My Dragonfly heli came with an all-in-one black box (pictured below) containing the RX, 2 ESCs, gyro, and mixer. The crystal is 72.870 MHz, which is channel 54.

Since the TX that came with the Dragonfly is pretty dreadful (and configured for Mode 1!), I was hoping I could change the crystal in the Dragonfly RX and so use a different TX. This did not work.

What I did was to simply unplug the original channel 54 crystal and replace it with a spare channel 42 crystal that I had, then try to operate the heli with my channel 42 TX. There was no movement of any of the heli functions. I even tried both single- and dual-conversion channel 42 crystals, though I seriously doubt the Dragonfly RX is dual-conversion.

Do these cheap all-in-one systems have a proproetary modulation scheme that prevents their use with standard RC transmitters? I read this in another forum.

Thanks,
Jeff

The reciever will only work on one band so this may be your problem. You would need to find a tx on 72mhz (channel 52) so that rx and tx are compatable.

mark

i have the 35mhz dragonfly version and my other 35mhz tx will not work with it so its common across the whole range

Hi Mark,

Maybe I wasn't sufficiently clear in my original post.

The receiver in my Dragonfly is on Channel 54 (72.870 MHz).
I wanted to change it to match my transmitter, which is channel 42 (72.630 MHz).

As you can see, both the Dragonfly RX and my TX are on 72 MHz, so the band is not the problem.

I was hoping that I could simply put a new crystal in the Dragonfly RX to change its frequency to channel 42. This did not work.

I do not want to change bands -- I just want to move the Dragonfly RX to a new channel within the 72 MHz band.

- Jeff

Hello JH,

Yes, it's beginning to sound as if the manufacturer has used an incompatible modulation scheme -- probably a cost-saving measure.

I want to use my normal transmitter for the heli so that the control functions will be on the same sticks where I am accustomed to having them. Here in the USA, most of us use Mode 2: aileron and elevator on the right stick, rudder and throttle on the left stick.

Some people have successfully converted the Dragonfly TX from Mode 1 to Mode 2, so that might be my next project.

- Jeff

Your 4-n-1 board looks awfully familiar.

Answer: Yes.

My attempts and consequent conversations with the distributors confirm there is NO known compatibility with any of the name brand radio systems.

IMHO, most of these micro clones are actually very sound and it is the radio and electronics supplied with them that are the weak points.