I have observed recently that two Foxtraks were not decoded by OT3s and OT-USB that should have decoded them.
To futher expore the problem, I pulled about 16,000 records from APRS-IS and looked for evidence that a Foxtrak had been received by any OT device, and I did not find any though I know that at least two should have been decoded by at least four OT devices over some hours. Note that absence of evidence of decoding is not proof of incompatibility, but evidence of decoding would be proof that there is not absolute incompatibility.
I am aware of the frailties and pitfalls of the above method, but it is consistent with my direct tests of Foxtrack with OT3 and OT-USB.
One expert has advised that because Foxtraks are so popular, just dont use OTx for infrastructure.
It is intriguing that I did find evidence of TinyTrak decoded by OTx, but they may not have been early TT. Certainly my tests with OTx on my Foxtrak with DK7IN, aprstracker and TT(1) firware all failed.
I also monitored the traffic on a dedicated channel from a Foxtrak with a T3-135 using PASSALL and it was all jibberish, there was not even short strings of recognisable text. That suggests to me that there is a failure to decode the raw data stream.
Nevertheless, I am interested in solving the problem if it is reasonably feasible.
So, next step is to try and further isolate the problem.
Thoughts include that the incompatibility might be related to clock recovery, data recovery, or packet contents.
I am thinking of capturing the packets from a Foxt
rak (as binary data) from a KISS TNC, then playing it back through a non-OT TNC to see if a OT TNC decodes it. That might indicate whether it is modulation related for packet content related.
I don't want to repeat work already done.
Has someone got relevant information, am I heading down the wrong track (pardon the pun).
Posted by: owenvk-/E1597aS9LT0CCvOHzKKcA@public.gmane.org