Range Test FrSky RX | WRONG ANTENNA LENGTH? 

There is a misconception in the RC community that receiver antenna length is critical. It is not. I believe this misconception results from the fact that transmitter antennas ARE length critical. One of the reasons for this misconception is that people read on the internet about tuning transmitter antennas, and assume it applies to receiver antennas as well. The actual science is quite involved, very math intensive, so few delve deep into it. Here's my attempt to explain what I know of it in a easy to understand framework. I hope it helps out. Transmitter antennas radiate a certain portion of the power fed to them, and reflect the balance back to the transmitter - this is why operating a transmitter with the wrong or without an antenna can damage it, nearly all the power is reflected back to the output transistor and it overheats. Some of the power is transmitted and some is reflected back to the transmitter. This forms a ratio. This ratio is known as the Standing Wave Ratio (SWR) which is a ratio of power sent to the antenna (forward) vs the power radiated by the antenna (1:1 being ideal - where all the power is radiated). SWR is determined by measuring the power being reflected back from the antenna and comparing it to the power being sent to the antenna (Reverse : Forward). An example would be a system with a SWR of 1.2:1 and a transmitter power of 1200mw. 1000mw will be radiated, and 200mw is returned to the transmitter and generates heat. If the antenna is tuned perfectly, with a 1:1 SWR, all 1200mw will be transmitted. This is a compromise on tunable systems, as the antenna is tuned for a specific length, and is only perfect (or nearly so) at one specific frequency. This antenna tuning can be achieved by cutting the antenna to a resonant length, but can also be done by matching it to the antenna with a inductor/capacitor network. Known in HAM circles as a “Transmatch” this network allows a single antenna to be used with a very wide range of transmitted frequencies and provides very good performance. It uses variable inductors and capacitors and is re-tuned for each desired frequency. A small specific version of this network (with fixed components) is often integrated into small transmitters to make them work better with less than perfect antennas. This is a simplification for the sake of brevity (like I warned about) and any time a a signal 'changes hands' some of it is as accepted and some reflected (which is why I went into all that detail above). This is all about matching impedances, and that's a big subject, worthy of entire books. Here's why it matters: In any case, on a receiver antenna, the only concern it that it draws the signals you want from the air as efficiently as possible. In doing so, it draws in virtually all radio signals, with the length determining which are best received. THIS is why we care about the length of a receiver antenna. It's a broad range, not a specific channel, or even a band (such as they are with our 5.8ghz video signals), covering many MHz. We finally get to why the length matters: The receiver uses a series of tuned circuits to eliminate the unwanted adjacent signals, and focus on the desired channels. The 1st stage of this process occurs where the antenna meets the receiver (IE “front end”). To remove the bulk of the unwanted radio energy, the receiver works with the antenna to create an impedance mismatch at frequencies above and below the desired target. This forms a broad tuned circuit, and reflects a large portion of the unwanted signals back to the antenna, where it is re-radiated (disposed of). The desired signal is thus 'pre-cleaned' allowing more sophisticated circuit to further refine it. The antenna plays as part of this tuned circuit, and contributes it's capacitance and inductance (components of impedance) the the components in the receiver circuitry. It's length effects it's impedance, and how it interacts with the receiver. This is WHY antennas will vary in length on different receivers, and why it helps, but is NOT critical to have them 'just right'. Each receiver has it's own specific front end impedance, and wants a antenna that works with it to produce the best performance. I apologize for the length of this comment, and have to qualify that I had to simplify some details to keep it this size, so don't beat me up if there's some minor inaccuracy or imprecision in it somewhere. I tried to make the basic principles easy to understand, and hope it helps out.

Thank you for taking the time to do these types of tests. I don't currently run FrSky, but its nice to know that you have done the actual work behind figuring this out and might help in the future if I go to FrSky. Great video as always!

Your testing is very very appreciated, you have spent hours making tests that not anyone can easily do. Thanks Joshua Greetings from Italy

Thank you Josh, we all appreciate the time and effort you put into all of your videos. I watch them regularly and look forward to new ones just because I know I am going to learn something :) I know most people might question why you do some of these videos, but I wish I had the time and knowledge you did on the subject because I wonder these things often but am unsure how to answer them. Thank you for putting into words some of the answers we wonder when no one is looking :)

In the last 30 minutes between watching your video and reading the comments I've learned more about antennas then I've ever wanted to know. People use to pay for this type of information! Thanks for your time in all the work that you do to promote the hobby and teach everyone about the facts you've uncovered.

Ive been wondering about this for a while. Thanks for doing this test!

If I remember, Stingy and Steele did a test, and found that using the 31mm on the XSR gave the best results over the stock antenna.

Thank you for this great test. I know it took a whole bunch of time to prepare and analyse everything, but in the end we got a quite good answer!

this question mark had been on my mind for a long time until just now. great video!

I asked about this maybe a year ago when you posted the FrSky antenna mod. This explanation was a bit more in depth. Thanks. :)

Great info JBard, thanks for doing the hard science and getting us this tasty tasty data!

like always, I appreciate the time and sound science. Well done and 'I did learn something'. keep them coming.

Hi Joshua, again a very cool video from you. I have to thank you for all your content, which made me learn a lot! This time I think I can give you some informations: To get the best reception from an existing combination of components, the length of the antenna-"core" (unshielded part) needs to be perfekt for a combination of: actual wave-speed, frequenz, antennas environment, ... I would advise you to: put the TX far away ... if you like in your car ... and you stay at your quad. Yes I saied quad, because of the antennas environment! you want it to work in you quad, so tune it there ! As someone in the comments already saied, your ground-part (which is also the carbon of your frame) of the antenna and anything in its neighborhood will change its behavior. So use the place where it will have to work. The only thing you should change during the tuning is the length of the antenna. You changed the distance and as you have seen in your chart, you got hills and valleys. I'm shure this was because of interferences. You got bounced signals on from what ever which de- or increased you signal. Don't use several recievers, there can be so much different ( quality of rf-chip, antenna-matching, groundarea ...) Also, the recievers working next to each other can change there behavior. So put the TX in the car far away, go into the house with your quad and your goggles ( need to see rssi in the osd !). Put the quad somewhere where it can't move, but it should sit on something similar to air, because your quad normaly is in the air ... I usally use styrofoam, this has nearly no effect on the resonance and matching. Use only one of the antenna cables, disconnect the other. To get great range of frequency in your test, use a antenna with a very long core. measure the antennacore-length, step back from the quad, read the RSSI ... put values into chart .. cut a little piece of the antenna, as small as possible (I like to use a fingernail clipper) measure the antennacore-length, step back , read the RSSI ... put values into chart .. cut a little piece . . . everything should be the same, even your position while reading the RSSI You will get a nice graph! greetings, Max

I like the way you explain things. It makes it easy to understand.

Love this sort of testing. Thanks Joshua

Great vid JB, an interesting watch. Perfect for the lunch break. Eating and learning. Win win!

Excellent. Thanks for your time and efforts! You are the best!!

Alex knows his stuff; be been keeping up with him 6 years now for his antenneas.i use blue beam exclusively.Thank u for this video I like your approach.

HI, What a nice test, love it. I think the way of your test is fantastic. And especially the energy that you put into it. But I always thought that the antenna length of the transmitter was more critical. I may see that wrong. Again, love your approach and the way you attack a Challenge!

Thanks for the great video Mr. Bardwell.

Good test Josh , keep doing these vids .

I'm never disappointed with your Videos!

I was looking forward to seeing this video. Great

Wow that's a test rig! Amazing effort mate. Thanks.

Great testing Joshua! I'm a young RF enthousiast, and I have access to a network analyzer that goes up to 3GHz. I was thinking, since all these antennas have U.FL connectors, I can just hook one up to the VNA and see at what frequency it resonates. The resonant frequency of these antennas are dependent on the length of the exposed antenna wire (outside of the coax) but the size and location of the RF ground will also be important for antenna tuning. One thing that is also interesting to note, is that the receiver chips cannot do any antenna tuning, the only option is that they put passive components at the feedpoint of the antenna, to change the antenna impedance. However, any time you are tuning an antenna with inductors or capacitors, the components MUST be right before the radiating side of the antenna. You cannot really tune an antenna at the feedpoint of the coax cable, since the 50-ohm coax will transform the impedance, which is dependant on the coax length. I think I'm going to try to hook up my VNA to one of these 'whip' antennas, and I also want to see if I can see any matching components on the PCB. The best test to measure the antenna resonant frequency would be to use hot air to remove the RF chip on the receiver, and solder a tiny coax cable directly on the pads where the signal to the antenna goes. Then you can perform a calibration, and actually measure the impedance that the chip is 'seeing' with all the RF ground and matching components on the PCB.

I think I'll do a video on this but basically there are many factors that influence those antennas and it's not just "tuning" but also radiation pattern, impedance and other things which determine how the antenna will actually perform. Joshua's test environment had too many variables to get consistent and therefore accurate results so I'll try to come up with something that mitigates (as far as possible) those variables. It's an interesting subject and one that's worth more discussion. I'll try to get my vid done tomorrow.

Thank you for going out and spearmint. it's people like you that we learn from thank you

Thank you for the wicked analogy about radio frequency vs actual frequency of updates we throw out into the airways. helped me understand the tuning a hint more.

12 and a half minutes into the video and I think you gave me the answer to my range issues. Thank you.. I think..😉👍

Had to jump back in time... I placed an R-xsr in my newest build for Lua and such, problem is I failsafed in a spot that I had no issues with my other build using Xm+. I noticed the length of the R-xsr antenna. It is much shorter. So I ordered some after market antennas to test. Thank you for this video! Seems to explain why this crash happened.. ScooterPie

thanks for going through with this, i tried to grasp this stuff right when i started flying toys, using 3/4 length transmitter and half wavelength receivers... its a really complex topic to even try and reduce to laymans terms,. iforce2d had very similar outcomes to you with flysky set ups, using the 26mm and the 28mm? sleeved dipole version versus a strict 31.125mm.. he said if anything the stock antennae were the best, he tested in open countryside with actual return to home quads. so all we can do is go with the manufacturers choices, they seem to know best....

Hey JB. Good to see that somebody, atleast ;), tries to get some reliable data out of this. After everybody was going crazy for the 5dbi mod and it's range extension, I did some tests on my own using the Taranis logging. Unfortunately the results between 2dbi and 5dbi where so close that you couldnt tell a difference in just range - and until now, no one seem to investigate it and providing detailed data like in this test. You seem to stick to the stock antenna with your x9D SE, but maybe there will be a science-like-validation by you at some point. Always appreciate your content and way to present and explain stuff!

Nice tests! How ever, I'm a ham radio operator and I once had a chat with an engineer who said "Don't bother with the antenna. Design the apparatus and match the antenna after." Antenna is irrelevant at these frequencies (With in limits) The matching is crucial. Keep up the great work, buddy!!

Jb another info spectacular! Thx

Learnt loads. Many thanks. Ray

Same experience here... I have 3 XSRs and experimented with different antenna lengths. Bone stock seems to work best and better than my two X4R SBs. I have two R-XSRs sitting on my bench for new builds - lets see how this goes.

You know you’re doing good work when Martin Baert gets in on the comments section. Great work and an awesome video!

Don't forget that these receivers transmit (sending RSSI data) as well as receive, so undoubtedly the manufacture will have tuned the antenna length to match the RF output stage, this will usually give a length that is not a factor of wavelength, for example a capacitive output they will have needed to lengthen the antenna and if inductive shorten it.For receive only the length is nominally the same as for transmit and a general rule of thumb for receive only is usually 95% of the wavelength. The antenna length is best left as the manufacturer / designer set it.

great video brother

very informative! thank you!

I hate to admit it, but my new favorite go-to receiver is the XSR-E (the Banggood Eachine/Frsky collaboration). It's damn near the same size as an XM+, but has telemetry. Also, according to my sketchy/not quite Bardwell-quality field testing, it performs almost identical to my old go-to X4R SB's. I have the XSR-E's on 7-8 models right now, and they're performing great!

A great video! With 20:20 hindsight you should have included two identical receiver/antenna combinations to compare their differences with the differences between different receivers and antennae. That's just me being a smartass after the event.

You need more distance to see the real results. Stinger swarm did this same test on RotorRiot and his results were inconclusive due to his cat chewing his antennas haha. But from what I can see is that even in Range mode, you need a lot more distance then you have in your yard to get any solid results from the data, they were in a pretty big field. Maybe you could use a dummy load to cut down the range? I was thinking of doing the same test on a dry lake bed here in California, but have since switched to Crossfire, so there is no need. Great video, very informative!

Very interesting results. Somewhat counterintuitive to preconceptions. Either way, great data to have.

So for now... buy what you like and use that till more testing is completed. Got it. Thanks Jb

Any time I have ever chopped or messed up an antenna, or as soon as I get a new antenna, I always measure it myself. It’s simple, use this formula to expose the proper amount of the inner wire. 300 divided by your radio frequency, then divide that by 4 to give you a 1/4 wave length. I typically try to use 2.44. This hits in the middle of the frequency and seems to work best for me. I’ve seen so many ppl who do not peel back the coating, and mesh to expose the inner wire and they think its a bad receiver when its simply not peeled back.

Thank you, nice work

Nice test. I’m interested in when the FC sees a failsafe based on range. It would be nice to have a FC logging to blackbox RSSI values and when a Failsafe occurs. Add a beeper for the fun of it and you walk until and audible tells you a failsafe took place and put a flag in the ground.

Question: I’m confused as to how some of these transmitter modules allow for more range. For example, the TBS Crossfire. This is for for transmitting/receiver range? If so, how does your video transmission keep up with such distance with a crossfire? My video feed always cuts out before my transmitting range, so how would the VTX signal keep up with the receiving signal when using a Crossfire?

In my company we design and test antennas as a part of daily development. You are certainly right that the tune of the antenna comes not only from conductor length. Type of surrounding materials, including the "plastic" shroud, distance to all objects in near field (first wavelength), and antenna material itself can all affect how well the antena is tuned to certain frequencies, heck - even the quality of solder joints can. The tune itself is not a 0/1 factor. There are all possible shades of gray between optimal tune to a frequency and ignoring it all together. Moreover you can have a decently tuned antenna using certain fractions of a wavelength physical size. I'd assume that manufacturers test and use the right combination of length and materials to get desired results. To do those tests right you'd need to use only one receiver, cause differences between them can be too big to see changes made by the antenna, and be very precise with physical distance and orientation between tested devices, avoid multi path transmission as much as possible etc. Short story - You are right, but you'd probably see something consistent only in an anechoic chamber.

I used to work in an office next door to an rf guy. He tuned his antennas by connecting them to am rf network analyzer, holding his tongue a little to the left, and then with his side cutters, cut a few molecules off the end of the wire.

As a layman I conclude two things from these tests. 1: the engineers at FrSky seem to know what they're doing when they design these antennas and receivers. 2: no matter which receiver you get, unless you're going for super long range or something, you're going to have a very solid reliable signal. I was slightly concerned when I bought the R-Xsr that it may have less range than a full size receiver, but it seems I was worried for nothing!

8:13 fu#$% you touched my heart there joshua haha nicest self advertising ever all the way!! I just bought 2 parallel chargers from your brand, and also i am thi king in patreon you, bjt first i have to understnd how does that work, you helped me so much in the hobby ... i trully owe you a beer at least! Thanks for all mate

I just had an image of JB in a cloak and hat like Gandalf, carrying around his staff of FRSKY receivers. "You wouldn't deny an old man his staff, hmm?"

What should the quarter wave length be for 27mhz

What happens if you have two different antenna lengths on the same receiver?

Makes me wonder what is the difference in using numbers in between the 23mm to 33mm. Meaning is there any difference between 23,24,25 and so on or if there are specific number that make the antenna good and just so happens that the 23,26,32 you tested is about there... Great video and its awesome that you put all this thought on questions people have but most dont bother to investigate!!!

Nice test, but maybe should be done on open field with various receivers of each model because there is lot of bad FrSky receivers. Your job is great and I understand the financial limits of that kind of test. I get the best results with R-XSR and redundancy xm+ and changing antennas with replacement ones. I fly more than 2km without any warning. Of course that doesn't mean nothing but it's good for me.

Good test - I was wondering this too. The thing is, that the monopole antennas does not have good VSWR in first place, so a few milimeters does not matter. If you want a good antenna you need a dipole.

Love the Goats, they are notorious RF signal boosters though...

We have similar discussions in our german forums without clear solutions too... One short tip maybe you test it. If i shred a antenna i removed the jacket and then i evert the helical ground wire. Its then like a dipol told me an skilled "antennaguy". Functioned for me but not range tested because the Video Signal was the limited factor.

I am new to the hobby (Loving it by the way), and I am also an active Ham Radio operator. With Radio frequencies, antennas perform the best if they are trimmed for a specific frequency in a band. So for example with the 2-meter band in ham radio (144 to 148 MHz) you would make the antenna 1/4 or 1/2 wavelength to 146 MHz. The antenna will be usable on the whole 2-meter band, but will still be most efficient on 146 MHz, so in the case of FPV, technically those antennas will perform best on whatever frequency (Channel) that the antenna is actually trimmed for. So if you know the frequency you always use you can trim them for it. I enjoy your videos. You sold do similar tests on all of the different channels to find out on which channel each antenna is most resonate. Impedance and radiation pattern also affect it like xjet said. I do think it would be interesting to test them all throughout the band though. I am sure that then each one would perform better on different channels.

I've tested XM+ receiver range with stock 25mm antennas, then with 31mm antennas and last one was much better

Pls assist how many length the best for r xsr? And what the max range could reach wiith this rx?

Good idea for testing this, and thanks for doing it, but the methodology I don't understand. Why cross-test different receivers and different antenna lengths in random associations? It makes it so much more difficult to isolate the effect of the antenna length. I would focus on the receivers where it's easy to get rssi value. For each of those (there is only 3), test 3 different antenna lengths and record rssi for each combination. Then you have 9 curves that you can compare. You can see, for each receiver, which antenna length works best, and you can maybe then see a trend towards one antenna length giving better range in general.

great stuff watched the whole video end to end AND I fly spectrum , very informative great channel thank you even a tech hack like me could appreciate

Hi Joshua! 0:40 I see Betaflight backpack. When can we expect a review of this one? Is it good? I was planning to buy one but would like to get some honest review opinion. thanks!

Dear Joshua, could you please share your taranis transmission power (in range check) and in default mode. Thank you.

Good Test ! They all seem pretty close .......... Have you tried different antennas on One Receiver unit ? ........ or different Transmitter antennas ? Also increasing your height was interesting ........ it would be beneficial to know the optimum height for your TX antenna . Great show !

Thank you Josh, I appreciate your videos and tests. Silly question, have you ever used a rubber coated paper clip for antennae? I have tons of questions actually, I'm wondering what the pitch/gauge of the antenna changes about the signal efficiency as well as wether or not a wispy versus firm antenna matters at all either. :) I want more range for my drone and the vtx without having to double the literal strength and diverting it with anything aftermarket. (who knows, there may be a way with math on our side)

I have very good experience with XM+ stock antennas (almost 1km of solid signal). XSR with stock antennas was much worse (around 700m when it already started giving me alerts). XSR with aftermarket antennas from banggood worked better but still lacking behind the XM+.

My best signal stability and range have come from running a pair of sleeve dipole antennas on my xm+ receivers. Just standard wifi rubber ducky antennas with the housing removed and direct soldered to the Rx. compared to stock antenna lengths, 1/4 wave re-trimmed, or anything else, they perform much more stably. I got the idea from an rcgroups page on testing the taranis range with different antenna setups, and I'll stick with it for my freestyle quads, since they're the only ones that I ever really push the range with anyway.

I never hear the term ground plane , when I was active in CB the ground plane--- rear bumper (very directional) to roof top (best over all).Would the carbon frame act as a ground plane, thus positioning ant. differently affecting the tran. pattern? Have pity on me I went to electronics school 56years ago.

Setup and GPS track flight (in spiral?) and log the RSSI signal of each receiver/antenna er multiple times (3 at least for each combo) XM+ broadcast RSSI in a channel. This setup would give the close to ideal result of a real case use I suppose. Sadly I don't have GPS nor weather to run this test model. Of course it is a massive work that probably wont be performed for obvious/practical reason.

I bought some replacement antennas for my frsky reciever for when I chop them off in a crash - the replacement antennas are longer than stock on two of my recievers..... wondering if it'll be tuned badly for my reciever and if I should snip them...

Question for the group- my AR631 Spektrum receiver was giving me spotty reception, motor would stop & at 100ft normal mode motor and all control surfaces stopped working. I noticed that my antenna seemed shorter than a new store bought version- maybe mine was cut in the many crashes plane has taken- AR631 should be 9" long new. Well, mine is only 3" long and wire at end was not exposed. I cut plastic and shealthing off end about 1 1/4" inch can it greatly improved. Question is, how much range did I loose having only a 3" antenna????? anyone?

Great effort trying to figure this out. With my time spent in CB radio hobby before, my experience is that the antenna length vs range is not that critical for receivers than transmitters. I.e. If you got the a bad antenna, say a wrong length antenna, even using a bare wire cut casually will still receive considerbly good. However the same antenna if used in a transmitter, can have high SWR and thus affect range considerably at the receiver side. Regarding to why the antenna length is different for different receivers, I AM PURELY GUESSING HERE, are they related to the telemetry transmission freq of these receivers? Since these receivers are with telemetry, meaning that these antennas are also used as transmitter antenna, is Frsky use a length that is particularly tuned to the freq(s) used by these different receivers? If that is true, then we should see fixed, say 32mm antenna for all non-telemetry receivers caused they are just for receiving ..... hmmm, looking forward for your further reseach into it.

I was just comparing the replacement antenna to the originals on my R-XSR, replacement is right about 31mm, brand new R-XSR: 23mm...

Is there anyway you can find out if FrSky has tuning circuitry in their receivers? I am an antenna designer and i'm thinking without any tuning these different length antennas should be very similar in efficiency. however if the RX's are turned for specific antenna lengths then putting a different length antenna or also different length feed coax will make much more of a difference in efficiency. it would be cool if you could get FrSky to confirm that or not. From your testing it looks as though there is not any antenna tuning circuitry since most of these antennas seem to test about the same.

Looking at your first graph, would it be right to conclude that a stock XSR is better than an R-XSR reception wise ? The blue line is above the orange line only between 60-80ft. 20ft interval over 120ft total

Nominal Velocity of Propagation is the key to your shorter antenna. Also interesting: Most of these receiver antennas are only a half dipole. So if you measure 1/4 length of unshielded wire it might be actually 1/2 wavelength antenna design but its only half of the antenna present.

So what im thinking now is , if I need to replace my antennas which one do I use then ?

Worth mentioning that an antenna for receiving only is not as critical as an antenna that broadcasts. In a badly adapted antenna, the radio energy will bounce back into the transmitter, and thus the range will decrease. That would be interesting to measure swr on the counterparts with telemetry.

Joshua may i request for a review and range test on the frsky receiver L9R, claimed long range. I use this and fly 2km paired on my frsky XJT module. Would be nice to see a detailed review from you.

Thanks for all the work you put into your videos, but I want to learn more today! I just bought the Kopis 1 (love it) and have a question about mounting the receiver antennas. I was able to squeeze in a spektrum SPM4649T in there, but due to wiring restrictions I ended up with the antennas pointing towards the back from the front arms. You gave directions to mount them pointing to the front from the back arms. Can you tell me if that matters. I can make a longer harness to flip the receiver around if you think there will be an improvement. And could you explain why it matters if they point to the back or front? Please and thank you from an appreciative viewer.

I've been messing with this for awhile after noticing on my xsr the RSSI was fluctuating a lot. So I tried putting new 31.2mm then shortened those antennas to 29.5mm then 26mm. What I noticed was the 29.5mm length for the antenna seemed to have a more stable RSSI then the the other 2 lengths and I have been able to fly in places where normally I would have failsafed. I think it is cause it is about 95% the wave length and copper wire has a velocity factor of about 0.95. My best explanation is that the antenna needs shorter to compensate for the difference in speed between charges in the wire and the radio waves interacting with the wire.

SUGGESTION! How about use one receiver. strip the antenna to a long length (say 4or5mm) walk a range test, then trim 1mm walk the same range test, repeat the test taking 1mm off until the antenna each time record and share the results 😄. P.S. I love your goats 🐐😜

My Futaba receiver is 144 total and 28mm at the end works good

Hey Joshua, I know that its pointless for multirotors to say, but it prooves my point (and fun-fact). Ive stopped trying to find out the range of these guys a long time ago. I gave up :) First one does not support SBUS but "my friend" was flying 3.3km long range with old v8r7-ii. Other friend tried the "real" test, left transmitter at home and went hiking to near mountain - he did nearly 6km when he gave up. (X8R using SBUS). Not mentioning that our EURO version of taranis is on 100mW (not sure if 100 but I know is less then US). I guess these newer guys will stick to that performance.

lol great test Teach i didnt walk lol that seemed like to much time i flew out to a set range but in end found 10% max rssi between lengths. so after a few reads found the modules like to channel switch between 2.4-2.5ghz and used about 81% as VF and cut a test mid frequencies used copper tape and made it a sleeved dipole as well. its a small increase like i can now go behind stuff without warnings i couldn't before but is not like crossfire just more stable on read out and haven't had to hold remote up in fear of failsafe. playing around later i did found use for all them rubberducky antenna now have a set of personal 5.8 helical and other circular polarized antennas that work nice less flicker on my liked channel. also my motors im customizing came out great lol think i have a combo that is unique.

Don't forget the antanna on the drone/plane must also be the same size as the transmitter to get full benafits.

Joshua, thank you for the detailed content. When building a pagoda antenna kit, is there a guide to how short you can make the coax? Thank you in advance.

Great video , I was hoping you would do some penetration testing. We found 1/4 wave seems to go farther in dense trees.

Joshua, the XM+ does have rssi, it broadcasts it on a channel and works wonderfully. I've actually flown the longest distance with an XM+ compared to a stock x4r-sb and xsr. It's too bad you didn't get that in the video but very cool video anyways!

I would like your opinion Joshua. I am having range problems with my XSR receiver. The receiver is new and I have a Taranis X9D Plus. The radio works fine with other receivers, only this one has range problems. How could I improve that? Is that a receiver problem? Tks a lot!

What about influence from ground effect and Fresnel zones? You're quite low over ground...?

I watched Stingy and Steele test this in real flight test. An XSR with 32mm mod outperformed x4R with 32mm stock, which both whooped an xsr with 23mm stock, therefore I run a modded XSR.

That was weird... Maybe test with an otter transmitter. Its like you TX is putting out a higher transmit level in range test mode...

Planning on doing any testing with the TBS Crossfire?

Isn't RSSI sensor in the Taranis? In other words, you limiting the TX power with range test may not affect the output power of the signal transmitted to the Taranis from the receiver. Not sure that makes sense though because your readings did drop more than I would expect for that distance. I've never really paid attention other than on my L9R and that still had 80% RSSI at around 1.5 miles. Just wondering.