27 MHz RC helicopters

27 MHz

— transmitters in this range are simple and inexpensive. At the same time, they have one key drawback — the lack of separation by channels. In fact, this means that it is impossible to use two helicopters with such transmitters side by side — the signals will overlap, making the machines uncontrollable. To avoid this, it is necessary to use replaceable crystal oscillators for retuning to other frequencies, which can be difficult for non-specialists. In addition, the overall functionality of such transmitters is inferior to the capabilities of 2.4 GHz. Therefore, today they are considered obsolete and are rare.