Raymarine forum

Hi,

Is there any advantage to using Fast Heading (HDM) as an input to my Axiom Pro with a Quantum radar interfaced?

I'm doing some re-wiring and noted that my course computer, Model 400G, has the Fast Heading (HDM) output on one of the NMEA-0183 ports.

The 400G course computer states:
Type 150G and Type 400G course computers provide fast heading
(HDM) output from NMEA 1 at 10 Hz 0.1° resolution. This fast heading data is
suitable for use with the MARPA function on radar equipment.

Is this necessary, or is heading from SeaTalk just fine. I've been running the boat for three years with the Quantum and an Axiom or older eS127 with not noticing a problem.

Thanks, Hube Hopkins

Hello Hube,

There is good news here as you have options. As is the system will work just fine with the heading being converted onto seatalk. If the system performs just fine it is good to go. With the Axiom getting heading through seatalk it is at a 1 hz refresh rate. You can connect the fast heading NMEA0183 out only to the NMEA0183 input on the Axiom pro and it will provide the heading output at 10 hz. When you have a 1hz refresh rate when you go into a large turn you will see a short "lag" on the heading visually as it updates. When you have 10hz in the large turn the heading visually is more of a fluid change. Both setups are adequate and totally safe for Navigation purposes.

Chris,