• Overview


  • Components



  • Station Layout




  • Link Budget
    • The Ground Station Team is responsible for construction of MEROPE's ground control in Bozeman.
    Team Lead: Keith Mashburn          Past team members: Joe Swanson and Ryland Boren
    Overview

    Working closely with the on-board communications team, the MEROPE Ground Station crew will be responsible for the data exchange with our satellite as it is in orbit. MEROPE has been designed to map solar radiation along its orbit. We hope to use our data to produce an image of the Earth's Van Allen belts. In a nutshell, a geiger tube counts pulses which are then grouped and time-stamped. The information is then stored via internal RAM, until the ground station sends out a "transmit" signal, which begins the downlink. The aforementioned radiation data, along with information regarding internal temperature, solar cell power output, etc. are then translated into binary packets and transmitted at 1200 baud. Here in Bozeman, we receive these signals, (via amateur radio frequencies) translate them back from binary form, and process our information utilizing various softwares.

    The MEROPE ground station will utilize two circularly polarized yagi-style antennas. The antennas are designed to provide gain in the forward direction, while minimizing incoming signals from the sides and rear. In order to use such directional antennas, we are going to utilize automated satellite tracking software and a bi-directional rotator system. This will allow us to track MEROPE as it passes overhead and maintain a reliable downlink with a minimum of RF power.

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    Components:
    Antennas:

    The M2 antennas are perfect for our application. They are very lightweight and yet quite durable. The 2MCP22 is a 2 meter antenna that provides 14 dBi of gain with a 38 degree beam width. The 436CP30 is a 70 cm antenna that provides 16 dBi of gain and a 23 degree beam width.

    2MCP22 436CP30


    For more info on M2 antennas, please visit there website.

    Rotators:

    We are using the Yaesu G-5500 Azimuth/Elevation combination rotator. The rotors will be mounted separately. The azimuth rotor will be bolted to a shelf inside the antenna tower. The elevation rotor will be suspended 8 feet above on an aluminum mast. This will provide better roof top clearance and a wider field of view.

    G-5500

    For more information on Yaesu rotators, please visit there website:

    Tracking Software:

    To track MEROPE as it orbits the Earth, we are using Nova for Windows satellite tracking software. We choose Nova because of its remarkably realistic color maps and its ability to track an unlimited number of satellites, including our own.

    Nova for Windows

    For more information on Nova for Windows, please visit this website:


    Rotor Control:

    To steer our rotor system, we are using the Labjack U12. The U12 is a USB-based multifunction data acquisition and control device. The Northern Lights Software Company, makers of Nova for Windows, designed a " piggy-back" board that allows the U12 to interface directly with Nova. When used together, will have a fully automated satellite tracking station

    Labjack U12Labjack Piggyback

    For more information, please visit this website:

    Transceiver:

    We are using the Icom IC-910H satellite radio. The IC-910H is a 2m/70cm/23cm all mode transceiver. It features two data sockets for simultaneous two band packet communications. This will allow us to send and receive digital packets at the same time.

    ICOM 910-H

    For more information, please visit this website:

    		Station Layout:




    Station Layout


    		Link Budget:
    Item: Source:
    		Uplink:
    		Downlink:
    		Units:








    Frequency: Input
    		437
    		146
    		MHz
    Transmission Path Length: Estimate
    		2264
    		2264
    		km
    Transmitter Power: Input
    		18
    		-3
    		dBW
    Transmitter Line Loss: Estimate
    		-4 dB
    		-1
    		dB
    Transmitter Antenna Gain: Estimate
    		32
    		-10
    		dBi
    Transmission Path Loss: Estimate
    		-0.2
    		-0.2
    		dB
    Space Loss: Estimate
    		-152
    		-143
    		dB
    System Noise Temperature: Estimate
    		35
    		45
    		dB
    Receive Antenna Gain: Estimate
    		-10
    		30
    		dBi
    Receive Antenna Pointing Loss: Estimate
    		-3
    		-3
    		dB
    Data Rate: Input
    		1200
    		1200
    		bps
    Boltzmann's Constant: Constant
    		-228.6
    		-228.6
    		dB
















    Eb/No

    		43.6
    		22.61
    		dB
    EIRP

    		46
    		-14
    		dBW