3.1 Mechanical
3. MSC Interfacing
Mechanical Interface | Thermal Interface
3.1. Mechanical Interface
MiniSatCom is enclosed and potted into a 7075-T6 anodized “component case”. This part has through holes in 3 corners, each 2,26 mm diameter, for a typical 2-56 or M2 fastener to pass through. The enclosure has a 7075-T6 anodized cover installed to protect the PCB from damage, providing a streamlined package for simple integration. The back cover has 3 threaded holes, ANSI 2-56 (American Thread) by default. A back cover with Metric M2 x 0.40 threaded holes is available to replace the American Thread product. A back cover with through holes 2,26 mm in diameter is available to replace the American Thread product.
Total Product Mass: 10 grams
Outside Case Dimensions: 44 x 30 x 5 mm
The radio should be fastened down to a flat surface using the 3 screw locations. The cover should remain installed for typical applications. If a customer requires a custom designed interface or a minimal volume system where the standard cover is interfering or is a prohibiting feature, please contact RadioBro for other options.
American Thread Configuration (Default)
Metric Thread Configuration
Through Hole Configuration
3.1.1. Thermal Interface
MiniSatCom produces heat from its operations, primarily from the high powered amplifier while transmitting. Heat, if not removed, will cause the radio to increase in temperature.
3.1.1.1. Thermal Protection
Two thermal shutdown safety features have been included to protect the radio from internal damage:
Below 70C – Normal operations
Between 70 and 80C – low power transmitting, automatic disable of high powered amplifier
Above 80C – No transmitting, automatic disable of all transmissions
These are default values and can be modified by the user, described in “3.6.2.1.3. Temperature and Voltage Thresholds”.
3.1.1.2. Methods of cooling
The three main modes of heat transfer are conduction, convection and radiation. Convection is not present while operating in a vacuum, so heat transfer must be through conduction and radiation. MiniSatCom is anodized black (emissivity ~0.88) to maximize the radiative heat exchange with the surfaces it is exposed to. Conduction is inherent to the structural contact points.
For many applications, periodic, low duty cycle operations will reduce the need for a complex heat management system. The radio heat will be dissipated through the structural contact points and black body radiation.
For high throughput applications where high duty cycle applications are considered, further consideration should be made to dissipate heat and prevent the protection measures from being triggered:
The radio operates around 50% efficiency (RF power out/electrical power in) when transmitting. Operating the input voltage at the high supply voltage (5V) will minimize the power losses which generate heat.
The heat generating components in the radio are internally potted to one side, labeled “component case”, within the module. Conduction will be most effective while interfacing to the face with the components, minimizing the thermal path from the internal heat sources. The component case is the best side to remove heat from.
Active thermal management systems could be used for continuous operations.
A low thermal resistance path from this surface to the bulk mass will give heat a simple but effective way of conducting the radio heat with the structure.