WingmanEPTX

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hi everyone, beginner here
Q: can i put a futaba rx crystal in my jr reciever ?

i just got a futaba 6ex transmitter channel 36. i have a futaba rx crystal on channel 36. if i put the futaba crystal in my JR reciever (which is currently on channel 36) will it work? will i damage the crystal or the reciever? will it even fit ? i havent tried this yet cuz im scared to screw everything up. also why doesnt my futaba 6ex transmitter (chan 36) control the JR reciever with the JR chan 36 crystal? im guessing its cuz the crystal needs to be the same brand in both rx and tx, but im not sure so hopefully someone can answer this for me!

thanks in advance for any help and answers!
-kevin

RCKen

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The quick and easy answer is - no. You need to get a JR crystal to put in the JR receiver. You can't use the Futaba crystal in it.

Ken

Jetdesign

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http://performancedevices.com/

WingmanEPTX

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ok i have the jr crystal in the jr reciever right now on chan 36, BUT my futaba transmitter(which is on 36) wont control it. can i take the JR tx crystal from my old JR 4 chan Xmitter and put it into the futaba xmitter ? will that work?

RCKen

My Feedback: (9)

Again, no.

JR and Futaba use a different shift in the way the signals are send out (positive shift for JR and negative shift for Futaba). Basically what this means is that even though they are transmitting on the same channel they aren't speaking the same language. That's of course a very simple explanation of what's happening, but you get the idea. Additsionally, it is illegal for the end user to change the crystal in an RC transmitter. For the transmitter crystal to be changed the radio needs to be sent in to a licensed shop that can verify and retune the output of the radio once the new crystal is put in.

What you're going to have to do is either purchase an new JR crystal for your receiver to get it on the same channel as your transmitter, or just buy a new receiver on the same channel.

Ken

WingmanEPTX

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ok lemme ask this...im looking at the manual for my JR RS600 reciever, it says i can change the shift from positive to negative.
it reads: jr has conveniently provided a means to make the rs600 reciever a truly universal piece of equipment by providing you, the end user, with the means to change from the supplied positive (+) shift normal JR operation to the optional negative (-) shift operation by moving a small jumper wire in a block on the PC board. Please proceed as follows. and then blah blah gives intructions on how to do so.
....so if i do this then can i use the futaba crystal in the JR reciver?

haha or am i still way off base and just not getting it? sorry..being a beginner sucks..very humbling!
-kevin

RCKen

My Feedback: (9)

Actually, now you are directly on the matter. Change the shift on the JR reciever (channel 36) to negative and it should then work with the Futaba transmitter.

Ken

WingmanEPTX

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Awsome!!!! thank you soo much Ken! as always i appreciate yours and everyone elses knowledge and for helping us begginers out!
thanks again
-kevin

WingmanEPTX

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oh one more thing.....i dont know yet what these things are: dual conversion, ppm, pcm. but will any of that affect what im trying to do with swapping these crystals ?

JohnBuckner

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Shifting the modulation shift of the tx or the rx if either are selectable to acheve compatabililty is great and of course will work however this has nothing to do with using the wrong crystal type.

There is another factor here and that is the conversion type of the Rx and there is a basic bottom line that a single conversion Rx must use a single conversion type crystal and the same for a dual conversion Rx, it must use a dual conversion type crystal.

You never said what type or the model of the futaba Rx and its conversion type is but the majority are dual conversion therefore the supplied crystal will be a dual conversion type if so.

Now I don,t know JR models numbers very well but I think the 600's are single conversion rx's
Which most use to be and used something called ABC&W filtering. Therefore if this is the case it will require a single conversion crystal and your proposed crystal swap will not work.

There are a lot of pitfalls buy the proper crystal and do not switch the tx crystal either.


John

WingmanEPTX

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ok so if i buy a single conversion futaba crystal and install it in the JR reciever will that work?

RCKen

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Once again - no. You must buy the same brand crystal as the receiver it is going in to. If you are going to use the JR receiver you need to purchase a JR crystal.

Ken

flynte

As mentioned already. You CANNOT use any other manufacturers crystal in a Jr. And when purchasing a Jr crystal for your Jr rx you DO need to make sure if it's a dual conversion or not. A dual conversion crystal won't work in a single conversion rx and vise versa. As you pointed out you could change the shift on your rx to use your Futaba tx.

Happy flying

flynte

WingmanEPTX

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well hot damn!!! put in the JR single conv crystal chan 36, into the JR rx, changed the shift to negative in the rx, and everything works !!!!!!!!!!!!!!! you guys are awsome !!!!! maybe one day in the future...very distant future, ill know what i'm talkin about too! weird though, i had to plug in the servos in a different order than what they are labeled on the rx unit. who cares?!?!? it works now!!!! thank you all for your help!!! is greatly appreciated..now i have to go learn how to program this new futaba x-mitter. ugh! im sure ill be back on help for that! thanks again everyone!
-kevin

scratchonly

AS I understand it the radio uses a particular multiplier of the crystal frequency. All radios work differently,(I think).

JohnBuckner

My Feedback: (1)

There are real reasons that you should never mix brands of rx crystals unless they are an aftermarket type specified for the brand you are putting it into, but folks will argure it to death because they want to save a couple of bucks.

Another factor, Crystals are delicate with a micro thin silicon wafer mounted on two pins inside that crystal and they are damaged and fractured to become intermitant easily in crashs as well as just dropping on a hard floor. For this reason used crystal exchanges or using used crystals is false economy.

You want reliability you will make all Rx purchases with a new proper brand and crystal type or the specified crystals for that Rx. Never purchase a new crystal type Rx without a new appropriate crystal.

The reason you had to use different numbered ports in the JR Rx is not all brand tx's use the same port assignments, It is proprietary. The Rx has nothing to do with it but the Tx has everything to do with it. In otherwords the JR ports 1,2,3,4 and so on are not going be the same ports in the futaba Rx.

John