C141 I'm surprised no one has pointed you at the PlanePlotter website
http://www.coaa.co.uk/planeplotter.htm . You can save third party shared (network) data with the product available from their website called PlanePlotter which enables both SBS-1 and RadarBox local data (plus others) to be shared and logged.
I hope this is not treading on any toes but in my view that this is probably the only fault with Radarbox (or should I say Airnav's policy), which is otherwise a truely exceptional product. That is the fact that they do not allow the network data received to be saved at all and only viewed as a paid option after the first year. Again it is my view that I actually think this would increase their sales (not that they need to at the moment) and the potential of Radarbox to general users. It is after all this same general user base that is supplying the majority of this data to their servers in the first place, but I do acknowledge the fact that AirNav have to manage the storage and sharing of this network data. I also appreciate AirNav have professional products that do enable this network data logging and it is probably purley a commercial decision which have pushed them down this route but AirNav need to recognise that these professional products are priced way out of the reach of the general users who also would like this functionality, so the users are going to look to alternatives like PlanePlotter if AirNav do not or are unwilling to provide this functionality. I therefore plan to use both Radarbox and PlanePlotter to acheive exactly what you are asking for above.
I hope this is an open forum and as such revealing this information is not considered to be forbidden, users of this forum should be pointed at alternative solutions if they exist?
Waiting to be shot down in flames !!!!