cloudancer03

My Feedback: (22)

I inherited among everything else a jr pcm rx.I see its discontinued ..was this a good model and would it ok to use with my futaba 9C.I can go PCM or PPM

bruce88123

It definitely won't work in the PCM mode. All of the PCM units are proprietary and do not cross over between brands. I also don't believe the Futaba 9C is capable of changing direction of frequency shift (correct me guys if I'm wrong) and if not it also will NOT work in PPM mode with a JR RX unless you buy a JR RX that is capable of switching shifts. Whew, gets complicated in a hurry.

cloudancer03

My Feedback: (22)

I dont want to argue but if you own a 9C transmitter it is very capable of transmitting in FM or PCM....All I do is go the menu"Parameters" and change to Pulse Code Modulation (PCM) or leave it at PPM(FM).Naturally I know you cant covert a rx back and forth.However and I mean however..as long as my rx is PCM the transmitter using the PCM modulation can communicate with the pcm rx.

Troy Newman

As Bruce tried to say. The PCM system are not the same. Futaba and JR use different PCM systems. PCM is a Pulse Code Modulation. However Futaba and JR use different Codes and different processors to translate the code. The computer coding that is done in the JR systems is not the same coding that is done in a Futaba PCM system. To be specific the JR system is "S" PCM.... Its like talking MAC and PC...

Therefore they are not compatible.

There is also a difference in the Frequency shift as Bruce noted. JR and Futaba equipment use opposing frequency shifts in the North American markets and they do not talk even in PPM (FM) mode. Not that this matters with a R770 as its a PCM RX and is not capable of being used on PPM mode.

JR Sport makes some receivers that can be used with your Futaba TX but this is not a shift selectable RX. In addition to it being SPCM, it will not operate from your Futaba TX.

The R770 is an excellent RX. The only reason is has been discontinued is it was replaced with the R790 Scan Select Synthesized RX. Its basically the same RX but without the crystals for the frequency. The Scan Select technology is really cool as you can have a RX and it can be on any of the channels rather than popping crystals to change channels. This is the only reason the R770 is no longer produced.

I have several and run them currently they are excellent RX's That still doesn't help you operate it with your Futaba 9C.


Troy Newman
Team JR

bruce88123

It's like one person talking in Greek and the other in English. Two fine languages but one can't understand the other. Having PPM with opposite shifts is like leaving out every other word, only worse. You leave out every word. The RX is listening for one language and ignores the other.

cloudancer03

My Feedback: (22)

ok so while I was wrong about compatability I realize now that I can still change modulation with my 9C but it must be within the futaba code modulation .dont get wrong I am not particulary in love with futaba.they can take the acro type parameter and stuff it having spent hours trying to mix a few channels to get crow only to have one of the ailerons lag a bit.I do have Jr servos and feel the stuff is very good.in fact I have the opportunity to own the radio that the new receiver likely operates with.its a older 10sx2 PCM system .what I should do is get it and then use the new rx.you can never have too much equipment.lolotherwise I might as well find the rx a good home.thanks for clearing it up.

cloudancer03

My Feedback: (22)

lol you win bruce I do understand the message.maybe futaba and the others could demand everyone speak the same language eh? sort of like listening to bush and realizing you speak one way and god knows he fractures the language a whole other way.

bruce88123

Ah - Ah - Ah, no politics in the forums

It's too late. Too many millions of units already in use already on both sides. Same thing with the TX charger polarity issue. It is what it is and we just have to deal with it. They MAY have had a chance with 2.4 GHZ but here again every side thinks their system is best. Ford/Chevy/Dodge all over again.

Just enjoy the variety and make your choice. It's hard to make a truely bad choice and something better is always coming soon.

cloudancer03

My Feedback: (22)

yes your right no poltics and normally I frown on that stuff.yeah I agree use what works.I have a lot of futaba though my servos are increasingly hitec or Jr.thank god the servos do what they are told .enjoy the week I just cam back from flying .went with two planes came back with same number minue a landing gear.my depth perception aint what it used to be..

njm

I need help,I'm new at this RC stuff . I did the old school technology back in the early 80's.
I just purchahed aA R C Ready 2 with pontoons. It has an OS FA56 4 Stroke engine in it.
It came with AR770S Receiver Channnel 54 FM 72.870mhz.
I got a Futaba Skysport 4 channel radio with a different channel and mhz.

How do I Make thes compattible? PLease help!!!