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Old Aug 24, 2008, 10:11 PM
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Can I change the Frequency on my rc helicopter ?

Can I change the Frequency on my 4CH rc helicopter ? Can I ?
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Old Aug 25, 2008, 05:35 AM
A man with too many toys
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I donít know about your 4CH but most have a transmitter module and receiver crystal that you change to get a new frequency. Some of the real cheap radios have to be sent to a service center to change frequencies but it can be done.

If you post all the details if your radio you will get a more exact answer.


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Old Aug 25, 2008, 11:58 AM
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And tell us where you are located. If you are in USA you can't legally change the transmitter crystal.
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Last edited by Daedalus66; Aug 25, 2008 at 05:25 PM.
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Old Aug 25, 2008, 02:38 PM
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Most likely you can change the heli's frequency... within limits of the radio system.

Or you can replace the TX + RX and go to a completely different frequency band... This might entail replacing more because of some helis having "4-in-1" RX/Gyro/ESC/mixing units instead of separate components.

The real quastion is: How hard to you want to work (and how much are you willing to spend) to change the frequeny?
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Old Sep 18, 2008, 08:50 PM
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Mine is a esky co-comanche with 72Mhz
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Old Sep 18, 2008, 10:39 PM
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So you are in the USA? Not legal to change crystal in TX yourself.
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Old Sep 18, 2008, 10:58 PM
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Quote:
Originally Posted by Daedalus66
So you are in the USA? Not legal to change crystal in TX yourself.
Yes, no and maybe...

FCC reg says that you need to have appropriate testing to ensure the TX is properly tuned if you change the crystal.

I'm not sure exactly when they took out the wording that said a qualified technician had to do the crystal change.

However... if you are caught and the TX is found to be out of calibration... there's still up to a $10,000 fine and a year in jail that you could be stuck dealing with.
(I'd rather pay the bench fee for the tuning check...)
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Old Sep 22, 2008, 04:14 AM
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But can I just change 72.150 to 72.450 something?
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Old Sep 22, 2008, 05:02 AM
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Quote:
Originally Posted by WeiJohn002
But can I just change 72.150 to 72.450 something?
If you can find the correct crystal and the change is small yes it will work. It may not be exactly 100% legal but it will work great. Before they changed the law we use to do that all the time. Then you can use it with any of the modern FM receivers.

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Old Sep 22, 2008, 09:21 AM
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Quote:
Originally Posted by RC Man
If you can find the correct crystal and the change is small yes it will work. It may not be exactly 100% legal but it will work great. Before they changed the law we use to do that all the time. Then you can use it with any of the modern FM receivers.


SHOULD work... nope...

Crystals are cut with pretty high precision today.

But JR labels thier crystals with a dot code. The dots indicate if the tests showed the crystal to be top 1/3, center 1/3 or bottom 1/3 of allowable toillerance (showing that JR has every crystal tested for actual frequency)

With JR... if you swap in a crystal with the same dot code, you are going to be VERY CLOSE to properly tuned.

With other brands you don't hav that code and if you happen to swap in a crystal that is max limit off one direction and the original was max limit the opposed direction... you can be significantly OFF frequency.

In the US there are other things operating on the frequencies BETWEEN the ones assigned to RC.
EG: We use 72.070 and 72.090... We USED TO use 72.080... but that got reassigned in the 1980's.

If you cause interference to one of the things operating BETWEEN our frequencies... they can track you down and you can be fined and put in jail.

HOW SMALL THE CHANGE IS (from ch 12 to ch 13 vs from ch 11 to ch 59) HAS NO EFFECT on how accurately the crystals were cut.
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