Interoperability of FoxTrak tracker and Argent Data’s OT3 – Part 1

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:

Rx                Tx
APMI06    APMI06
APMI06    APNU3B
APMI06    FOXTRAK
APNU19    APBL10
APNU19    APERXQ
APNU19    APNU19
APNU19    APNU3B
APNU19    APOT21
APNU19    APOT30
APNU19    APOTC1
APNU19    APOTU0
APNU19    APOTW1
APNU19    APT311
APNU19    APT312
APNU19    APT407
APNU19    APTT4
APNU19    APU25C
APNU19    APU25N
APNU19    APWW10
APNU19    FOXTRAK
APNU19    TINYTRAK
APNU3B    APMI06
APNU3B    APNU19
APNU3B    APNU3B
APNU3B    APOT21
APNU3B    APOTC1
APNU3B    APT314
APNU3B    APTT4
APNU3B    FOXTRAK
APNU3B    TINYTRAK
APNX11    APNX30
APOT21    APBL10
APOT21    APNU19
APOT21    APNU3B
APOT21    APOT21
APOT21    APOT30
APOT21    APOTC1
APOT21    APOTU0
APOT21    APT311
APOT21    APT312
APOT21    APT314
APOT21    APTW01
APOT21    TINYTRAK
APOT30    APOT21
APOT30    APOT30
APOT30    APOTU0
APOT30    TINYTRAK
APTT4    APOTC1
APTT4    APT314
APU25N    APOTC1
APU25N    TINYTRAK
TINYTRAK    APOTC1
TINYTRAK    APT314

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.

References

APRS TO-CALL VERSION NUMBERS