Company: Corona-rc.com (BACK)
Type: Corona RP8D1 Double Super 35MHz PPM Synthesized Scanning
Microcontroller decoder Atmel ATMEGA88
Receiver system: double converting
1. IF =10.7MHz, 2.IF=455kHz
FM decoder: ceramic resonator
IF filter, 10.7MHz ceramic SAW filter and 455kHz ceramic x 2
RX frequency was accurate within 300Hz
Antenna wire lenght = 99cm
Antenna wire de soldered, and 50 Ohm RF test generator attached.
1kHz sine and 2.5kHz deviation.
The demodulated audio signal was found on a test point.
so it is easy to see with a scope how the receiver perform, when wanted signal is equal to noise,
the RF input signal level is recorded.
Center frequency with best sensitivity -116dBm (0.35uV) so it is far better than the 2uV stated on the parcel, nice.
with -70dBm input level, the frequency width is measured to = 18.0 kHz
with -50dBm input level, the frequency width is measured to = 20.0kHz
that is good, a -50dBm signal is a really strong signal, you need to be under 5 meters away from tx to get that strong signal
Sensitivity to injected noise on the power line
I inject sine wave signals via a 400uH coil and transfer capacitor 100nF,
directly into the power supply connector of the receiver board.
This simulates a bad motor regulator BEC or Servo current pulse, or noise picked up on long power and servo wires
35MHz RF input signal level at -90dBm
Demodulated signal observed as with the sensitivity test.
Noise frequency with best interference = 455KHz,
Input Voltage level when the wanted signal is jammed to 50% signal to noise.
Measured to : not possible for my generator to generate so much signal to even jamm it a little bit. so that is fine for electric planes.
I like to add that the DSP software seems to be working really good.
on a PPM receiver it made me happy to see this perform so smooth and good,
I dont see any servo pulse flips even when TX is turned on/off while RX is running, nice !
10. Nov 2008, Thomas Scherrer