K5KNT, yes, this is HM01.
ff  -  HM01 does not send a message the old fashioned way, however unless you write the numbers down and look at them and the cycles they make you might not realize it.
HM01 starts up with 5 figure groups for several minutes.  However, there are only 6 different five figure groups sent, repeated over and over.  This part can sound something like a V02a message, but it is not.  Once the data starts then the same 6 five figure groups are used again, but one at a time, between the data groups.
Example below:
57929   29787   65498   63442   87124   07821
57929   29787   65498   63442   87124   07821
57929   29787   65498   63442   87124   07821
(repeated for several minutes)
57929   data burst  (notice this is the first 5 figure group used above)
29787   data burst  (notice this is the second 5 figure group used above)
65498   data burst  (notice this is the third 5 figure group used above)
63442   data burst  (notice this is the forth 5 figure group used above)
87124   data burst  (notice this is the fifth 5 figure group used above)
07821   data burst  (notice this is the sixth 5 figure group used above)
57929   data burst
29787   data burst
65498   data burst
63442   data burst
87124   data burst
07821   data burst
(repeated 5 figure / data for about 20 minutes)
It then starts over with several minutes of sending 6 different five figure groups over an over before transitioning into the alternating 5 figures / data.
What can confuse some people, make them think there are a couple different formats, is the way HM01 changes frequency.  As I said, the HM01 messages are pretty much always like I have described above.  However, sometimes when the top of the hour comes around and it is time to change frequencies HM01 does not go back to the beginning, but rather just shifts frequency without stopping or changing what it is doing.  This means it can come up on a new freq and be in the middle of the 5 figure / data cycle.  This leads some people to think HM01 starts out with the alternating pattern sometimes.  This habit has caused more than one person to claim finding a “new” mode of HM01.
T!