hello there
well am still a beginner but i have a question ( could be stupid but never mind : ))
what is the difference between normal radios FM ones and the PCM radios????????????
and for me as a beginner what is the advantage i can get from a PCM, in other words do i have to get it or aget a normal radio.
thanx dudes....have a nice day

sup man,

the advantages of the PCM is it has a fail safe and you dont get as much radio interferance.........i am getting my first one the winter the JR 9X PCM...........you also need a PCM reciver.

that is a can of worms question. I use pcm on gas fm on every thing else,they read the signal different and react different to a bad signal

so dudes, you can say that as a beginner i really dont have to get a really cpmplex radio set, a PCM radio. ???????

as a beginner I would recommend a simple fm 4 ch radio,then as your skills develop you'll have a better idea of the direction you go with your flying,I've seen to many people get in the hobby with to much equiment to start with then wish they had something else on the second or third plane.Keep it simple in the beginning.

Check out www.torreypinesgulls.org/Radios.htm for a pretty good explanation of the different types of encoding signals used in radio control.

I'll second the recommendation to read that Tory Pines article.\

The short answer to your question is "No, you don't need PCM"

In fact, I'd suggest saying away from PCM until you're more familiar with the hobby. A PCM system has a failsafe that has to be set up properly. If you don't set it up right, it can be more harm than good.

Oh, side note, many transmitters can transmit in FM or in PCM modes with just a change of a setting on the transmitter. The receiver, on the other hand, is either one or the other (at least I'm not aware of any switchable receiver). So, there's nothing wrong with getting a PCM-capible transmitter and using it in FM mode with FM recievers until you decide you actually want to go buy a PCM receiver. If you have the money to spend, getting a nicer radio now can be nice, but if you're on a budget, don't bother.

Not directly applicable to the above inita\ial question but: nearly all PCM is FM although you can transmit PCM using AM modulation. Most current transmitters are all FM whether transmitting PCM or PPM or PWM code.

I have been using Futaba radios for about 20 years starting with their Gold series AM radios. I have never had a days trouble with any of them. However, I now have my first PCM radio and it has gone into fail safe a couple of times including once when I was hovering my Raptor. It turned around 180 degrees and started coming straight at me. Took it nearly 30 seconds to return control to me.

I doubt I'll ever use PCM again. I just didn't like that one bit. When using FM I've never even noticed a glitch. If I have gotten any, they were so short that they were imperceptible.

I have been using both, I like PCM better. For a beginner, there probably isn't the justification to spend the extra on it unless you just want it, but for my helicopters and large scale birds, I wouldn't have anything else! I fly PCM almost exclusive and have for years. The only problems I have ever with it going into failsafe were caused by something dumb I did. PCM rocks.

FlyBoy - what do you mean going into failsafe because of something dumb you did???

PCM for me.

I care about my models ... and the people around me.

More reliable radio link (higher signal to noise ratio)
+
Predicatable failure mode (I know my model is not going to head over a crowd if I lose that tenuous radio link due to interference).

It's not about saving the model, it's about saving innocent bystanders.

Choose enhanced safety: Choose PCM, choose fail-safe throttle to idle (minimum).

OK, so I had my heli set up so that it would go to idle and low pitch. It still turned around and came at me. It didn't make it too far before setting down, but it travelled several feet. I'm not saying PCM is bad, but that has been my only experience with fail safe and it was anything but safe.

Fail safe works if you know when and how your radio is going to fail. Anyway, I'm not against it, but I don't see that it's really all that safe because for all you know your plane will be in a situation where having it dive to the ground is the worst thing that it could do. Or having it fly straight and level may be the worst thing it can do. You just don't know what the situation will be when the radio goes into fail safe.

True you don't know what the attitude of the plane will be when you get a hit, But it has been my experience that unless some one turns on a transmitter on the same channel the interference is usually very short lived and you would normaly fly thru it. With pcm and the failsafes set you could possibly recover and save the plane. I have had hits with both fm and pcm. Fm receiver results were plane went full throttle full left aileron and full down elevator, end result one totaled out sig som-thing extra. Pcm receiver engine went to idle and all flight surfaces went to neutral positions which was what I had programed the failsafes to do. The end result was a Dave Patick extra 330L that I regained control of and was able to land safely.
I will stay with Pcm especially as the cost of my planes continues to go up.

Cafeenman, on my giant PT-19, it went into fail safe because I had the switch for the radio and the kill switch to the engine right next to each other. That caused it. Took a while to figure out. On the heli, a bearing was going and that caused it. Equally hard to find. I like having the safety of PCM. I have had a few times when I was in the air someone turn on the same freq. Theirs went nuts, mine never knew. I just think it is safer.

Yeah... I guess I agree that PCM is safer. I'm fortunate in that I belong to a small club and I am the only member on my frequency. I've developed a bad habit of just switching on without having the pin. I need to stop doing that.

Thats what happened at the float fly. A guy that flys by himself turned on when I was up, luckilly, my plane didn't even know it. I watched 2 guys flying in a glider contest one time both on PCM, both on the same ch, standing 50 feet from each other. Then they realized it. Unfortunately, the one that paniced flew over the others head, that was a bad thing. He didn't have the failsafe set and the glider tucked and the wingtip caught a kid. Not a good situation. It is good if set right, but given the wrong flight attitude when it goes into failsafe, or someone not setting it, could lead to disasterous results, just like anything else. It can bite you at times.

I think that is the point.

When you fly your aircraft, you comprehend and accept the risk. The innocent bystander who happened by to watch, or poor soul travelling on a nearby road does not.
PCM (or more specifically fail-safe) gives me some peace of mind in knowing it's unlikely my aircraft will reach them. I've had enough occasion to scare me into converting all my aircraft to pcm over the past few years and I've been thankful I did on more than one occasion.

I have a beginner question about the operation of the failsafe feature I hope someone can answer. If a PCM receiver experiences a situation where the failsafe feature is triggered, does the receiver (1) stay in the failsafe mode until a specified amount of time has past; or (2) stay in the failsafe mode until a specified amount of time has past or until "good" data is received, whichever is less? If the answer is number (2), then it seems that many failsafe modes of operation may be very short, in situations where interference is short duration?

Regards,

Travis

If the receive gets a corrupt data packet (i.e. detects interference), it will respond by simply holding the last servo position.
If the signal interruption persists, then it goes into fail safe. The delay isn't very long. I think just a second, or so.
What happens when it goes into failsafe depends on how you set things up.

The one plane I have with a PCM receiver is setup to idle the engine, and give full rudder/elevator/aileron deflection. As such, it will slow down quickly and spin to the ground in very short order. Hopefully out of harms way. It also lowers the gear - so that it will be abundantly clear what happened.

No disrespect intended... but man would I like to be there the day that happens ... ;-)

gus

Yes, it's drastic

But it's better than it zooming off to who-knows-where.

JimTrainor,

Once a PCM receiver enters the failsafe mode, does it stay there until the time has expired, or will it leave the failsafe mode if it gets a certain amount of "good" data? I am assuming that the receiver is capable of examining data while in safemode and just doesn't ignore all data until a timer has expired.

Travis

It comes back from the brink when it gets a good signal.

It's easy to test, when you're setting it up. Just turn the transmitter off and back on.
It will go into failsafe, then go back to normal once you switch back on.