The one radio you said is a PCM 1024 is legal. My Futaba 9CAP is the same type, a PCM 1024 and it's also legal. It is actually the only non 2.4 radio I have that is legal. What makes a radio illegal is if it's a "wideband" transmitter, something that hasn't been sold in 30 years. The difference is a wideband transmits a signal that could vary by up to 40KHz above and below its given frequency. These were made illegal in the early 1990s when the FCC mandated a maximum 20KHz variance, required to increase the number of available frequencies usable for R/C models