New-pilot

Hi all, I have a JR7202 radio but can't use it to control my other RTF models. The RTF receivers just don't detect the radio. Is this the way it is or there is a way to correct it?

Thanks.

Missileman

There are a number of things that need to be for the RTF receiver to match your JR radio.
band= I assume your JR radio is 72 Mhz, your RTF receiver also has to be 72Mhz, some are 27Mhz
Channel= If they are the same band they have to be the exact same frequency within that band.("IF" they are the same band you may be able to change the crystal to match your channel if you can find a crystal that is compatable with your receiver)
Shift= JR uses positive shift as does Airtronics, Hitec and Futaba operate on negative shift, Your RTF is anyones guess.
The easiest fix is to replace the receiver with one that is compatable with your radio.

jetmech05

Missleman is 100% correct...by the way it is against the law to change the chrystal in your transmitter....

bruce88123

He's in Canada - our FCC rules do not apply to him but still good advice.

If you could list the EXACT Mfg & Model of radios we could give you better info on this question but what has been said so far is correct.

opjose

The 7202 normally has a pre-installed synth module.

You need to dial the same channel on the TX as on the receiver.

As Missleman stated the shift pattern must match.


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Sidenote:

You CAN effectively LEGALLY change your "crystals" when using most JR radios that have 7 channels and above (with exceptions).

How''s this?

Most JR TX's have tuned modules. The entire RF section is contained within the module itself, so the module is pretuned by JR. Changing the modules does NOT violate FCC regulations while permitting you to switch channels. I've got a handful of them left over from older transmitters which work just fine on the newer ones, including 10+ channel units.

If your JR radio has a fixed freqency module, you may want to consider purchasing the synth module, or a DSM module.

Missileman

Sorry, to clearify my post. I meant he can change the receiver crystal but If he has a synth module that makes it easier, he can dial the transmitter to the receivers channel, again IF the shift is the same.

jetmech05

ahhh I missed where he was from so I'll correct myself....not a wise idea to change chrystals in your transmitter as it can greatly reduce your transmitter's range.....you can send it in to a service center and they can change the chrystal for you then tune the transmitter to the new freq.....
Good Flyin

New-pilot

Thanks all for the info. My JR7202 is synthesize so it can be set to any channel within the 72MHz range. It works fine with JR and Futaba receivers. I have three other RTF models came with their own radios and the crystal can be easily change from the front face. These radios can be interchanged as long as the correct crystal is plugged in. One of them is a 4ch PPM FM radio from E-flite for a Blade CX helicopter. The crystal used is 72.790 MHz, channel 50. But when I set the 7202 to the same channel the receiver just treat it as no transmitter signal found. Same thing happened when I tried the TB-20 RTF plane purchased from Hobby Lobby. It would be nice if one radio can be used to control all the models I have and on top of that, the 7202 offers more options to fine tune the flight characteristics.

Thanks.

bruce88123

The heli radio probably works on opposite shift.

-pkh-

My Feedback: (2)

Yep, the Blade CX is negative shift (like Futaba & Hitec), JR is positive shift (although some of the newer JR radios have selectable shift I believe). I looked at the 7202 manual, and it doesn't look like it has selectable shift.

New-pilot

Two of my helicopters has that 4 in 1 receiver, gyro, speed controller in one case. How can I change the receiver and make the rest to work in the same way?

opjose

You normally will not find a drop in replacement 4 in 1 receiver, though they sometimes can be had if you are lucky. Getting the right shift pattern is tough as often it is not documented for the cheap 4 in 1's...

Your best bet is to get a new receiver and small HH gyro and work from there.

Note that in many cases this will add appreciably to the cost...

-pkh-

My Feedback: (2)

This 4-in-1 unit claims to work with Futaba and JR:

[link=http://tinyurl.com/5k68h9]Blue Arrow 4-in-1[/link]

New-pilot

No, I tried and they don't work with my JR.

krossk

My Feedback: (27)

Don't most 3/4-in-1 units support bypassing the internal RX with an external one? I'm pretty sure the Blade CP does.

New-pilot

Unlike other 4 in 1 units which has two to three boards linked together with sets of pins, the 4 in 1 box of my Blade CX has only one board inside and everything is on that board.