Davi..when we see a notification on a toy as 27MHz, we will not think much.but there is a heavy science behind it.actually i was making radio cont: sets on 1990s, as i was studying at plus two.i have a good base in electronics from my child hood as my elder brothers were much interested in electronics.my just elder brother Krishna is my Guru in electronics and model making. so i was making my own radio systems from mere wireless FM mikes and a simple FM pocket radio.the 27 MHZ here is the only carrier wave. you can use any carrier wave for you, but within your legal limitation.here in my country toys are allowed in to, 18 MHz to 79 MHz..so..? ample of radio range...in my experience a carrier around 35 MHZ to 40 MHz will be better as they penetrates through many obstacles to me...i can go for from 2 to 22 channels by adding RX 2 ics in line.RX 6 B can hold up to 7 function.i never use any proportional system to me. i consider it as a slavery..with a free motor we can do anything that we think.here with my circuit you can do anything. can turn a motor..can switch a relay..can operate a speed controller with reverse..can make horns..and if you need you can go for a proportional one with 6 additional transiators..all that i cant explain here..so my mail id is MODERATED.please give me a note from you if you need my circuits.i will type all at home and will send you, because i do not have any int connection at home..now i am in a cafe 30 kms from home...happy again...
E-mail address removed, PM Rathi if you want the imformation offered
Brian