I'm new to rc and I'm in the market for my first transmitter that doesn't come with an RTR model. I'm looking at the spektrum dx3s. The only thing I'm not sure of is what exponential and dual rate and all that stuff means. I'm mainly into electric off road but I may grow into on road as well. Any links or explanations about what this terminology means would be great.

Try google for the terms and youtube. There are plenty of videos out there with lots of info. Also when you pick a radio look at the cost of the receivers, some can be rather pricey.

Like I have the futaba 3pl and might go to the 4pl. The receivers can be had for between 40 and 50 dollars.

4PL!!! Your looking for trouble with Spektrums.

What kind of trouble? I am not brand loyal so any input is taken into consideration. I just want everything to go smoothly

some have range issues or glitches. I cured mine, but if I was to buy new today, I would get a MT-4 airtronics....

As far as the number of channels, what else do I need other than throttle and steering? I figured a 3 channel Would be sufficient for what I need but I may be wrong.

Owned an original Spektrum DX3, DX3R, and currently a DX3R Pro. I've NEVER experienced a single glitching issue with any of those radios. I've also never had a range issue either, but I tend to not drive my cars until I can't see them anymore. I'd bet a majority of Spektrum bashers probably never owned one and still insist that they're garbage. There are many great radio choices out there, Spektrum included. Hard to go wrong with any of the mid to upper price range radios. Good luck with your decision.

I'll take a stab at some basic terms....

Dual Rate - Allows you to limit the range of how far the wheels will turn from side to side. Perhaps you want to limit the wheels to only turning a quarter of the way out each way. You would set the dual rate where you want it, and then turning the wheel on the transmitter would only move the wheels within that range. Can be used to adjust over and understeer, or remove steering if your car is too "squirrely" on the track

Exponential - Normally when you turn the wheel or pull the trigger, it responds in a linear fashion. Pulling the trigger 30% of the way back (or turning the wheel) will increase the throttle 30%. Expo allows you to increase the movement exponentially. The more you turn, or pull, the more it increases (it may double every 10% for example - So physically pulling 5% gives you 5% throttle, but physically pulling 10% gives you 20% throttle). Rather than exactly mapping your movements, it increases exponentially. Can be used to build speed quicker and change the throttle feel, or apply even more steering, the more you steer.

EPA - End point adjustments. Lets you limit how far the servo travels in each direction. For example, I race oval. I want the wheels to be able to turn all the way to the left, but not very far to the right. So I limit how far the servo can travel in each direction with EPA. It's different on each side. Gas people use this too, since the physical throttle on the engine can only be pushed so far.

Speed - Allows you to adjust the speed of the servo artificially. You can't go faster than the servo physically allows of course, but you can slow it down. I use this too in oval. I can see drag racers or crawlers using it too. You don't want your wheels jerking in one direction or the other, so you slow it down.

Reversing - Sometimes, depending on how you mount the servo (say upside down) you will want turning left on the transmitter wheel to actually turn right on the servo.

Mixing - Maybe you have a monster truck or crawler that you want to have 4 wheel steering on. You'll have a separate servo on each one. Mixing allows you to blend the two so when you turn, maybe you want it to "crab steer". Maybe you have a gas vehicle with one servo for throttle and a second servo for brakes. You could mix those as well so your trigger is actually moving two servos instead of one.


For brands
I'd stick to Futaba or Airtronics/Sanwa. Spektrum would be my 3rd choice. Futaba and Airtronics use FHSS technology, which is superior to Spektrum's DSM and DSM2 technologies for avoiding interference.

Cheapo Flysky radios also trample over Spektrum signals (it's a Flysky defect, but Spektrum still gets stopmed on). Castle speedos and Savox servos also conflict with Spektrum receivers and cause brownouts. Many Spektrum users are very happy and have never had a problem, but if you plan to upgrade anyway, why set yourself up for potential problems?

So I'd go Futaba or Airtronics. The 3PM-X is a nice mid range radio. The 4PL is a great racing radio. On the Airtronics side, the MT-4 and M11x are nice too.