuned antenna and a very circular antenna. What you said about the cheapness applies to the duckies as well
Thanks Bruce!
I've never been more concerned about the weather in your country. Looking forward to your tests.... ;)
How about now?
I note that a lot of youtubers fly tiny whoops and micros with linear antennas on the craft but keen their cp antennas on their goggles, I would think that that would cause issues.
Please do this again but with proper dipoles. by that I mean real 1/2 wave and or 5/8 wave dipoles,not those base fed monopoles ;) . That would realy show the difference.
I'm here again, and loving it ♡ why is it not tuesday today! sigh, but it feels close :-) thanks a lot this was really educational. I guess if you get used to the linear antennas and the flickers and then upgrade, then your used to thinking far ahead while flying, wich is a good thing. I will have to upgrade, but not before I get some real goggles, and ditch my beginner box.
I wouldn't go as far to say "much, much better" with those results and under those conditions. They were pretty damn close to universally consider the linear trash right out of the box.
I have always used the "junk" stock LP on the aircraft and one LP and a CP on my googles. Works well for me, but I never fly 1km out. I have had fail safe even on the L9R in town though. Then again, I have just tolerated the occasional flicker and momentary loss.
3 dB polarization loss going from linear to circular polarized, but as a constant that doesn't change as you bank the aircraft.
@@hanelyp1 I use the CP for better coverage in the nulls such as overhead.
Winter starts here I want spring right now :(
I hear that. I just flew 5 battery's after work. I feel like I'm chasing the sun
Thank you. Great video
Massive subject mate. You only do proximity flying in this video Bruce so your question is not correct for this video. It should be ‘Which is better when proximity flying?’ I do a lot of non proximity flying and the CP definitely suffers more at range. Looking forward to the follow up video.
I've found better range with linear+patch antennas than CP antenna. For fairly upright flying anyway
Do you think an RHCP 3 dBi medium quality antenna would work, usually vertically, at a range of 1-1.5 km towards the air
@@semihk09 my personal experience i would start having drop outs part few hundred meters and nothing past 800m even with fairly high power transmitters.. But gear has changed now so it may be more achievable these days
@@andygaras I gave the wrong information. I'm sorry. I have no flight experience yet. I'm just trying to make sure I'm starting with the right components as I'm just starting out. I am planning to use 25mW VTX. I guess it is illegal to use 200 mW in my country. I'm thinking of using a 5.8 GHz RHCP TX antenna2.5 dBi (like Foxeer Lollipop) and 10 dBi 5.8 GHz 5-turn RHCP helical antenna on the ground. I don't know if VRX is the right choice, but for now, I have RC832, I plan to watch the video on my computer. I think it will be inevitable for my output power to weaken with the extra connectors I will use due to incompatibilities. Do you think these antennas will be enough for 1-1.5 km range? Alternatively, I can think of using more powerful antennas or diversity controllers?
Interesting practice test Bruce, Strathmore Park! I thought that looked like today's thunderstorm....Rgds Laurie
Super test and yes the rain is bad for FPV
When I first began FPV I started with linear antennas.
And I was flying slow and wobbly and lingered in the nulls...
But now imagine my first cloverleaf at 720Mhz (@10ish mW) but I could fly for dozens of meters on a pocket TV as vRX!! :))
I’ve always been disappointed with CP antennas on my quads. I fly mostly in lightly wooded areas, so I suppose there’s not much multipathing going on because there’s hardly any difference between linear whip antennas in terms of performance but a lot of difference when comparing price and durability! Always CP on my goggles by the way.
We pay homage to the great RC Guru, You Sir.
i dont think you answered the question korrekt.. You testet only with a non linear antenna on the quad but tinywhopps or Tothlpicks use Linear antennas and there the Linear "could?Should?" be better
Bruce , a lot of work involved in doing that test , even though i don't fly FPV thank you . Don't fly TOOOOOOO high on the next test :-)
Without the diversity receiver the linear polarized antennas would be even worse with cross polarization fade. Circularly polarized antennas, not suffering that particular problem, don't benefit as much from a diversity receiver.
Really? w)w I had NO idea.. thanks!!!
During the test you're flying too low to the ground, which implies a lot of reflections. But if someone flies plane, high above ground ?
You can conclude that it's bad for quads only.
Have you seen IBCrazy’s Switchblade design, you slip the cap over those linear antennas and it makes them circularly polarised.
www.getfpv.com/vas-switchblade-5-8ghz-rhcp-lhcp-hot-swap-antenna.html
The Hangars will screw the linear test...IMO Bruce.
2:30 that analogy was perfect 😂 what a guy!
Stu, you know the radiation patterns, what are you doing to yourself. Lol