Transmitter latency - does it really matter?
 

I'm writing to see if anyone has actually and TRULY felt a speed difference among the various 2.4 GHz transmitters out there. I.e. - Futaba vs. Spectrum vs. Airtronics vs. Traxxas vs. KO Propo, etc....

I'm in the market for a new transmitter... I've been running my "old school" 75Mhz transmitters for the past 2 years since getting back into RC. I've been super happy with my old transmitters since I know how to use them pretty well and am very accustomed to them. However, with me running more and more cars at the track, it's getting to be a pain taking a different transmitter for each of the cars. Note that I've had ZERO glitching issues (since everyone else is on 2.4 GHz!). So the only real gain from me switching to 2.4GHz is that I will be using ONE controller vs. 6.

So now back to the question. The new Airtronics M12 is supposed to be the fastest transmitter out there followed by the Futabas and then Spectrum. I don't know how Traxxas 2.4GHz, KO Propo or any of my old 75MHz transmitter stacks up.

So can anyone actually and TRULY say they felt a difference among the 2.4 GHz transmitters or if they even felt a difference coming from 75 MHz? Again, glitching is not an issue for me. Thanks in advance!

I went from a Futaba 3VC with Spektrum Modules, To a KO Esprit 3 Universe and was almost immediately faster.
I now use a Sanwa Super Exzes X and love it.

I can't say it was definitely the latency that helped me improve, but there was definitely a difference in the end result.
Maybe it was the 'resolution' that the servo and ESC had with the newer receivers that gave better precision.

I sold one of the KO Esprit 3's to a friend and everyone commented about how much quicker he was at his track over using his old handset.

Skiddins

Here's how I look at it.

Radio response times are measured in milliseconds, and servo transit times are measured in hundredths of seconds. So imagine the difference between a fast and slow servo, divide that difference by about 10, and that is the difference you may or may not feel.

Yep Thats the way I see it. Its much more important to make sure you have a good servo.

That's not exactly the same thing. Servo speed is how long it takes the servo to move a certain amount, but it STARTS moving essentially instantly (as far as the test goes). Latency is the delay between when you move a control and when the servo STARTS to move. So no matter how fast your servo is, the delay is ALWAYS there. Also, some of the real crappy radios out there are very inconsistent in their latency. It might be just 10ms one time, and 40ms the next. That's not good for consistent driving.

Fortunately, most of the good radios out there are reasonably quick but KO and Airtronics/Sanwa seem to have a bit of an edge. That being said, I still say my FM M11 feels quicker than ANY 2.4 out there, especially compared to Spektrum which is noticeably less responsive.

who actually publishes the latency to know the difference???

I don't buy that anyone can tell the difference between 10ms and 40ms anyway.

I can. Obviously I don't know the exact numbers of the radios I have used but I have noticed the differences. Spektrum sucked, M8 was very good, M11 was slightly better still.

That being said, I really can't tell much if any difference running dirt. But 1/8th onroad and especially 1/12th, yes it matters.

Want to see the difference of a few ms for yourself? Get a wired Xbox controller and one of those golf games where you have to hit the button at a specific time to hit the shot (or any other game like that). Play it with the wired controller until you have mastered it, then switch to wireless. You will suck at it for a while.

So if my requirements were speed, then I guess I'm better off staying with my old 75 MHz transmitter, huh? I must say, I'm pretty happy with them. Just tired of lugging all the transmitters and having to worry about all of them being charged, etc...

In real cars with automatic "manual transmissions", I can tell the difference between 10 ms and 80 ms.

Wow... great point. But in this case, there's no "servo" actuating the golf swing.

One other point I wanted to make was that the new Airtronics M12 is like $600 with $100 receivers... While I'm a darn good driver, I DO NOT have any aspirations to go real racing and can justify that price. Turnigy has a 2.4GHz transmitter for $36 with $6 receivers and can accommodate 10 cars... Umm.... that's one heck of a price swing.

So if the KO Propo and Airtronics have that much of a latency advantage, then I'm wondering why don't all the pros run them?

From what I hear, M12s and KOs are quicker but I haven't tried them myself yet.

In onroad, most do.

1/12th IFMAR Worlds:

1 Naoto Matsukura Sanwa M12
2 Andy Moore Sanwa Exzes X
3 Ronald Volker Sanwa M11X
4 Marc Rheinard Sanwa M11X
5 Rick Hohwart Airtronics M11X
6 Simo Ahoniemi Sanwa
7 Alexander Hagberg KO Propo EX-1
8 Jilles Groskamp Sanwa
9 Elliott Harper Sanwa Exzes X
10 Hideo Kitazawa Futaba 4PKSR

Never said that it was the same thing. Only that If you have a slow radio and a slow servo, you should upgrade the servo first. That will make the biggest difference. Then a fast radio will get you a little more response. Thats where I was coming from.

Umm.... WOW... but then why would they bother switching to another radio for the other car classes? Or do they?

I'm sorry I still find it hard to believe. What measurable difference is their? And I dont mean perceived difference...

Running off road you certainly wouldn't notice it. Running onroad doesn't mean you would notice it. You could have a slight push at initial turn in that you see as a lag in steering input. So the radio must be slow.

There is a huge difference between the response of a computer and the response of an RC car on the ground.

We aren't talking about a cars transmission. Apples and oranges. And we certainly aren't talking about the difference between 10ms and 80ms. 10ms and 40ms was what was refereed to. Less than half what you are referring to.

Like I said what radio manufacturer publishes the latency? How do you know what the latency of the radios are?

And just FYI, because a lot of people get bent out of shape when people disagree with them online, this isn't me arguing with you. This is me debating it and wanting proof. I've wondered the same thing. I have a Futaba 4PL. I certainly couldn't justify the price of a 4PKS because "its faster". I'm sure it is faster. But how much? Its like buying a servo that is .09 vs one thats .08 but paying $100 more for the faster one.

And to make it fair I think a person would also have to take the Tx out of the box without making any adjustments other than trim. Because the features of a radio can make a car feel faster around a track lap time wise. And not all radios have the same features.

Simply too many variables to say its the latency as far as I see it.

Slow servos are not always a bad thing. Speed and latency are two different things. Latency is ALWAYS undesirable, servo speed can be a bad thing, a very little difference thing, or a good thing. The slowest servo on earth will still START to move as soon as it gets the signal, so at least the car starts to respond at the same time, regardless of the servo's transit time.

1. A .2 second servo with a 10ms (.01 seconds) latency radio = the car starts to respond in 10ms and reaches full travel .2 seconds later.

2. A .1 second servo with a 40ms radio will actually reach full travel sooner (.140 vs .201) but it will START to move .03 seconds later.

Could you drive a car with an instantaneous servo but a radio with a 2 second delay? I think that would be pretty much impossible. Less latency is ALWAYS better. Of course, the law of diminishing returns come into play in a big way. Yes, 2 second latency would be undriveable but what about .2? You could drive it but would probably hit a lot of stuff. Get down to .05 or so and things seem good to the average guy but .02 would still be better. Is it worth $500 to get down to .01? For most, probably not. That money would be much better spent on tires and track time but if that aspect is already maximized, then it probably is.