It is possible to do it, but you need to use the Kinetic Raw data format, not the SBS text format output by dump1090 on port 30003. This normally called the sbs10001 format.
The easiest way, is to set up modesmixer2 and tell it to output that format. You can then point Basestation to it. You can use modesmixer2 to combine your dump1090 and mlat results as well then.
Example modesmixer command:
modesmixer2 --inConnect localhost:30005 --inConnect localhost:30105 --web 8880 --outServer sbs10001:10001
And here it is working in Basestation:
It’s not obvious at all what you need to do, since Basestation just asks for an IP and port, but it’s very old software and pre-dates most of the data formats such as beast format. It was originally intended to connect to the old SBS1 and SBS3 receivers which had a network port on them.
Here’s a thread from @abcd567 with an installation script for modesmixer: