what does pcm capabilities stand for?

Please see this link:


[link=http://www.aerodesign.de/peter/2000/PCM/PCM_PPM_eng.html]Click me![/link]

For a full technical explanation.

It is another way of encoding 72, 75 & 35 mhz signals.

so if it says it has no pcm capabilities that means?

That you cannot use a PCM receiver with your transmitter.....PPM and PCM are different ways that a transmitter encodes signals to the receiver....PCM selected on a computerized radio will not run a PPM receiver and visa a versa.
Good flyin to ya

What transmitter are you talking about?

PCM at one point was thought to offer many advantages over standard PPM.

Most of those advantages have disappeared as PPM continued to evolve, so the differences are now less pronounced.

Most 72,75 & 35mhz transmitters and receivers support PPM, and you can often use different brands of receivers on PPM systems if the "shift pattern" matches.

As a result, PPM is the most popular encoding mechanism on these frequencies.

PCM is still used on some higher end receivers though, primarily for it's failsafe feature.

That said many cheap synth receivers now also include similiar failsafe features, further eroding the advantages with PCM.

PPM is also required for buddy boxes, and aftermarket 2.4gHz upgrade modules.

So there is no reason to fear getting a PPM transmitter, if you are not going 2.4gHz.

so if i bought a plane scond hand how can i tell if the reciever is pcm or ppm...?

Most will be PPM.

PCM receivers will have the PCM label on them.

Remember though, the shift pattern must match.


Again, which transmitter and which receiver are you talking about?

i have a futaba 7 channel receiver on a 38 channel... and i was looking at purchasing this... http://www3.towerhobbies.com/cgi-bin...I=LXKJD838&P=6 ... and was worried it would not work correctly with it..

Yes it is very likely to work. ( It is OK to have more receiver channels than what your transmitter has ).

However I would STRONGLY advise you to try to get a transmitter with more channels.

You'll later be kicking yourself for not having done so... You will remember this exchange where I told you this.

More channels means that you'll be able to use the transmitter with other planes. Here are some examples...

5 channels may give you enough to handle a plane with retractable landing gear.
6 channels landing gear and flaps
7 channels permits the above with aileron differential
8 channels permits all of the above or quad flaps
9 channels permits all of the above and dual elevator servos
10 channels permits all of the above and/or handling the choke on a gas plane.

etc. etc.

It is better to start out with a quality transmitter, that will handle many different planes, and keep the settings for all of them, than to kick yourself for having limited yourself to 4 channels.

You can also sell a good transmitter later. Cheap ones are not in high demand.

okay great thanks! thats super helpful!! i was wondering also .. my nose cap is screwed on extremely tight what would be the best way or easiest way to get this off?

Look at the label on your receiver. The last letter of the model number will tell you if it will work.
Last letter = "F" will work with the 4EXA
Last letter = "P" will NOT work with the 4EXA

"F" means it is a PPM receiver. People commonly call PPM receivers "FM" and I guess that's where the "F" comes from.
"P" means it is a PCM receiver and it will only work with a Futaba transmitter that is PCM capable.

Look at your Futaba Receiver, If it says 512 or 1024 PCM anywhere on it then no it will not work with the linked Futaba Tx. As has already said the vast majority are PPM(FM) and will work with the linked Futaba Tx.

John

so FP-R127DF means its ppm?

thanks guys!

Yes. That means it WILL work with the 4EXA.

I have two of those receivers. It is an old design, and it has been replaced with smaller lighter models, but they are still very dependable and I plan to kepp them for a long time.

The "D" in the model number also means that it is a "DUAL" conversion RX. Not a really important thing in this case but slightly better than a "SINGLE" conversion unit in the Futaba line. Some other manufacturers make equally good "single" conversion units or use an entirely different tech. Being "D" or "S" does not effect which transmitter will work. The "P" of "F" will effect you.