Oscar-7 Telemetry Format

The Oscar-7 satellite sends CW telemetry on the beacon downlink in the following format.

  100  176  164  178
  280  262  200  254
  375  358  331  354
  453  454  461  459
  541  501  552  529
  600  600  601  651
  Hi Hi

The last value in each telemetry 'frame' should be 649, 650 or 651.

The value indicates the voltage on the A/D reference source for the A/D converter. Without this being nominal, the telemetry data are meaningless and should be discarded.  Note also that each  value also starts with the line number. This is discarded for the purposes of the calculations. Each telemetry value is a two digit number.

These numbers are the raw data values and an equation must be performed on each to reveal a meaningful value.

The equations are listed below.

CH     Parameter Measurement Range                 Calibration Equation

1A Total Solar Array Current 0 to 3000 ma             I = 29.5 N (ma)

1B +X Solar Panel Current 0 to 2000 ma                 I = 1970 - 20N (ma)        

1C -X Solar Panel Current 0 to 2000 ma                 I = 1970 - 20N (ma)

1D +Y Solar Panel Current 0 to 2000 ma                 I = 1970 - 20N (ma)

2A -Y Solar Panel Current 0 to 2000 ma                 I = 1970 - 20N (ma)

2B RF Power Out 70cm/2m 0 to 8 watts                 P = 8(1 - 0.01N)^2 (watts)

2C 24 Hour Clock Time 0 to 1440 min.                   t = 15.16N (min)

2D Battery Charge/Discharge -2000 to 2000 ma     I = 40(N - 50) (ma)

3A Battery Voltage 6.4 to 16.4 V                            V = 0.1N + 6.4 (volts)

3B Half-Battery Voltage 0 to 10 V                            V = 0.10N (volts)

3C Bat. Chg. Reg. #1 0 to 15 V                                 V = 0.15N (volts)

3D Battery Temperature -30 to +50 deg. C                 T = 95.8 - 1.48N (deg.C)

4A Baseplate Temperature -30 to +50 deg. C             T = 95.8 - 1.48N (deg.C)

4B PA Temp. 2m/10m -30 to +50 deg. C                     T = 95.8 - 1.48N (deg.C)

4C +X Facet Temp. -30 to +50 deg. C                         T = 95.8 - 1.48N (deg.C)

4D +Z Facet Temp. -30 to +50 deg. C                         T = 95.8 - 1.48N (deg.C)

5A PA Temp. 70cm/2m -30 to +50 deg. C                     T = 95.8 - 1.48N (deg.C)

5B PA Emit. Current 2m/10m 0 to 1167 ma                 I = 11.67N (ma)

5C Module Temp. 70cm/2m -30 to +50 deg. C             T = 95.8 - 1.48N (deg.C)

5D Instrument Sw. Regulator Input Current 0 to 93 ma    I = 11 + 0.82N (ma)

6A RF Power Out 2m/10m 0 to 10,000 mw                 P = (N^2)/1.56 (mw)

6B RF Power Out 70 cm 0 to 1,000 mw                     P = 0.1(N^2) + 35 (mw)

6C RF Power Out 13 cm 0 to 100 mw                         P = 0.041(N^2) (mw)

6D Midrange Telemetry Calib. 0.500 V                     V = 0.01N(0.50 +/- 0.01) (V)

By applying the appropriate channel equation  to each value, the actual data can be recovered.

I hope to finish a small computer program soon to do the work for me.  I wrote such a program on 2003 but lost it in a computer crash.

DOH!

Al GM1SXX