Geostreams requires certain properties in a new sensor that are not well documented:

{
"name": name,
"type": "point",
"geometry": geom,
"properties": {
"popupContent": name,
"type":

{ "id": "MAC Field Scanner", "title": "MAC Field Scanner", "sensorType": 4 }

,
"name": name,
"region": "Maricopa"
}
}

Specifically region, name, type.id, type.title, type.sensorType. Not sure if ALL are required but more than it seems from casual inspection.