jr 8103 radio
10-29-2003, 08:03 PM
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jr 8103 radio
ok, so last dumb question. If I get a jr module to put into the trans does that make it pcm or does the receiver getting the signal determine that? And are there fm and pcm frequency modules? or just receivers?
Thanks,
JES
Thanks,
JES
10-29-2003, 10:40 PM
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RE: jr 8103 radio
You select PCM or PPM (FM) in the transmitter. The module will send either signal. The receiver MUST be a PCM receiver. Not dumb questions, just not very straight-forward descriptions in the manuals and in the advertising. Good flying!
10-30-2003, 12:01 AM
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RE: jr 8103 radio
So what function does the module perform. And if I buy a trans without one will it have to be channel specific? if the tx is on ch 42 does the module have to be bought on channel 42 also or does that matter? sorry for all the questions but I need to know this stuff before I jump in blind
10-30-2003, 12:46 AM
#4
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RE: jr 8103 radio
The TX module is the sole source of the actual radio wave output. The TX box just tells the module what song to play....The Module has the crystal in it and other electronics that make the TX a Transmitter.
You can swap modules in the TX's and this can change the frequency you are using say a module on #30 gets swapped with one on #42 the TX box doesn't know what channel its on...only the module by virtue of the crystal inside the module.
As for PCM vs FM the TX box does the digital encoding and sends the signal to the module for output...The data still goes on an FM signal...but instead of the direct commands for the servos PCM is like packaging it up like a little email (encoded).....The RX then takes this email opens it up (decodes) and tells the servos what to do. PCM is Pulse Code Modulation. On an FM system the commands to the servos don't get the little email package....they are directly on the FM signal...its called PPM instead of PCM.
This little email analogy is simplifying it way too much but in lay man's terms it describes what the RX is doing.....Only a PCM RX has the little computer chip in it to decode the packaged email....
If in the TX you select to have it on PCM it turns the little packager on and then for the RX to see anything of useful commands it needs to decode or unpack the signal....When you choose the PPM parameter in the TX it just turns off the packaging system (encoder) and sends the signals within the FM signal....For a PCM RX to get a PPM signal it will not function as the emails are not formated right.
Inside the TX if its PCM selectable it has the stuff to make it PCM. You just need flip the switch in the programming of the radio and have a PCM RX to receive the coded signals.
I hope this helps you out a little
Troy Newman
Team JR
You can swap modules in the TX's and this can change the frequency you are using say a module on #30 gets swapped with one on #42 the TX box doesn't know what channel its on...only the module by virtue of the crystal inside the module.
As for PCM vs FM the TX box does the digital encoding and sends the signal to the module for output...The data still goes on an FM signal...but instead of the direct commands for the servos PCM is like packaging it up like a little email (encoded).....The RX then takes this email opens it up (decodes) and tells the servos what to do. PCM is Pulse Code Modulation. On an FM system the commands to the servos don't get the little email package....they are directly on the FM signal...its called PPM instead of PCM.
This little email analogy is simplifying it way too much but in lay man's terms it describes what the RX is doing.....Only a PCM RX has the little computer chip in it to decode the packaged email....
If in the TX you select to have it on PCM it turns the little packager on and then for the RX to see anything of useful commands it needs to decode or unpack the signal....When you choose the PPM parameter in the TX it just turns off the packaging system (encoder) and sends the signals within the FM signal....For a PCM RX to get a PPM signal it will not function as the emails are not formated right.
Inside the TX if its PCM selectable it has the stuff to make it PCM. You just need flip the switch in the programming of the radio and have a PCM RX to receive the coded signals.
I hope this helps you out a little
Troy Newman
Team JR
