2LikesTransmitter latency - does it really matter?
08-29-2012, 06:05 AM
#31
I think there was an letter I read just before 2.4 came on the market that it would take some time for the 2.4 to have even or less latency than standard RF at the time. If I'm right, 2.4 still has a higher latency than standard RF.
08-29-2012, 06:08 AM
#32
QUOTE=M3Armand;11147323
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 do.
.
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 do.
.
Last edited by Tim3; 08-29-2012 at 07:01 AM.
08-29-2012, 06:11 AM
#33
\
I have seen testing results on one of the el-crappo cheapfest radios that revealed some startling bad numbers. Not only could the delay be as much as .06 seconds, but it varied anywhere from .02 to .06 seemingly at random. Now tell me, if you're a pro running one inch from the board at every apex and someone hands you a radio with that kind of variance, do you really think you can keep it off those boards while running the same tight lines and laptimes? I sure couldn't. If you want to see those results, dig through the radio sub forum, it's in there somewhere.
I have seen testing results on one of the el-crappo cheapfest radios that revealed some startling bad numbers. Not only could the delay be as much as .06 seconds, but it varied anywhere from .02 to .06 seemingly at random. Now tell me, if you're a pro running one inch from the board at every apex and someone hands you a radio with that kind of variance, do you really think you can keep it off those boards while running the same tight lines and laptimes? I sure couldn't. If you want to see those results, dig through the radio sub forum, it's in there somewhere.
08-29-2012, 09:47 AM
#34
I got a Futaba handset and Spektrum modules as soon as I could 'what, no more crystal changes, wow, I'm sold'
But the latest high end handsets are so fast it's insane.
Skiddins
08-29-2012, 12:20 PM
#35
08-29-2012, 12:37 PM
#36
In on-road it is really obvious, running 27mhz crystals I was fine close to boards. Then before the main I had to switch as channels were full so I ran first gen specktrum, after the race everyone was asking me why I was turning in so much later than I was in quals and I wondered why my car would not run tight lines
08-29-2012, 02:35 PM
#37
Tech Apprentice
when i return back to rc racing after having five years off racing karts, i started using a 2.4 etronic rc transmitter and i couldn't get the hang of it and i couldn't work it out why i was finding my car so hard to drive, it was like i wasn't connected to the car.
during my time off i would still visit my local club and borrow a car for the night and still putting in a good race, so i new it wasn't me.
I got to boiling point with it all and thought there's one left to try, a different set of radio gear, so i borrow a old sanwa gemmi 2 and i was on the money straight away.
next day i order a sanwa exzes and haven't looked back, only wish i brought this when i started back instead messing about with the cheap 2.4 equipment and wondering why i couldn't clip apex' and understeer into corners and have to wait to long when coming out of corners to get back on the throttle.
during my time off i would still visit my local club and borrow a car for the night and still putting in a good race, so i new it wasn't me.
I got to boiling point with it all and thought there's one left to try, a different set of radio gear, so i borrow a old sanwa gemmi 2 and i was on the money straight away.
next day i order a sanwa exzes and haven't looked back, only wish i brought this when i started back instead messing about with the cheap 2.4 equipment and wondering why i couldn't clip apex' and understeer into corners and have to wait to long when coming out of corners to get back on the throttle.
08-29-2012, 02:57 PM
#38
Going from Futaba 3PM-FS to a Sanwa MT-4, I noticed better driving feel not only on steering, but also throttle and braking.
08-29-2012, 03:07 PM
#39
I'm still using a 27MHz FM KO Vantage Esprit II. One of the things that has scared me off going to 2.4GHz is the latency issue.
A quick web search will tell you that the average human reaction time is 150 to 300ms. So, if your radio has a 15-30ms latency that is like increasing your reaction time by 10% every time. Latency is going to be less of an issue when running on a track by yourself – your turn in point just comes up a little earlier, but when racing other cars that sometimes do things you don't expect this is an issue. It's also an issue on a bumpy offroad track where you have to react to what the car is doing more.
Remember too, that 150 to 300ms is the average human reaction time. It's been shown that competing in a sport like RC racing probably improves your reaction time – it certainly delays the onset of slowed reaction time with age according to one study. And the top guys are going to be better than the average.
It's not inconceivable that a 40ms latency is actually increasing a person's effective reaction time by 50%.
A quick web search will tell you that the average human reaction time is 150 to 300ms. So, if your radio has a 15-30ms latency that is like increasing your reaction time by 10% every time. Latency is going to be less of an issue when running on a track by yourself – your turn in point just comes up a little earlier, but when racing other cars that sometimes do things you don't expect this is an issue. It's also an issue on a bumpy offroad track where you have to react to what the car is doing more.
Remember too, that 150 to 300ms is the average human reaction time. It's been shown that competing in a sport like RC racing probably improves your reaction time – it certainly delays the onset of slowed reaction time with age according to one study. And the top guys are going to be better than the average.
It's not inconceivable that a 40ms latency is actually increasing a person's effective reaction time by 50%.
08-29-2012, 03:19 PM
#40
Tech Addict
iTrader: (38)
I believe latency is something you will just get used to, just like how fast your servo is or how reactive the steering on your car is. Putting more grip on the front, a faster servo or less latency will likely cause you to hit the same board in the same way but over time YOU will adjust. The most important thing a radio needs to do is feel right in your hands. If the controls are awkward or don't feel right, the amount of latency won't matter one bit.
08-29-2012, 04:29 PM
#41
I'm still using a 27MHz FM KO Vantage Esprit II. One of the things that has scared me off going to 2.4GHz is the latency issue.
A quick web search will tell you that the average human reaction time is 150 to 300ms. So, if your radio has a 15-30ms latency that is like increasing your reaction time by 10% every time. Latency is going to be less of an issue when running on a track by yourself – your turn in point just comes up a little earlier, but when racing other cars that sometimes do things you don't expect this is an issue. It's also an issue on a bumpy offroad track where you have to react to what the car is doing more.
Remember too, that 150 to 300ms is the average human reaction time. It's been shown that competing in a sport like RC racing probably improves your reaction time – it certainly delays the onset of slowed reaction time with age according to one study. And the top guys are going to be better than the average.
It's not inconceivable that a 40ms latency is actually increasing a person's effective reaction time by 50%.
A quick web search will tell you that the average human reaction time is 150 to 300ms. So, if your radio has a 15-30ms latency that is like increasing your reaction time by 10% every time. Latency is going to be less of an issue when running on a track by yourself – your turn in point just comes up a little earlier, but when racing other cars that sometimes do things you don't expect this is an issue. It's also an issue on a bumpy offroad track where you have to react to what the car is doing more.
Remember too, that 150 to 300ms is the average human reaction time. It's been shown that competing in a sport like RC racing probably improves your reaction time – it certainly delays the onset of slowed reaction time with age according to one study. And the top guys are going to be better than the average.
It's not inconceivable that a 40ms latency is actually increasing a person's effective reaction time by 50%.
Now, I'm not sure what the latency of my mouse is, but typically I'm getting between 230 and 280ms. The thing is after doing it for a while, you think I nailed that trial or that was a bit slow, and then you look at the score and there is only 30ms difference between the two.
Try it for yourself.
08-29-2012, 04:47 PM
#42
I found this reaction time tester online: http://www.flashscience.com/biology/reaction_time.htm
Now, I'm not sure what the latency of my mouse is, but typically I'm getting between 230 and 280ms. The thing is after doing it for a while, you think I nailed that trial or that was a bit slow, and then you look at the score and there is only 30ms difference between the two.
Try it for yourself.
Now, I'm not sure what the latency of my mouse is, but typically I'm getting between 230 and 280ms. The thing is after doing it for a while, you think I nailed that trial or that was a bit slow, and then you look at the score and there is only 30ms difference between the two.
Try it for yourself.
Interestingly you mentioned mouse latency. So I started out using the spacebar instead of the mouse. Then tried the wireless mouse and was routinely about 30ms QUICKER. It seems my keyboard has more latency than the wireless mouse
08-29-2012, 05:04 PM
#43
Pretty cool. One I felt I really nailed was 234ms. Then one popped up really quick and caught me off guard. That one I felt like I had totally blown and it was 260ms. It seems the brain has no problem noticing 26ms.
Interestingly you mentioned mouse latency. So I started out using the spacebar instead of the mouse. Then tried the wireless mouse and was routinely about 30ms QUICKER. It seems my keyboard has more latency than the wireless mouse
Interestingly you mentioned mouse latency. So I started out using the spacebar instead of the mouse. Then tried the wireless mouse and was routinely about 30ms QUICKER. It seems my keyboard has more latency than the wireless mouse
I just did a quick calculation too. If you are travelling at 36 km/h (22 mph) – which is about the speed of a quick spec class on the straight – then in 15 ms you will travel 15 cm (half a foot). Every ms latency is 1 cm on track at that speed (every 2.5 ms is 1 inch). That can make a difference in avoiding an accident.
08-29-2012, 05:07 PM
#44
On my airtronics m11, latency is only noticeable when the battey voltage gets too low. FWIW, when I first switched over from spektrum to airtronics, difference was night and day. I feel much more "connected" with airtronics.
08-29-2012, 06:09 PM
#45
it does matter
I have a KO ex-1ur with ko 27mhz, 72mhz module and a 2.4G module from flysky GTB-3 and a Sanwa m-11x with 2.5ms latency receiver and fhss-2 receiver(older model and slower)
I tried it on VRCPRO. frame rate for 27,72 mhz is around 122f/s .sanwa 2.4g is almost equal , maybe 1 to 3 frame less. KO with with GTB-3 is around 55.
For the latency variation, I don't notice any big difference .
For signal drift. Sanwa is little better than KO.
On track performance : KO fm . I consistently make best lap with KO fm.
the car feel more connected , more agile and I can change driving line easier and drive closer to the apex. Sanwa with 2 differenct receivers, I don"t really notice any difference between them. Although I feel it is not as fast as KO. The performance is still good and somehowI drive more consistent with it.
Flysky module .(22ms latency).the car wont turn , undrivable.
I tried 3 times on different day and the result is the same.
I tried to eliminate the performance different cause by 2 diffent radio. so I tried to match the spring tensions , steering wheel angle of those 2 system. epa. It made a big difference. but I still feell O fm perform better.
I did another test with different servos(Sanwa srg-cr(shr capable), ko 949, savox 1250 (shr ok), futaba s9551) fm is the fastest ,2.4 is slower. I can tell just by watching the servo move.
Finaly test: real track perfomance somehow is not as dramatic as on VRCPRO.
conclusion. For sure,there is speed diffecnce. The tighter the track and higher speed, the bigger difference it make.
(pls note:most of the world top drivers already changed to high speed 2.4G so in real world the performance is more than adequate.)
I tried it on VRCPRO. frame rate for 27,72 mhz is around 122f/s .sanwa 2.4g is almost equal , maybe 1 to 3 frame less. KO with with GTB-3 is around 55.
For the latency variation, I don't notice any big difference .
For signal drift. Sanwa is little better than KO.
On track performance : KO fm . I consistently make best lap with KO fm.
the car feel more connected , more agile and I can change driving line easier and drive closer to the apex. Sanwa with 2 differenct receivers, I don"t really notice any difference between them. Although I feel it is not as fast as KO. The performance is still good and somehowI drive more consistent with it.
Flysky module .(22ms latency).the car wont turn , undrivable.
I tried 3 times on different day and the result is the same.
I tried to eliminate the performance different cause by 2 diffent radio. so I tried to match the spring tensions , steering wheel angle of those 2 system. epa. It made a big difference. but I still feell O fm perform better.
I did another test with different servos(Sanwa srg-cr(shr capable), ko 949, savox 1250 (shr ok), futaba s9551) fm is the fastest ,2.4 is slower. I can tell just by watching the servo move.
Finaly test: real track perfomance somehow is not as dramatic as on VRCPRO.
conclusion. For sure,there is speed diffecnce. The tighter the track and higher speed, the bigger difference it make.
(pls note:most of the world top drivers already changed to high speed 2.4G so in real world the performance is more than adequate.)