QUESTION:
What is the reason for choosing a particular frequency for data
communications between the rover and lander? On Mars, all bands are free.

What is the power, frequency, and antenna gain of the main transmitter? What
are its uplink settings?

ANSWER from Leif Harcke on July 23, 1997:
To save on development costs, we bought off-the-shelf ship-to-shore packet
radio modems from Motorola which operate in the 450 MHz band using 9600 bps
phase-shift keying and the X.25 packet radio protocol.

Spacecraft transmitter - 12.7 watts
Spacecraft high gain antenna - 25 dB gain (transmit)
Frequency - 8.427 GHz
Earth ground station gain (70m antenna) - 74 dB
Earth receiver noise temperature - 22 kelvin (typical)

Earth ground station transmitter - 18 kilowatts
Earth ground station gain (34m antenna) - 67 dB
Frequency - 7.175 GHz
Spacecraft high gain antenna - 21 dB gain (receive)
Spacecraft receiver noise temperature - 287 kelvin (typical)

Yours,
Leif Harcke
Mars Pathfinder Telecommunications Team