About bands and radio control helicopters collectors

There are many crystals and components that determine radio control helicopters functionality. For the low bands, (27 or 41 MHz) should then use a glass half as often, ie with the fundamental at 13.5 MHz or 20.5 MHz to 72MHz But this in 1 / 4 frequencies that is fundamental to 18MHz. In the first case, T1 is the only frequency multiplier, but to 72MHz, you need a second generation later.

Modulation

The frequency modulation, like the multiplication is achieved by the insertion of a variable that affects the glass directly. This capability is achieved on the one hand because Caj and partly due to the variable capacitance diode, which varies according to their ability to signal, is where it regulates the extent to signal. When the modulation voltage applied to diode increases its capacity, decreases and vice versa.

To calibrate the radio control helicopters deviation, see the following example where we have the output frequency is 72100 kHz, and we want a variation of ± 2 kHz then:

      Put Psw to make body contact, and regular Caj 78,098 kHz for the frequency counter.

      Apply a DC voltage of the same amplitude as the signal from the encoder to be used. Then adjust the peak Psw for 72,102 kHz frequency.

      The voltage of the oscillator is stabilized by 10V, thus eliminating frequency shifts occasions by variations in battery voltage.

Voltages

RF voltages generated by the radio control helicopters oscillator (including twice the frequency of the crystal) are amplified by T2. The transistor base is attacked by the signal from the L1 side. The resistor R7 eliminates the tendency to self-oscillation. The efficiency of the stage is adjustable by Pg output is achieved by loading the collector of T2 with L2. At 27 and 41 Mhz, at this point there should be a new frequency multiplication, while in 72Mhz 36MHz signal generated in T1 is again for the 72MHz duplicate. In all cases the mesh filter should pass only the frequency you want and not others, rejecting the fundamental and other unwanted harmonics.

There are two most common types of connection between computers, which are:

      Where the power feed connection passes from teacher to student. In this case the student only has to take off your transmitter and which is fed from the Professor.

      Where the cable connection transmits only one side to another PPM signal and the student must turn on your computer to feed its own battery.

We must not equate the supply radio control helicopters voltage levels if a team uses a different voltage.