Receiving Rincon 1

Rincon 1 transmits two signals, 1200 baud AFSK/FM data on 436.870 MHz, and a much weaker beacon at 437.345 MHz. Normally only one signal is transmitted at a time.

To receive Rincon 1's AFSK/FM data downlink, you need the following:

1.  The keplerian elements, in order to know where the satellite  location.

2. A radio capable of operating on 436.870 MHz, which changes with Doppler shifting.

3.  A 1200-baud AFSK modem, preferably a very low-end, that does no modulation on its own. Cubesat Groundstation (GS) uses a customer-built hardware modem, and possibly a software modem (using the sound card as an analog-to-digital converter).

To receive Rincon 1's beacon you need to operate your radio in SSB or CW mode near 437.345 MHz. The beacon is a CW carrier with low modulation index audio phase modulation. This modulation type was chosen in order to simplify Doppler tracking and allow demodulation at very low signal levels. The audio modulation input slowly switches through various sensors and modulation frequency represents the sensor's value.

Information about how to decode the beacon and the telemetry will be posted, or you may email rinconsat@gmail.com

The uplink to Rincon 1 is solely for command and control.

Components

Rincon 1 has the following componets included:

• 6 solar cells
• Aluminum frame- built to spin-stabilize through sunlight
• Power board, (used to hold batteries, maintain 5V and 3.3V charges, measure voltages and currents in several spots, and convert the power from the solar cells to usable power.)
• microcontroller board, which is used to gather and transmit telemetry.
• Radio board, which is used for 2 way comunication
• Experiment- Contains a 10 mW beacon board furnished by a student and mentor team working at Rincon Research.

Specifications

These specifications are without respect to the payload.

• Dimensions- 10cmx10cmx10cm
• Mass- max 1 kg (Actual ~900 gram)
• Power Generation- Optimum ~2 W, average on sun side ~1.5 W
• Max power output- 3W when transmitting data
• Min power output- 400mW when in quiet state

Current Status

The rocket containing Rincon 1 was launched, but failed to acheive orbit, and crashed into the earth about 150km from the launch side. It was launched with the UA's SACRED Satellite.

Beacon

Rincon has two telemetry systems, a digital system that samples sensor voltages with a analog-to-digital converter, and an analog system that uses the same sensor voltages to phase modulate the beacon carrier. The beacon will broadcast each sensor value in one 22 second telemetry frame. A 22 second pause will follow each telemetry frame. The beacon call sign is also transmitted in Morse code approximately every eight minutes. Because the beacon is very low power, a regular receiver will probably not receive the signal well enough to successfully demodulate it. However, by sampling pre-detected signals with an analog-to-digital converter, digital signal processing techniques may be used to dramatically improve the signal to noise ratio. A FFT, run 10 times per second, with 10 Hz bin resolution, will allow the frequency between the sidebands and the carrier to be measured accurately. This frequency difference, f, is used to determine the sensor value in the appropriate units. For more details, and to view the formulas to decode the beacon telemetry, see the image below.