What is the difference between 27 MHz, 35 MHz and 2.4 GHz?

The designations 27 MHz, 35 MHz and 2.4 GHz refer to the frequency band on which the transmitter and RC aircraft and RC helicopters operate.

In many countries only allowed for aviation RC (not cars or boats).

Still uses crystals and manual frequency management.

Good range, but largely supplanted by 2.4 GHz systems.

2.4 GHz

• The modern standard for cars, boats, airplanes and drones.
• Works with frequency hopping and digital coupling (bonding) between transmitter and receiver.
• No crystals required; each set automatically selects a free channel.
• More reliable, less prone to interference and often longer range.
• Possibility of additional features such as telemetry and model memory.

Conclusion

27 MHz is an outdated system and prone to interference; 35 MHz was primarily used for aircraft but has largely been replaced; and 2.4 GHz is now the standard: reliable, interference-free, and user-friendly for all RC applications.