I have observed an apparent interoperability problem between FoxTrak tracker and Argent Data’s OT3.
Tests have revealed that two FoxTrak’s are not decoded by two OT3s.
There could be many reasons for this, independent of the devices themselves.
To find evidence that OT3 does decode FoxTrak, I have collected just over 17,000 iGate records from APRS-IS and analysed them to try to allocate an equipment type to the first digi in those records, then to find what equipment decoded what other equipment. The APRS TO-CALL version numbers are a potential source of equipment identification, but they are not used universally (eg compressed packets), presence of identifying strings in beacon payload is another source used.
Data was collected from APRS-IS for VK* digis with a PERL script, and equipment type assigned as reasonalby possible, and records written to a SQLITE database. Summary and relational joins were used to produce the final list based on about 8,000 packets.
The absence of an association does not mean they are incompatible, but the presence means that at least some of that type of rx decoded that type of tx.
Here is the list in terms of equipment codes, the first column is the rx equipment and the second is the tx equipment decoding:
Note that some kind of equipment (like the codes for UIDIGI) may be used with one of several types of modem chip. Most of the traffic was to UIDIGIs, next is the Argent Data family.
The thing that is notable, is though there were Foxtrak records for several types, there were none for any Argent and I know that there was exposure of Foxtrack to at least one OT3 during the data collection. Also interesting is that TinyTraks were decoded by OT3, but not FoxTrack yet they are very similar (in fact a trial was conducted on TinyTrakI firmware on a test FoxTrak.
The data analysis is consistent with my observation that I have not been able to get two OT3s to decode two Foxtraks that were decoded just fine my other equipments and other on-air receivers.
More work to be done.