RE: Vantec esc
Vantec here. For years we sold the RET series speed controls for all types of radios including AM units. In the early years there was only AM. They worked, some brands better than others. The problems are two fold. The motor brushes of the boat locomotion motor generate considerable Radio Frequency Interference noise. AM radios are MUCH more sensitive to this kind of interference than the FM units. PCM units even screen out the noise mathematically and it is interesting to note the commands are actually sent via a FM type modulation scheme. 2.4GHz is mostly above the noise, but has other issues.
The old AM radio radio can be made to work successfully if all the instructions are followed. RFI supression, capacitors, full antennae, wire routing, etc. As FM radios became more popular we noticed fewer and fewer trouble calls. In Futaba the older AM radios used a different centering 1.3ms than the FM at 1.52 ms and our RET's adjustment pot covered that range. However different connectors were required, this is the second aspect. Today few customers specify the old AM "G" connector instead of the now common "J" or JR style connector. We no longer stock the "G" connectors.
If the AM receiver has "J" connectors or an adapter is fabricated the RET series will work. Just be prepared to (Gulp!) follow the instructions.
Postscript: Theoretically the NARROWBAND FM used for R/C should not be significantly better than AM. It is not the same as comparing AM broadcast radio with FM broadcast. However, because the FM designs are generally better the net improvement is positive.
daylux