Yes JM you are right. The xHD and the HD have different protocols.
So, to get the xHD working will take some effort.
There seem to be a lot more message types for the xHD.
How much is known about the older HD radar ?
Dave obviously was able to backward engineer
the protocol for that one.
I see he's been off line for a couple of days. Do you know his strategy ?
If you have a plotter, would it not be possible to feed it recorded data
and then manipulate bit by bit in a packet to determine what that bit/byte
is ? Then connect the plotter to the scanner and record/monitor the
packets going to the scanner. Just some thoughts.