Warning. These receivers will blow up if plugged in the wrong way. Read this post before you use them.
Corona Synthesized Receiver 4Ch 35Mhz

Please note: Only for channels 60 to 80 Specifications:
Weight 0.14oz/4.0g(without shrink wrap)
Sensitivity about 2.0ìV
Selectivity ±8kHz at 65dB down
Number of channels 1-4
Filtering Dual turned RF circuitry
Filtering Dual 4 pole ceramic filter
Filtering DSP filtering in MCU with mild algorithm
Shift polarity Positive or negative (auto-detect)
Case Shrink wrap
Operating Voltage 4.8V~6.0VDC
Operating Current 11mA
Modulate FM/PPM(pulse position modulation)

Due to software problems these receivers CANNOT lock onto frequencies below channel 60.

Giantcod Note The RP4S1 is a receiver which incorporates front end circuitry (aerial input) capable of radio frequency sensitivity in the order of 2u volts. This in simple terms refers to the receivers capability of collecting very weak signals from the transmitter and processing them into useable ‘servo positioning’ data. Considering how tiny these 5 gram receivers are, they provide excellent overall performance. They are made in China by Corona, and the manufactures claim over a mile of ground to air range. Careful and adequate filtering of the received signal is achieved using multiple ceramic filter elements.

The recovered signal from the transmitter is converted to an audible data stream (servo positioning data) which is applied to the clever DSP decoding section. This section separates the relevant servo channels for aileron, rudder, elevator and throttle. The electronic device used in this stage is a micro-processor capable of storing a set of software instructions which are used to further process the servo data and clean out those nasty glitches. The electrical environment within an electric powered model is often very ‘noisy’. Most of this interference being generated by the motor and ESC due to high frequency switching. When a model is seen to suffer from those deadly down elevator glitches etc, replacing the receiver with one from the Corona range will often eradicate such interference completely.

In order to make the most of available space in small models, Corona has adopted an unusual and very compact servo connector arrangement. This still works very well comprising just 4 connectors, battery power is provided via a simple Y lead if all 4 functions are in use. Any servo connector can have the battery supply/servo Y lead or a redundant channel can be used. Don’t bother looking for a crystal socket as this receiver uses synthesised technology to provide the signal normally associated with a plug in crystal to select the operating frequency.

Tuning the Corona RP4S1 is a very simple and quick operation. The receiver has a “tuning” LED and a small button to initiate the channel search process. To tune the receiver to a new frequency, first of all make sure the transmitter is switched on and quite nearby. Connect a servo and battery pack to the receiver, the on-board red LED will blink twice, now with the point of a pen or similar, push the search button once and you will note the LED blinks twice once again. Within a 2 second period after the LED has blinked, press the button once again. You will notice how the LED is now rapidly blinking while the receiver scans the band to find your transmitter. The receiver will usually lock onto the appropriate channel in a matter of seconds, and the indicator LED should now be permanently illuminated. This indicates that tuning has been successfully completed and a suitable channel has been locked.

Take a look at the forum for more details;
Corona 4 Channel receiver manual

Due to software problems these receivers CANNOT lock onto frequencies below channel 60 or above 80.