Help with Radio terms
04-07-2002, 01:43 AM
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Help with Radio terms
My first plane was a Hangar9 XTRA EASY which came with a 4 channel JR XF421EX radio.
I would like to upgrade to a 6 channel radio but I am confused by some of the terms. I would appreciate some help and advise with the following:
What does PPM/FM and PPM/FM-Invert mean?
What is the difference between the above and a PCM system? Which is better in the long run?
What is the difference between a Digital Servo and the type that came with my radio (517 servos)?
Anything else I should look for in a good radio & servos?
I would like to upgrade to a 6 channel radio but I am confused by some of the terms. I would appreciate some help and advise with the following:
What does PPM/FM and PPM/FM-Invert mean?
What is the difference between the above and a PCM system? Which is better in the long run?
What is the difference between a Digital Servo and the type that came with my radio (517 servos)?
Anything else I should look for in a good radio & servos?
04-07-2002, 02:07 AM
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Help with Radio terms
PPM is a type of modulation from the tx to the rx. PCM is (pulse code modulation) is a coded message that has advantages for larger planes (when you want back up fail safe 
) They are both transmitted on FM frequency. Lots of people think PPM is FM and PCM is... well, PCM... but they are both FM just variations. Don't worry about PCM for a while. Same goes with digital servos. Your 517's are simple analog servos and digitals are digital. Digital has incredible torque around the neutral section but that comes at a price of 2 times as much as a "normal servo."
When you get a 6 channel JR system it is going to be able to do either PPM or PCM, it is selectable in the menu, you don't buy one or the other. The reciver on the other hand is going to be PPM or PCM. For now just but PPM it is a good modulation system. -Steve
) They are both transmitted on FM frequency. Lots of people think PPM is FM and PCM is... well, PCM... but they are both FM just variations. Don't worry about PCM for a while. Same goes with digital servos. Your 517's are simple analog servos and digitals are digital. Digital has incredible torque around the neutral section but that comes at a price of 2 times as much as a "normal servo." When you get a 6 channel JR system it is going to be able to do either PPM or PCM, it is selectable in the menu, you don't buy one or the other. The reciver on the other hand is going to be PPM or PCM. For now just but PPM it is a good modulation system. -Steve
