I think I am on its way to track down the weirdness with Type 2 messages.
It seems they only show up if I am also running a receiver with the same call sign and suffix.
I if run a TX sending SM7PNV/7 and a RX with call sign SM7PNV the TX messages don't show up until I change my RX call sign to SM7PNV/7
The Type 2 message don't contain a locator so it is taken from the RX instead of leaving blank.
This a slight problem as well.
So if I send type 1 message as SM7PNV with locator AA00
followed by a type 2 message as SM7PNV/7
the first message will have locator AA00 but the second message will not.
It will have the locator of my receiving station inserted
OK at least know I know how it works, not super useful in my applications.
I was thinking to use it for trackers that could have used the Type 2 message to differentiate between several trackers running at the same time
E.g several balloons or sea buoys operating with the same Call sign but with different suffixes