Currently, the only receivers we manufacture that is compatible with the Futaba synthesized equipment is our Fortress series receivers (201FM72 and 202FM72). For an explanation, please read the following:

1) Frequency synthesis is the method whereby a transmitter can be "programmed" to work on any R/C channel; not just one like normal transmitters.

2) With some synthesized systems, the circuit that "locks" on to a frequency does not, by nature, like to change frequencies.

3) When you have FM type transmitters, the very nature of FM modulation means the frequency is constantly shifting back and forth.

4) A PCM system will spend equal amounts of time above and below the center frequency when it is modulating.

5) A PPM system (normal FM like our receivers), spends half as much time above the center frequency as it does below.

6) If the synthesized circuitry for Futaba transmitters is modulated by PCM it will run on frequency. If it then receives PPM data, it might not run on frequency.

7) Our understanding of the technical issues regarding the Futaba synthesized transmitters leads us to believe that Futaba modified the standard PPM modulation scheme defined in the late 60's so that it would spend equal amounts of time above and below center frequency.

8) When the output from these transmitters is fed into a normal PPM receiver, the receiver cannot properly "decode" the altered signal unless either extra componentry is added, or the normal PPM receiver circuitry is fine-tuned to work with the Futaba synthesized output.

If a fixed frequency module is installed into the Futaba transmitters, it outputs normal PPM data and will work with all of our receivers. In our attempts to satisfy the market with smaller and smaller equipment, we have felt it is not beneficial to design our equipment to work with this peculiar transmitter. The FMA Fortress series receivers do operate normally with the Futaba synthesized transmitters, but they are larger and more costly to manufacture.